Physical Chemical Changes Review | Before NC Checkin

How confident are you with identifying physical and chemical changes?

• I am not confident at all.

  A physical and chemical what???

• I think I have an idea of what they are.

• I know what the changes are.

• I can teach and explain to someone the differences.

Which action causes a chemical change?

• leaves dropping from a tree

• leaves blowing in the wind

• leaves being burned in a fire

• leaves being crushed into pieces

Answer explanation

Burning is USUALLY a sign of a chemical change.

A student placed an egg in a container of vinegar.

Bubbles formed on the shell of the egg, and after three days, the shell was gone. Which observation made by the student indicated a chemical change took place?

• The bubbles were produced as the shell reacted with the acid.

• The vinegar solution remained clear.

• The temperature of the vinegar remained the same.

• The shape of the egg remained oval.

Over time, iron becomes rust when it combines with water and oxygen. Which type of change must occur for rust to form?

• chemical

• mechanical

• nuclear

• physical

Which describes a chemical change?

• sugar dissolving in tea

• sunshine warming a sidewalk

• scissors cutting paper into pieces

• acid in the stomach digesting food

A type of cold pack has two separate sections inside. One section contains a liquid and the other section contains a powder. When the cold pack is squeezed, the section that holds the liquid breaks. When the liquid combines with the powder, the pack becomes very cold.

Which is the BEST explanation why the temperature of the pack decreases when the liquid and powder combine?

• A mixture forms.

• A solution forms.

• A chemical change occurs.

• Thermal energy is used.

Which property of sugar remains after sugar is dissolved in water?

• color

• taste

• shape

• texture

What happens to colored sugar when it is added to water?

• The sugar reacts and colors the water.

• The sugar becomes white and the water changes color.

• The sugar evaporates and the water changes color.

• The sugar dissolves and colors the water.

How confident are you now with identifying physical and chemical changes?

• I am not confident at all.

  A physical and chemical what???

• I think I have an idea of what they are.

• I know what the changes are.

• I can teach and explain to someone the differences.

The first step in the water cycle is evaporation. What gives water the energy to evaporate?

• sunlight

• wind

• clouds

• waves