Chemistry: Physical vs Chemical Changes Worksheet

Question 1

An ice cube melts into liquid water on a warm table. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the water changes state from solid to liquid, but it is still water.

Question 2

A piece of paper is cut into many small pieces with scissors. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the paper changes size and shape, but the material is still paper.

Question 3

A metal bicycle chain is left outside in the rain and begins to rust. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a chemical change because rust is a new substance that forms when the metal reacts with oxygen and water.

Question 4

A sugar cube dissolves in a cup of hot tea. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the sugar spreads out in the tea, but the sugar molecules are not changed into a new substance.

Question 5

Wood burns in a campfire and produces ash, smoke, heat, and light. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a chemical change because new substances such as ash and gases form, and energy is released as heat and light.

Question 6

A glass cup breaks into several pieces when it falls. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the glass changes shape and size, but the broken pieces are still glass.

Question 7

Vinegar and baking soda are mixed in a cup. Bubbles quickly form and gas escapes. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a chemical change because bubbles of gas form as a new substance is produced during the reaction.

Question 8

A student sharpens a pencil, producing small wood shavings and a sharp point. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the pencil changes shape, but the wood and graphite do not become new substances.

Question 9

Milk is left out for several days and develops a sour smell. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a chemical change because the milk changes into substances with new properties, including a sour odor.

Question 10

A pot of water boils on a stove, and steam rises from the pot. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the water changes from liquid to gas, but it remains water.

Question 11

Classify each change as physical or chemical: tearing aluminum foil, frying an egg, melting butter, and fireworks exploding.

Accepted Answer

Tearing aluminum foil is a physical change. Frying an egg is a chemical change. Melting butter is a physical change. Fireworks exploding is a chemical change.

Question 12

A student observes that two clear liquids are mixed and the container becomes warm. No flame is present. What evidence suggests a chemical change may have occurred?

Accepted Answer

The container becoming warm suggests a chemical change may have occurred because a temperature change can show that energy was released during a reaction.

Question 13

A crayon is melted and poured into a mold shaped like a star. After cooling, the crayon is solid again. Is this a physical change or a chemical change? Explain your answer.

Accepted Answer

This is a physical change because the crayon changes state and shape, but it is still made of the same crayon material.

Question 14

A science class compares two changes. In Change A, salt water is left in a dish until only salt crystals remain. In Change B, a match burns and leaves black ash. Which change is physical and which is chemical? Explain.

Accepted Answer

Change A is a physical change because the water evaporates and the salt remains the same substance. Change B is a chemical change because burning produces new substances such as ash and gases.

Question 15

List three common signs that a chemical change may have happened. Then explain why one sign alone is not always enough proof.

Accepted Answer

Common signs of a chemical change include gas production, color change, temperature change, light production, odor change, and formation of a solid precipitate. One sign alone is not always enough proof because some physical changes can also show similar signs, such as bubbles forming when water boils.

Chemistry: Physical vs Chemical Changes

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