Chemical changes

Which of the following is a sign that a chemical reaction has occurred?

• change in shape
• melting
• formation of a gas
• dissolving

Is melting butter for popcorn a chemical or physical change?

• chemical
• physical

Fizzing, foaming, and burning are all examples of

• Chemical change
• Physical change

Ice melting

• Chemical Change
• Physical Change

Boiling water

• Chemical Change
• Physical Change

An object undergoes a physical change when it changes:

• color, burning, rusting

• shape, form, color

• tarnishing, melting, ashes

An object undergoes a chemical change when it changes:

• shape, form, state of matter

• melting, odor, size

• color, burning, rusting

When tearing a piece of paper, the mass will __________ because of the law of conservation of mass.

• increase

• decrease

• stay the same

Bubbles quickly appear but then they disappear and there is no solid in the final observation.

• physical change

• chemical reaction

The temperature of the solution dropped 18 °C and there was no color change.

• physical change

• chemical reaction