2.3 Physical/Chemical Changes

Which example best describes a chemical change?

• wax melting
• an apple turning brown
• a piece of paper being cut into small pieces

Kim lost her hammer outside. When she found it a few months later, some parts of the metal were covered with flaky, brown rust. Which type of change occurred when rust formed on the hammer?

• chemical
• electrical
• thermal
• physical

Which best explains why burning leaves is a chemical change?

• The leaves emit light during the change. 
• The temperature of the leaves increases.
• The shape of the leaves changes.
• The leaves turn to ashes.

Which is a chemical change?

• frying an egg
• boiling water
• breaking a glass cup
• crushing a piece of bread

Tonya observes a mixture of two clear liquids in a container to see if a chemical change occurs. Which observation demonstrates the mixture is undergoing a chemical change?

• The mixture remains at a constant temperature.
• A gas forms after the liquids are mixed.
• One liquid floats on top of the other.
• The mixture does not change color.

Ramano is burning wood in a bonfire. What change is occurring during the fire?

• The wood is dissolving into liquid.
• The wood is gaining more mass.
• The wood is dissolving into a liquid.
• The wood is releasing a gas as smoke.

Which example best describes a physical change?

• baking a pie
• burning a candle
• making a paper airplane
• lighting a match

Which is an example of the formation of a new substance?

• wax melting

• water boiling

• wood burning

• clothes drying

Which of the following shows a change in which a new substance is NOT created?

• fireworks exploding

• baking soda and vinegar in a volcano

• tearing paper

• lighting a match

Which of the following changes is chemical?

• making fruit salad

• dissolving sugar

• evaporating liquid water

• leaves changing color in the fall