Question

What do these two changes have in common?

- rain forming in a cloud
- breaking a ceramic plate

Select all that apply.
a. both are caused by heating
b. both are chemical changes
c. both conserve mass
d. both are changes of state

Answer 1

Rain forming in a cloud is a physical change, while breaking a ceramic plate is a physical change. Both changes do not involve the formation of new substances.

Step-by-step explanation:

a. Steam is water in the gas phase. When it condenses, changes from gas to liquid, it remains water. Therefore, this is a physical change.

b. When gasoline burns, it changes into different substances. This is a chemical change.

c. When milk becomes sour, several chemical changes have occured; proteins denature, sugars break down, and acid is produced. The milk is now made up of different substances.

d. Sugar dissolves easily into water but it still remains sugar. If the water is evaporated, the sugar will recrystalize as a solid again. Dissolving is a physical change, the substance does not change.

e. Melting solid gold into liquid gold is a physical change much like melting solid water (an ice cube) into liquid water is a physical change.