Unit 2 Test Review

Which of the following observations suggest a chemical change is taking place?

• a change in size and shape

• a change in mass or volume

• a change in state

• the formation of a precipitate

A student watches ice creams melt into a puddle of cream. Has a chemical reaction taken place?

• yes, a gas has been given off

• no, cream does not react chemically

• yes, the color has changed

• no, no new substance has formed

Which of the following is not a physical property of matter

• state of matter

• shape

• flammability

• hardness

Which statement is correct?

• Neither physical nor chemical changes

  are reversible.

• Physical changes are not reversible.

• All chemical changes are reversible

• Most chemical changes are not

  reversible

Which of these is a chemical property, not a physical property?

• mass

• color

• ability to burn

• ability to dissolve

A physical property of a substance

• is observed by changing the identity of the substance

• is anything that physically exists or occurs

• can be observed without changing the identity of the substance

• must be observed by touching the substance

To identify a substance by its density

• mass and volume

• mass and weight

• shape and volume

• weight and shape

Density, melting point, and boiling point are all examples of

• physical properties

• chemical properties

• physical changes

• chemical changes

Sammy’s tools rusted and turned a reddish brown. He said it was a physical change. Is he correct?

• Yes, it is a physical change because color

  is a physical property.

• No, it is a chemical change because

  rusting produces a new substance.

• Yes, it is a physical change because it is

  still his tools.

• No, it is a chemical change because the

  rust can be removed.

What evidence shows that ice has a physical change when left out in a room?

• It reacts with oxygen in the air.

• It is hard and white

• It changes to water.

• It is cold to the touch