5th Grade Science Quiz: Evidence Of New Substance Formed
20 questions · exam conditions
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Evidence Of New Substance FormedQuestion 1 of 20

Based on the observations, Student A says, "A new substance formed because the mixture changed from clear to green." The student mixed 50 mL of blue sports drink with 50 mL of yellow sports drink. The temperature stayed at 20°C, no bubbles formed, and the smell stayed the same. Is Student A's reasoning correct?

Yes, because any color change is always evidence of a chemical change.
No, because the green color can be explained by mixing two colors, with no other reaction signs.
Yes, because the temperature stayed the same, which proves a reaction happened.
No, because chemical changes only happen when a solid is mixed with a liquid.
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5th Grade Science Quiz

5th Grade Science Quiz: Evidence Of New Substance Formed

Practice Evidence Of New Substance Formed in 5th Grade Science with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Evidence Of New Substance Formed, giving you a quick way to practice the rules, question types, and explanations that matter most for 5th Grade Science.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Based on the observations, Student A says, "A new substance formed because the mixture changed from clear to green." The student mixed 50 mL of blue sports drink with 50 mL of yellow sports drink. The temperature stayed at 20°C, no bubbles formed, and the smell stayed the same. Is Student A's reasoning correct?

  1. Yes, because any color change is always evidence of a chemical change.
  2. No, because the green color can be explained by mixing two colors, with no other reaction signs. (correct answer)
  3. Yes, because the temperature stayed the same, which proves a reaction happened.
  4. No, because chemical changes only happen when a solid is mixed with a liquid.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically evaluating whether evidence supports new substance formation and distinguishing predictable color mixing from chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, blue + yellow drinks making green with no other changes - predictable physical color mixing, not chemical change. Choice B is correct because it correctly recognizes that green color can be explained by simple color mixing (blue + yellow = green) without any other reaction signs, showing the student understands to look for multiple indicators and that predictable color mixing is physical. Choice A represents a common error where students think any color change is always evidence of chemical change, which typically happens because students may focus on most obvious change (color) without checking for additional evidence or considering whether the color change is predictable from mixing. To help students: Show that color change alone is weak evidence - demonstrate both physical color mixing (food coloring) and chemical color change (with bubbles/temperature), emphasizing the need for multiple indicators. Watch for: Students who conclude chemical change from color alone without checking temperature, gas, or smell, or who don't distinguish between predictable color mixing (physical) and unexpected color change with other indicators (chemical).

Question 2

A student says, "A new substance formed because the mixture got warmer." In the investigation, students mixed 100 mL of cold water (10°C) with 100 mL of hot water (50°C). The final temperature was 30°C, and there were no bubbles, no new smell, and no solid formed. Based on the evidence, is the student's reasoning correct?​

  1. Yes, the reasoning is correct because any temperature change means a chemical change happened. The final temperature proves a new substance formed.
  2. Yes, the reasoning is correct because hot and cold water always react together. Mixing different temperatures makes a new substance.
  3. No, the reasoning is not correct because the temperature changed due to mixing hot and cold water. The evidence does not show a reaction making heat or gas. (correct answer)
  4. No, the reasoning is not correct because water cannot be measured in degrees Celsius. Without correct units, you cannot decide.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically connecting observations to conclusions through reasoning. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Temperature change only counts as chemical evidence if from reaction itself, not from adding hot/cold substance. For this question, hot and cold water mixed showing predictable temperature averaging - physical change. Choice C is correct because it correctly identifies that temperature change from mixing hot and cold water is not evidence of chemical reaction. This shows the student understands must distinguish reaction-produced changes from external changes. Choice A represents a common error where students think temperature change from adding hot water is evidence of chemical reaction (it's not - must come from reaction itself). This typically happens because elementary students may not yet understand that temperature change must come from reaction itself, not external source. To help students: Use side-by-side comparison of chemical (baking soda + vinegar) vs physical (salt + water) so students see difference. Watch for: Students who think temperature change from adding hot water is evidence of chemical change.

Question 3

Two groups mixed different substances in cups at room temperature (22°C). Group 1 mixed lemon juice and baking soda. Group 2 mixed sugar and water. Group 1 saw lots of bubbles and the temperature dropped to 19°C. Group 2 saw the sugar disappear, no bubbles, and the temperature stayed 22°C. Based on the data shows, which group most likely formed a new substance?

  1. Group 2 because the sugar disappeared, which means it turned into something new. Disappearing is the strongest evidence of a chemical change.
  2. Group 1 because bubbles formed and the temperature changed without adding hot or cold. These indicators support a chemical change. (correct answer)
  3. Both groups because mixing any two substances always makes a new substance. Every mixture is a chemical change.
  4. Neither group because you cannot know without looking under a microscope. Evidence must always be microscopic to be valid.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically evaluating whether evidence supports new substance formation. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Temperature change only counts as chemical evidence if from reaction itself, not from adding hot/cold substance. For this question, Group 1 (lemon juice + baking soda) showed bubbles and temperature drop - chemical indicators, while Group 2 (sugar + water) showed only dissolving - physical change. Choice B is correct because it correctly identifies that Group 1's multiple indicators (bubbles + temperature change) support chemical change while Group 2's dissolving is physical. This shows the student understands to compare evidence between groups. Choice A represents a common error where students think dissolving is chemical change because substance 'disappears' (it's physical - still there in tiny pieces). This typically happens because dissolving seems so dramatic that 5th graders assume it's chemical, but substance is still present and recoverable. To help students: Use side-by-side comparison of chemical (acid + base) vs physical (sugar + water) so students see difference. Practice comparing data tables to identify which group has stronger evidence. Watch for: Students who think dissolving is chemical change. Students who don't compare evidence between groups systematically.

Question 4

After mixing blue food coloring into water, the student observed: the color spread through the water, there were no bubbles, no new smell, and the temperature stayed at 23°C. Based on the observations, which conclusion is best?

  1. A new substance formed because the color changed from clear to blue. Any color change is always a chemical change.
  2. No new substance formed because the food coloring just mixed and spread out. With no bubbles, smell, or temperature change, it is a physical change. (correct answer)
  3. A new substance formed because the water is now different and cannot be called water anymore. Any mixture is a chemical change.
  4. No new substance formed because the water got colder from the reaction. A temperature change proves it was only physical.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing predictable color mixing (physical) from unexpected color change (chemical). To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, food coloring spreading in water with no temperature change, no bubbles, and no new smell indicates physical change - the dye simply dispersed. Choice B is correct because it correctly identifies this as physical change, recognizing that food coloring just mixed and spread out without any chemical indicators present. This shows the student understands that predictable color mixing (adding colored substance to clear water) is different from unexpected color change (two clear liquids becoming colored). Choice A represents a common error where students think any color change is chemical change, not distinguishing between adding color (physical) and creating new color (chemical). This typically happens because students focus on the most obvious change (color) without checking for other chemical indicators. To help students: Demonstrate the difference between adding color (food coloring, paint mixing) which is physical, versus creating new color (two clear liquids becoming yellow) which suggests chemical change, emphasizing need for multiple indicators. Watch for: Students who think all color changes are chemical, students who don't check for additional evidence beyond color, or students who think any visible change means new substance formed.

Question 5

After mixing 200 mL of room-temperature water (20°C) with 1 tablespoon of salt, students observed: the salt "disappeared" after stirring, there were no bubbles, and the temperature stayed 20°C. The mixture tasted salty. Based on the observations, is this a chemical change (new substance formed) or a physical change (no new substance formed)?

  1. Chemical change, because the salt disappeared so it must have turned into something new. Disappearing is proof of a reaction.
  2. Chemical change, because tasting salty means a new substance formed. New tastes always mean chemical change.
  3. Physical change, because the salt dissolved but is still salt mixed in the water. There were no bubbles or temperature change to show a reaction. (correct answer)
  4. Physical change, because any time you stir a mixture it becomes a new substance. Stirring causes chemical changes.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Dissolving looks dramatic but is physical change because substance still present. For this question, salt dissolved in water showing no temperature change, no bubbles, still tastes salty - physical change. Choice C is correct because it correctly recognizes dissolving is physical change because salt still present and recoverable. This shows the student understands must distinguish reaction-produced changes from external changes. Choice A represents a common error where students think dissolving is chemical change because substance 'disappears' (it's physical - still there in tiny pieces). This typically happens because dissolving seems so dramatic that 5th graders assume it's chemical, but substance is still present and recoverable. To help students: Demonstrate that dissolved substances are still there by evaporating salt water to recover salt, showing dissolving is reversible (physical). Watch for: Students who think any dramatic change is chemical (including dissolving).

Question 6

After mixing the substances, two students disagreed. They mixed 100 mL of water with 5 drops of blue food coloring. The color spread through the water in about 20 seconds, there were no bubbles, the temperature stayed at 21°C, and the mixture still smelled like water. Student A says, "A new substance formed because the water changed color." Student B says, "No new substance formed because it was just mixing." Based on the evidence, who is correct and why?

  1. Student A is correct because any color change proves a chemical change. The blue color could not happen without a reaction.
  2. Student B is correct because the evidence shows only predictable mixing with no bubbles, no temperature change, and no new smell. These observations do not strongly support a new substance forming. (correct answer)
  3. Student A is correct because the color spread quickly. Fast changes are always chemical changes.
  4. Both students are correct because the result could be chemical or physical. You can never tell from observations.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. For this question, food coloring spread in water with no temperature change or bubbles - physical change. Choice B is correct because it correctly distinguishes predictable color mixing (physical) from unexpected color change (chemical). This shows the student understands must distinguish reaction-produced changes from external changes. Choice A represents a common error where students conclude chemical change from only one weak observation (just color) without checking for stronger evidence. This typically happens because students may focus on most obvious change (color) and not check for more important evidence (temperature from reaction, gas produced). To help students: Show that color change alone is weak evidence (could be mixing colors), but color + temperature + gas together is strong evidence. Watch for: Students who don't check temperature or gas production, only notice color; Students who think all visible changes are chemical changes.

Question 7

The evidence from this investigation is incomplete. Lila mixed 1 teaspoon of baking soda into 50 mL of lemon juice. She wrote, "It fizzed a lot," but she did not measure temperature, did not note any smell change, and did not record how long the fizzing lasted. What additional observation would BEST help determine if a new substance formed?

  1. Measure the temperature before and after mixing without adding hot or cold water. A temperature change from the reaction would be strong evidence of chemical change. (correct answer)
  2. Write down the color of the cup used for mixing. The cup color helps decide if a new substance formed.
  3. Count how many times the spoon was stirred. More stirring always causes chemical changes.
  4. Measure the height of the student who did the experiment. Taller students usually get stronger reactions.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically identifying which observations constitute evidence of chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Temperature change only counts as chemical evidence if from reaction itself, not from adding hot/cold substance. For this question, baking soda and lemon juice mixed showing fizzing - but incomplete without temperature. Choice A is correct because it correctly identifies temperature change without external heat as key chemical change evidence. This shows the student understands certain observations are reliable indicators of chemical change. Choice C represents a common error where students make conclusion without using evidence, just guessing. This typically happens because students may think their prediction is their conclusion rather than using actual evidence. To help students: Practice Claim-Evidence-Reasoning structure: state conclusion, cite observations, explain how observations support conclusion. Watch for: Students who confuse their prediction with their evidence-based conclusion; Students who can identify observations but can't explain WHY they indicate chemical vs. physical change.

Question 8

Based on the evidence from this investigation, a student mixed 10 g of salt into 100 mL of room-temperature water (20°C) and stirred for 30 seconds. The water stayed clear, no bubbles formed, and the temperature stayed at 20°C. The salt seemed to disappear, and the water tasted salty. The student evaporated the water overnight and got salt crystals back. Is this a chemical change or a physical change, and what evidence supports it?

  1. It is a chemical change because the salt disappeared, which means it turned into a new substance.
  2. It is a chemical change because the water tasted salty, which shows a new substance formed.
  3. It is a physical change because the salt dissolved and could be recovered by evaporating the water. (correct answer)
  4. It is a chemical change because stirring causes reactions that cannot be reversed.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, salt dissolved in water showing no temperature change, no bubbles, still tastes salty - physical change, and critically, the salt was recovered by evaporation proving it's still the same substance. Choice C is correct because it correctly recognizes dissolving is physical change because salt still present and recoverable, showing the student understands that dissolving is physical not chemical. Choice A represents a common error where students think dissolving is chemical change because substance 'disappears' (it's physical - still there in tiny pieces), which typically happens because elementary students may not yet understand that dissolved substances are still present, just broken into tiny pieces too small to see. To help students: Demonstrate that dissolved substances are still there by evaporating salt water to recover salt, showing dissolving is reversible (physical), and teach explicitly that dissolving breaks substances into tiny pieces but doesn't change what they are. Watch for: Students who think any dramatic change is chemical (including dissolving) or who confuse disappearing with chemical change when the substance is just spread out in tiny pieces.

Question 9

Students mixed 200 mL of room-temperature water with 2 teaspoons of salt and stirred for 1 minute. The salt "disappeared," the water stayed clear, the temperature stayed at 21°C, and there were no bubbles or new smell. The next day, they left the salt water in a shallow dish and the water evaporated, leaving white salt crystals. Based on the evidence from this investigation, what is the best conclusion?

  1. A new substance formed because the salt disappeared. If you cannot see it, it must have turned into something new.
  2. No new substance formed because the salt dissolved and could be recovered by evaporating the water. The observations match a physical change. (correct answer)
  3. A new substance formed because crystals formed after a day. Crystals always mean a chemical change happened.
  4. Not enough evidence was collected because students did not measure the mass. Without mass, you can never decide if a new substance formed.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Dissolving looks dramatic but is physical change because substance still present. For this question, salt dissolved in water showing no temperature change, no bubbles, still tastes salty - physical change. Choice B is correct because it correctly recognizes dissolving is physical change because salt still present and recoverable. This shows the student understands dissolving is physical not chemical. Choice A represents a common error where students think dissolving is chemical change because substance 'disappears' (it's physical - still there in tiny pieces). This typically happens because dissolving seems so dramatic that 5th graders assume it's chemical, but substance is still present and recoverable. To help students: Demonstrate that dissolved substances are still there by evaporating salt water to recover salt, showing dissolving is reversible (physical). Practice identifying which changes are reversible (physical) vs hard to reverse (chemical). Watch for: Students who think any dramatic change is chemical (including dissolving). Students who don't understand dissolving is physical because substance still present and recoverable.

Question 10

Two students mixed sand and water in a jar. They observed: the sand stayed visible, most sand settled to the bottom after 2 minutes, there were no bubbles, and the temperature stayed the same. Based on the observations, what is the best conclusion?

  1. A new substance formed because the sand moved to the bottom. Movement in a jar is evidence of a chemical change.
  2. No new substance formed because the sand and water stayed as separate parts. The mixture can be separated by pouring or filtering. (correct answer)
  3. A new substance formed because the water looked less clear. Any change in how clear water looks is a chemical change.
  4. No new substance formed because sand is not allowed to react with water. Some substances cannot be mixed at all.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. For this question, sand and water mixed showing no temperature change, no bubbles, sand still visible and separable - physical change. Choice B is correct because it correctly identifies that substances remaining separate and easily separable indicates physical change. This shows the student understands dissolving is physical not chemical. Choice C represents a common error where students think all visible changes are chemical changes. This typically happens because students may not realize that physical changes can look dramatic (dissolving, color mixing) but are still physical because original substances are still present. To help students: Emphasize that dissolving is physical (common misconception). Watch for: Students who don't understand dissolving is physical because substance still present and recoverable.

Question 11

Students mixed 100 mL of water with 1 spoonful of sand and stirred. The sand stayed visible and settled to the bottom after 2 minutes. The temperature stayed at 23°C, and there were no bubbles or new smell. Based on the observations, is this a chemical change (new substance) or a physical change (no new substance)?

  1. Chemical change because the sand moved around in the water. Movement shows the substances reacted to form something new.
  2. Physical change because the sand and water stayed the same and could be separated. Settling is evidence of a mixture, not a new substance. (correct answer)
  3. Chemical change because the water looked dirty. Any change in how clean it looks means a new substance formed.
  4. Physical change because the temperature stayed the same, and temperature is the only evidence that matters. If temperature does not change, a reaction cannot happen.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically identifying which observations constitute evidence of chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. For this question, sand mixed with water showing no temperature change, no bubbles, sand still visible and settles - physical change. Choice B is correct because it correctly identifies that sand and water staying separate and being easily separated shows physical change. This shows the student understands that substances keeping their properties indicates physical change. Choice C represents a common error where students think any visible change (water looking dirty) means chemical change. This typically happens because students may think all visible changes are chemical changes without understanding that physical mixtures can look different but substances remain unchanged. To help students: Emphasize that in physical changes, the original substances keep their properties and can be separated. Practice separating mixtures (filtering sand from water) to show substances are unchanged. Watch for: Students who think any change in appearance means chemical change. Students who don't recognize that easy separation indicates physical change.

Question 12

Based on the observations, which situation is MOST likely a physical change (no new substance formed)?

  1. 1 tablespoon of sugar mixed into warm water: sugar disappeared; no bubbles; temperature stayed 25°C.
  2. Vinegar mixed with baking soda: many bubbles; foam rose; temperature dropped 4°C.
  3. Yeast mixed with sugar and warm water: after 10 minutes, bubbles appeared and the smell changed.

Which choice best matches the evidence?

  1. Situation 2, because foam is a sign of dissolving. Dissolving means no new substance formed.
  2. Situation 1, because dissolving can be reversed by evaporating the water and there were no other reaction signs. No bubbles and no temperature change support a physical change. (correct answer)
  3. Situation 3, because bubbles that start later always mean air got stirred in. That is a physical change.
  4. All three are chemical changes because the mixtures looked different after mixing. Any change in appearance proves a new substance formed.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Dissolving looks dramatic but is physical change because substance still present. For this question, sugar dissolved in water showing no temperature change, no bubbles - physical change. Choice B is correct because it correctly recognizes dissolving is physical change because substance still present and recoverable. This shows the student understands dissolving is physical not chemical. Choice D represents a common error where students think all visible changes are chemical changes. This typically happens because physical changes can look dramatic (dissolving, color mixing) but are still physical because original substances are still present. To help students: Demonstrate that dissolved substances are still there by evaporating salt water to recover salt, showing dissolving is reversible (physical). Watch for: Students who think any dramatic change is chemical (including dissolving); Students who don't understand dissolving is physical because substance still present and recoverable.

Question 13

The data shows results from three mixes:

  • Mix 1: Sand + water: sand settled to the bottom after 2 minutes; no bubbles; temperature stayed 20°C.
  • Mix 2: Sugar + water: sugar dissolved; no bubbles; temperature stayed 20°C; liquid tasted sweet.
  • Mix 3: Vinegar + baking soda: lots of bubbles and foam started in 3 seconds; temperature dropped from 20°C to 16°C.

Based on the evidence, which mix most clearly formed a new substance (chemical change)?

  1. Mix 1, because the sand moved to the bottom and that shows something new was made. Settling means the sand reacted with the water.
  2. Mix 2, because the sugar disappeared and the water tasted different. Disappearing is the best sign of a chemical change.
  3. Mix 3, because bubbles formed quickly and the temperature changed without adding hot or cold water. Two strong indicators together show a new substance formed. (correct answer)
  4. All three mixes formed new substances because they all looked different after mixing. Any visible change means a chemical change.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically identifying which observations constitute evidence of chemical change and using multiple pieces of evidence together. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Multiple indicators together provide stronger evidence than single observation. For this question, baking soda and vinegar mixed showing bubbles, temperature drop, and fizzing - all chemical indicators. Choice C is correct because it correctly identifies that multiple indicators (temperature drop + gas produced + fizzing) together provide strong evidence of new substance. This shows the student understands multiple observations provide stronger evidence than one and certain observations are reliable indicators of chemical change. Choice D represents a common error where students think all visible changes are chemical changes. This typically happens because physical changes can look dramatic (dissolving, color mixing) but are still physical because original substances are still present. To help students: Use side-by-side comparison of chemical (baking soda + vinegar) vs physical (salt + water) so students see difference; Emphasize that good science uses multiple pieces of evidence, not just one. Watch for: Students who think any dramatic change is chemical (including dissolving); Students who make conclusions based on one observation without checking for additional evidence.

Question 14

The data shows what happened when two substances were mixed in a sealed plastic bag.

  • Before: 2 tablespoons baking soda in one corner, 30 mL vinegar in another corner.
  • After the bag was shaken: strong fizzing sound; many bubbles; bag inflated in 10 seconds; temperature dropped from 22°C to 18°C.

Based on the evidence from this investigation, which observation is the strongest evidence that a new substance (a gas) formed?

  1. The bag inflated in 10 seconds after mixing. The inflation shows gas was produced, which is strong evidence of a chemical change. (correct answer)
  2. The bag was made of plastic. Plastic bags always cause chemical changes when you shake them.
  3. The baking soda started in a corner before mixing. Starting in a corner shows a new substance formed later.
  4. The temperature dropped from 22°C to 18°C, so it must be from cold air in the room. That means no new substance formed.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically identifying which observations constitute evidence of chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Multiple indicators together provide stronger evidence than single observation. For this question, baking soda and vinegar mixed showing bubbles, fizzing, temperature drop, and gas inflating bag - all chemical indicators. Choice A is correct because it correctly identifies gas production as strong evidence of chemical change. This shows the student understands certain observations are reliable indicators of chemical change. Choice D represents a common error where students think temperature change from adding hot water is evidence of chemical reaction (it's not - must come from reaction itself). This typically happens because elementary students may not yet understand that temperature change must come from reaction itself, not external source. To help students: Teach the key chemical change indicators explicitly (temperature without external heat, gas produced, unexpected color, precipitate, new smell, hard to reverse) and practice identifying them. Watch for: Students who think temperature change from adding hot water is evidence of chemical change; Students who make conclusions based on one observation without checking for additional evidence.

Question 15

After mixing the substances, a student wrote four observations. Which observation is the best evidence that a new substance formed (chemical change)?

  1. The liquid changed from clear to a new milky white color.
  2. The temperature stayed the same.
  3. The mixture could be poured into a new cup.
  4. The spoon got wet.
  1. Observation 2, because staying the same temperature proves a reaction happened slowly. Slow reactions do not change temperature.
  2. Observation 3, because pouring shows the substances combined into something new. If you can pour it, it is a chemical change.
  3. Observation 1, because a new milky color can mean a new solid formed in the liquid. An unexpected color change is evidence of a chemical change. (correct answer)
  4. Observation 4, because a wet spoon means the liquid reacted with metal. Any wetness shows a new substance formed.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically identifying which observations constitute evidence of chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, the key is recognizing that a new milky color can indicate precipitate formation (solid particles forming in liquid), which is a strong chemical change indicator. Choice C is correct because it correctly identifies that a new milky color can mean a new solid formed in the liquid (precipitate), and recognizes that unexpected color change is evidence of chemical change. This shows the student understands that certain observations are reliable indicators of chemical change, particularly when clear liquids become milky/cloudy. Choice A represents a common error where students misinterpret temperature staying the same as evidence of a slow reaction, when actually no temperature change simply means no heat was released or absorbed. This typically happens because students may not yet understand that not all chemical reactions produce temperature changes, and that stable temperature is neutral evidence. To help students: Teach the key chemical change indicators explicitly, emphasizing that milky/cloudy appearance often indicates precipitate (new solid) formation, while routine observations like pouring ability or wetness are not chemical indicators. Watch for: Students who think temperature must always change in chemical reactions, students who focus on irrelevant observations (wetness, pourability), or students who don't recognize that cloudy/milky appearance is fundamentally different from simple color mixing.

Question 16

After mixing the substances, Jordan stirred 200 mL of room-temperature water (22°C) with 2 teaspoons of salt. The salt "disappeared," there were no bubbles, the temperature stayed at 22°C, and the water tasted salty. The next day, the teacher left the cup in a warm sunny window and the water evaporated, leaving white salt crystals. Based on this evidence, is this a chemical change or a physical change?

  1. It is a chemical change because the salt disappeared in the water. When something disappears, it must have turned into a new substance.
  2. It is a chemical change because the water evaporated later. Evaporation always means a new substance formed.
  3. It is a physical change because the salt dissolved but stayed the same substance. Getting the salt back after evaporation shows no new substance formed. (correct answer)
  4. It is a chemical change because the water tasted salty. A new taste proves a new substance formed.
Explanation: This question tests a 5th grader's ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically distinguishing chemical change evidence from physical change evidence. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Dissolving looks dramatic but is physical change because substance still present. For this question, salt dissolved in water showing no temperature change, no bubbles, still tastes salty - physical change. Choice C is correct because it correctly recognizes dissolving is physical change because salt still present and recoverable. This shows the student understands dissolving is physical not chemical and must distinguish reaction-produced changes from external changes. Choice A represents a common error where students think dissolving is chemical change because substance 'disappears' (it's physical - still there in tiny pieces). This typically happens because dissolving seems so dramatic that 5th graders assume it's chemical, but substance is still present and recoverable. To help students: Demonstrate that dissolved substances are still there by evaporating salt water to recover salt, showing dissolving is reversible (physical); Practice Claim-Evidence-Reasoning structure: state conclusion, cite observations, explain how observations support conclusion. Watch for: Students who don't understand dissolving is physical because substance still present and recoverable; Students who confuse their prediction with their evidence-based conclusion.

Question 17

After mixing 30 mL of vinegar and 1 teaspoon of baking soda in a clear cup, students recorded these observations: bubbles and foam started within 2 seconds, the cup felt cooler, and the temperature dropped from 22°C to 18°C without adding ice. Based on the observations, did a new substance form (chemical change) or not (physical change)?

  1. No new substance formed because the foam is just air trapped from stirring. The temperature drop happened because the cup was held in students' hands.
  2. A new substance formed because gas bubbles appeared and the temperature changed without adding hot or cold. Two strong indicators together support a chemical change. (correct answer)
  3. No new substance formed because the baking soda dissolved in the vinegar. Dissolving always means the original substances stayed the same.
  4. A new substance formed because the mixture looked cloudy for a moment. Cloudiness alone proves a chemical change happened.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically using multiple pieces of evidence together. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. Physical changes show dissolving (substance breaks up but still there - can recover it), predictable color mixing, separation, or state changes. Multiple indicators together provide stronger evidence than single observation. For this question, baking soda and vinegar mixed showing bubbles, temperature drop, and fizzing - all chemical indicators. Choice B is correct because it correctly identifies that multiple indicators (temperature drop + gas produced + fizzing) together provide strong evidence of new substance. This shows the student understands multiple observations provide stronger evidence than one. Choice A represents a common error where students think temperature change from external source (hands) explains the observation. This typically happens because elementary students may not yet understand that temperature change must come from reaction itself, not external source. To help students: Use side-by-side comparison of chemical (baking soda + vinegar) vs physical (salt + water) so students see difference. Emphasize that good science uses multiple pieces of evidence, not just one. Watch for: Students who don't understand temperature change must be from the reaction itself, not from holding the cup or adding hot/cold substances.

Question 18

A class did two mixing tests.

Test 1: Sugar + water → sugar seemed to disappear, no bubbles, temperature stayed at 20°C, and the liquid tasted sweet.
Test 2: Vinegar + baking soda → lots of bubbles and foam, and temperature dropped from 21°C to 17°C.

Based on the evidence, which test shows a chemical change (new substance formed)?

  1. Test 1, because the sugar disappeared and that proves it turned into a new substance. Disappearing is stronger evidence than bubbles.
  2. Test 1, because tasting sweet means a new substance formed. New tastes always mean a chemical change occurred.
  3. Test 2, because bubbles formed and the temperature changed without an outside source. Using two indicators makes the evidence stronger. (correct answer)
  4. Both tests, because all mixing creates a new substance. Anytime you combine materials, it is a chemical change.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically comparing evidence from multiple tests to identify chemical versus physical changes. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, Test 1 shows sugar dissolving (physical) with no chemical indicators, while Test 2 shows vinegar and baking soda with bubbles and temperature drop - clear chemical indicators. Choice C is correct because it correctly identifies Test 2 as showing chemical change, recognizing that bubbles formed and temperature changed without an outside source, and notes that using two indicators makes evidence stronger. This shows the student can compare different mixtures and identify which has chemical change evidence. Choice A represents a common error where students think dissolving sugar is chemical change because it 'disappears,' even claiming it's stronger evidence than bubbles. This typically happens because dissolving seems so dramatic that students don't recognize it as physical change where sugar remains present unchanged. To help students: Use side-by-side demonstrations comparing dissolving (sugar in water - physical) with reacting (baking soda + vinegar - chemical), highlighting the presence or absence of key indicators in each. Watch for: Students who think dissolving is chemical change, students who value 'disappearing' over actual chemical indicators like gas production, or students who think all mixing creates new substances.

Question 19

Two students disagree about a mixture. Student A says, "A new substance formed because the powder disappeared in water." Student B says, "No new substance formed because there were no bubbles, no temperature change, and we could get the powder back by evaporating the water." Based on the evidence, who is correct and why?

  1. Student A is correct because disappearing always means a chemical change. If you cannot see it, it must have turned into a new substance.
  2. Student B is correct because dissolving can be a physical change, and getting the powder back shows it was reversible. No bubbles or temperature change also suggests no new substance formed. (correct answer)
  3. Student A is correct because evaporation is a chemical change that creates a new powder. That means the original powder was destroyed.
  4. Neither student is correct because you must know the chemical formula to decide. Observations cannot be used as evidence in science.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically evaluating whether evidence supports new substance formation and understanding reversibility. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, the key evidence is that the powder could be recovered by evaporation, proving it was still present unchanged (physical change). Choice B is correct because it correctly recognizes dissolving can be physical change, uses the reversibility evidence (getting powder back) effectively, and notes absence of chemical indicators. This shows the student understands that recovering original substance through evaporation proves no chemical change occurred. Choice A represents a common error where students think disappearing always means chemical change, not understanding that dissolved substances are still present in tiny pieces. This typically happens because dissolving seems so dramatic that 5th graders assume the substance is destroyed, not realizing it's just spread throughout the water. To help students: Demonstrate evaporation recovery with salt water or sugar water, showing that getting the original substance back proves it was physical change - if it were chemical, you'd get a different substance back. Watch for: Students who think dissolving destroys substances, students who don't understand that reversibility is key evidence for physical change, or students who ignore the powerful evidence of substance recovery.

Question 20

After mixing 30 mL of vinegar with 1 teaspoon of baking soda in a clear cup, students made these observations: bubbles formed right away, the mixture foamed up, and the temperature dropped from 22°C to 18°C without adding ice or cold water. Based on the observations, did a new substance form (chemical change) or not (physical change)?

  1. No new substance formed because the bubbles were only air that got trapped while stirring. A physical change can make foam when you mix fast.
  2. Yes, a new substance formed because gas bubbles appeared and the temperature changed without an outside heat source. These are strong signs of a chemical change. (correct answer)
  3. No new substance formed because vinegar and baking soda can be separated easily by filtering. Filtering always brings back the original substances.
  4. Yes, a new substance formed because the mixture looked cloudy for a moment. Any cloudiness always means a chemical change happened.
Explanation: This question tests 5th graders' ability to use evidence to determine whether mixing substances resulted in a new substance forming (NGSS 5-PS1-4), specifically using multiple pieces of evidence together to identify chemical change. To determine if a new substance formed (chemical change), students must analyze observations for key indicators: temperature change without external heat source, gas produced (bubbles, fizzing), unexpected color change, solid forming from liquids (precipitate), new smell, or inability to easily reverse. For this question, baking soda and vinegar mixed showing bubbles, temperature drop (from 22°C to 18°C without adding cold), and fizzing - all chemical indicators working together. Choice B is correct because it correctly identifies that multiple indicators (temperature drop + gas produced + fizzing) together provide strong evidence of new substance formation, and specifically notes the temperature changed without an outside heat source. This shows the student understands that multiple observations provide stronger evidence than one alone and that temperature change must come from the reaction itself. Choice A represents a common error where students dismiss bubbles as just trapped air from stirring, not recognizing that immediate bubble formation with fizzing indicates gas production from a chemical reaction. This typically happens because 5th graders may not distinguish between mechanical bubbles (from stirring) and chemical gas production (immediate upon mixing). To help students: Use side-by-side comparison of mechanical stirring bubbles (temporary, from agitation) versus chemical reaction bubbles (immediate, continuous, with fizzing sound), and emphasize that multiple indicators together (bubbles + temperature change + fizzing) provide conclusive evidence. Watch for: Students who think all bubbles are just trapped air, students who don't recognize that temperature dropping without adding cold substances is strong chemical evidence, or students who focus on one observation while ignoring the pattern of multiple indicators.