Question

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1. which one of the following examples does not involve a chemical change? (1pts)

□ a fish that is left for some time in an unrefrigerated place decomposes.
□ apple juice, which is left in an open bottle, ferments.
□ a loaf of bread rises and its volume expands when it is baked in an oven.
□ when a lake starts to freeze in winter, ice is formed on the surface.
□ when sugar is fermented under certain conditions, alcohol is produced.

1. which is an example of a physical change? (1pts)

Explanation:

1. A chemical change creates new substances, while a physical change only alters form/state. Fish decomposition, apple juice fermentation, bread baking, and sugar fermentation all produce new chemicals. Lake freezing only changes water from liquid to solid ice, no new substance.
2. A physical change is a reversible change in state/form without new substances. Freezing water into ice is a phase change (liquid to solid) with no new chemical formed, matching this definition. The other options involve new substance production, which is chemical change.

Answer:

1. $\boldsymbol{\square}$ When a lake starts to freeze in winter, ice is formed on the surface.
2. $\boldsymbol{\square}$ When a lake starts to freeze in winter, ice is formed on the surface.