All flashcards
Flashcard 1: What is the best indicator that only an observable change happened, not a weight change?
Answer: The scale reading stays the same. Unchanged scale readings prove mass conservation occurred.
Flashcard 2: Identify the observable change when ice melts into liquid water.
Answer: Change of state from solid to liquid. Melting is a physical state change you can see.
Flashcard 3: Which option is an observable change during rusting: color change, or scale reading change?
Answer: Color change. Rust appears orange/brown, changing the metal's appearance.
Flashcard 4: Which option is most likely to cause total weight to decrease in an open container: dissolving salt or evaporation?
Answer: Evaporation. Water vapor escapes to air, reducing system mass.
Flashcard 5: Choose the correct conclusion: A sealed bag is weighed before and after shaking; the scale matches. What changed?
Answer: An observable change may occur; total weight did not change. Sealed bags prevent mass loss; only arrangement changes.
Flashcard 6: Which option is an observable change that does not require a scale: bubbles forming or mass staying constant?
Answer: Bubbles forming. Bubbles are visible; constant mass requires measurement.
Flashcard 7: Identify the best claim: A powder is mixed with water; the color changes, but the sealed cup weighs the same.
Answer: Observable change occurred; total weight stayed the same. Sealed container preserves mass despite visible changes.
Flashcard 8: Choose the correct statement about dissolving sugar in water in a closed container.
Answer: It is an observable change; total weight stays the same. Sugar disappears visually but mass remains constant when sealed.
Flashcard 9: Which option best indicates a total weight change: new texture, or a different number on the scale?
Answer: A different number on the scale. Texture is sensory; scale numbers quantify weight changes.
Flashcard 10: What is the best definition of an observable change in a material or object?
Answer: A change you can detect with senses (look, smell, feel, hear). Observable changes are detected directly without measuring tools.
Flashcard 11: What is the meaning of an open system in a weight investigation?
Answer: Matter can enter or leave the system. Open systems allow mass exchange with surroundings.
Flashcard 12: Which option best describes evaporation: observable change, total weight change, or both?
Answer: Both (observable change and total weight change in an open system). Water vapor escapes (weight loss) and state changes (observable).
Flashcard 13: What is the key difference between an observable change and a weight change?
Answer: Observable changes affect appearance; weight change affects the measured total weight. Observable = sensory detection; weight = numerical measurement.
Flashcard 14: Which option is a total weight change: tearing paper or losing gas from a container?
Answer: Losing gas from a container. Gas escaping reduces system mass; tearing keeps all matter present.
Flashcard 15: Identify whether this is observable or weight: a solid changes into a liquid.
Answer: Observable change. State changes are visible but don't affect total mass.
Flashcard 16: Identify whether this is observable or weight: the balance reading decreases after opening a lid.
Answer: Change in total weight. Opening allows matter to escape, reducing measured weight.
Flashcard 17: Which option shows no total weight change in a closed container: fizzing or mass leaving the container?
Answer: Fizzing in a closed container. Closed containers prevent gas escape, maintaining total weight.
Flashcard 18: What does it mean if total weight changes in an investigation of a reaction?
Answer: Matter entered or left the measured system. Weight changes only when matter crosses the system boundary.
Flashcard 19: Identify whether this is observable or weight: a liquid changes from clear to cloudy.
Answer: Observable change. Clarity changes are visual observations.
Flashcard 20: Identify the tool used to measure total weight in grams during an experiment.
Answer: A balance (scale). Balances measure mass/weight in standard units.
Flashcard 21: What is the rule for total weight in a closed system after a change?
Answer: Total weight stays the same. Conservation of mass: matter cannot be created or destroyed.
Flashcard 22: Identify whether this is observable or weight: the total weight increases after adding a metal washer.
Answer: Change in total weight. Adding matter increases the system's total mass.
Flashcard 23: Identify whether this is observable or weight: the balance reading is unchanged after stirring a mixture in a sealed jar.
Answer: No change in total weight. Unchanged readings confirm mass conservation in closed systems.
Flashcard 24: What is an observable change in a material?
Answer: A change you can detect with senses, such as color, shape, or state. Observable changes are detected through sight, touch, smell, taste, or hearing.
Flashcard 25: A bag is sealed. It bubbles and inflates, but the scale reading is unchanged. What changed?
Answer: Observable change occurred; total weight did not change. Sealed bags trap gas, maintaining constant mass.
Flashcard 26: What does a change in total weight mean in an investigation?
Answer: The measured weight of all materials together changes. Total weight is the sum of all material masses in the system.
Flashcard 27: Which tool is used to measure total weight in a science lab?
Answer: A balance or scale. Scales measure mass by comparing gravitational force.
Flashcard 28: Which option is an observable change: color change or total weight change?
Answer: Color change. Color is a visual property detected by sight.
Flashcard 29: Which option is a total weight change: new odor or a different scale reading?
Answer: A different scale reading. Scale readings directly measure mass changes.
Flashcard 30: Identify the observable change: ice melts into water, and the mass stays the same.
Answer: Change of state (solid to liquid). Melting changes physical form but not mass.