Physical and Chemical Changes

Answer each question by clicking the correct blue button. Only the first answer selected is graded.

1.  Which of the following is a chemical change?
A. dissolving sodium hydroxide into water.
B. sublimation of dry ice into carbon dioxide gas.
C. combustion of hydrogen gas with oxygen gas to make water.
D. fractional distillation of crude oil .

2.  Which of the following is a physical change?
A. a sodium pellet oxidizing in air.
B. an acid neutralizing a base to form salt and water.
C. erosion of a riverbed by water.
D. digestive fluids breaking down food.

3.  Which of the following factor combinations is evidence of the occurrence of a chemical change?

a. smell

b. color change

c. production of gas

d. production of heat

e. change in size

f. change in shape

g. change in phase

h. formation of a precipitate

i. production of light


A. a, e, f, g, h.
B. b, c, d, h, i.
C. a, b, c, d, g.
D. b. e, f, g, i .

4.  When sedimentary rock is formed by the evaporation of water, what type of change(s) is(are) involved?
A. a physical change
B. a chemical change.
C. both physical and chemical changes.
D. neither physical nor chemical changes.

5.  Fill in the blank with the best answer. When an egg rots, milk sours or an apple slice turns brown, a(n) ________ change occurs.
A. physical.
B. phase.
C. chemical.
D. appearance.

6.  When a change in phase occurs, which of the following can occur?
A. heat is taken in and the temperature increases.
B. heat is taken in and the temperature does not change.
C. heat is released and the temperature decreases.
D. heat is released and the temperature increases.

7.  Which of the changes below is a chemical change that occurs during the making of a car?
A. painting the car body.
B. making plastics from oil products.
C. making steel from metals.
D. rolling the steel into sheets.

8.  Chemical weathering happens when minerals present in rock are:
A. crushed.
B. heated.
C. fragmented.
D. exposed to acid.


Grade exam.