All flashcards
Flashcard 1: Which property should you record before and after mixing to check for temperature change?
Answer: Temperature. Heat changes indicate energy released or absorbed in reactions.
Flashcard 2: Identify the best conclusion: After mixing, the liquid turns cloudy and a solid settles out.
Answer: A precipitate formed; evidence suggests a chemical change. Cloudiness and solid formation indicate a precipitation reaction.
Flashcard 3: Which property should you compare before and after mixing to test for an energy change?
Answer: Temperature. Heat absorbed or released indicates chemical energy changes.
Flashcard 4: What does it mean if the mixture can be separated by evaporation after mixing?
Answer: A dissolved solid was present; it is a solution (mixture). Evaporation removes solvent, leaving dissolved substance behind.
Flashcard 5: Identify the term for a mixture that looks the same throughout after mixing.
Answer: Homogeneous mixture (solution). All parts have the same composition and appearance.
Flashcard 6: Identify the term for a mixture with visibly different parts after mixing.
Answer: Heterogeneous mixture. Different regions have different compositions or appearances.
Flashcard 7: What property change after mixing most strongly suggests a solid formed from liquids?
Answer: A precipitate forms (new solid appears). Solid particles forming from mixed liquids shows a chemical reaction.
Flashcard 8: What property change after mixing most strongly suggests a gas was produced?
Answer: Bubbling or fizzing appears. Gas formation indicates a chemical reaction occurred.
Flashcard 9: Which observation is the best evidence that mixing caused a chemical change?
Answer: Formation of a new substance. New substances have different properties than the originals.
Flashcard 10: Identify the best conclusion: After mixing, the substances can be separated by filtering.
Answer: No new substance is confirmed; it is likely a physical mixture. Separation by filtering shows substances didn't chemically react.
Flashcard 11: What observation after mixing is evidence of an energy change without heating the container?
Answer: The mixture temperature changes. Temperature change without external heat indicates a chemical reaction.
Flashcard 12: What is the definition of a chemical change when substances are mixed?
Answer: A change that forms one or more new substances. The original substances react to create different substances.
Flashcard 13: What is the definition of a physical change when substances are mixed?
Answer: A change in form or properties with no new substance formed. The original substances remain but may look different.
Flashcard 14: Which option best describes mixing sand and water: homogeneous or heterogeneous mixture?
Answer: Heterogeneous mixture. Sand particles remain visible and don't dissolve in water.
Flashcard 15: What does it mean if the mixture can be separated by filtering after mixing?
Answer: A solid is present; it is likely a mixture, not one pure substance. Filtering separates components that didn't chemically combine.
Flashcard 16: Which option best describes dissolving sugar in water: physical change or chemical change?
Answer: Physical change. Sugar molecules spread between water molecules without reacting.
Flashcard 17: What observation after mixing is evidence that light energy was released?
Answer: The mixture gives off light. Light emission indicates energy release from a chemical reaction.
Flashcard 18: What observation after mixing is evidence of a smell change that may indicate a new substance?
Answer: A new odor appears. Different smell suggests new chemical compounds formed.
Flashcard 19: Which property should you compare before and after mixing to test if a new gas formed?
Answer: Presence of bubbles or gas release. Bubbles show gas molecules forming from the reaction.
Flashcard 20: What observation after mixing is evidence of color change that may indicate a new substance?
Answer: A new color appears. Color change often indicates new chemical compounds formed.
Flashcard 21: Identify the best conclusion: After mixing, bubbles form and temperature drops noticeably.
Answer: Evidence suggests a chemical change occurred. Bubbles and temperature drop are signs of a chemical reaction.
Flashcard 22: Identify the evidence of change when vinegar and baking soda are mixed and many bubbles form.
Answer: Gas produced (evidence of chemical change). Bubbles show CO₂ gas forms from the acid-base reaction.
Flashcard 23: Identify the type of change when sand is mixed with water and can settle out over time.
Answer: Physical change (mixture; no new substance). Sand doesn't dissolve; particles just spread out and can be filtered.
Flashcard 24: Identify the type of change when salt is mixed into water and the salt is no longer visible.
Answer: Physical change (dissolving; no new substance). Salt separates into ions but remains salt; can be recovered by evaporation.
Flashcard 25: What observation after mixing is strong evidence of a chemical change: a solid forms, faster stirring, or smaller pieces?
Answer: A solid forms (a precipitate). Precipitates form when dissolved substances react to create insoluble products.
Flashcard 26: What observation after mixing is strong evidence of a chemical change: light produced, clearer label, or louder timer?
Answer: Light produced. Light emission indicates energy release from chemical bond changes.
Flashcard 27: What is the correct term for the substance that does the dissolving in a solution?
Answer: Solvent. The substance doing the dissolving, like water dissolving sugar.
Flashcard 28: What is the correct term for the substance that dissolves in a solution?
Answer: Solute. The substance being dissolved, like sugar in water.
Flashcard 29: What is the name for a mixture in which one substance dissolves evenly in another?
Answer: Solution. A homogeneous mixture where particles are evenly distributed.
Flashcard 30: What is the definition of a physical change when materials are mixed?
Answer: A change in form or state with no new substance formed. Matter changes appearance but keeps its chemical identity.