Free Printable Signs of Chemical Reactions

1.

Evidence of a chemical reactions is anything that shows -

a)

a new substance has formed

b)

a solid dissolved in a liquid

c)

interaction between 2 gases

d)

a change in the state of matter

2.

One of the signs of a chemical reaction taking place is:

a)

Bubbles are produced

b)

Reactants are not combining

c)

Products are not forming

d)

Color is not changing

3.

Which is NOT an indication of a chemical change?

a)

temperature change

b)

formation of a precipitate

c)

shape change

d)

production of light

4.

You know you a chemical reaction has occurred if

a)

there is a precipitate.

b)

there is a color change.

c)

there is a temperature change.

d)

All of these answers are evidence.

5.

A clear liquid from a flask is poured into another clear liquid in a beaker. Which of the following results of this procedure would indicate a new substance was formed?

a)

The level of the substance in the beaker is higher after the other liquid is added.

b)

A yellow solid forms and then settles to the bottom of the beaker.

c)

Small white crystals are left behind in the flask that held the first liquid.

d)

The mass of the combined liquids is greater than either original liquid.

6.

Which of the following is an example that includes evidence of a chemical reaction?

a)

A sample of zinc is placed in water and it settles to the bottom

b)

A solid block of ice is heated and it completely melts into a liquid.

c)

Sugar that is burned gives off an odor and turns brown and then black.

d)

A tomato is placed into a blender and chopped up into smaller pieces.

7.

A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because bubbles -

a)

could show that a gas is forming.

b)

always rise to the top of a liquid.

c)

are almost always perfectly spherical.

d)

usually burst after a few minutes.

8.

A chemical reaction that transfers energy from the reactants to the surroundings is referred to as

a)

exothermic

b)

endothermic

c)

paleothetic

d)

exergonic

9.

What type of reaction has the reactant broken down into other substances?

a)

synthesis

b)

decomposition

c)

combustion

d)

single replacement

10.

What type of reaction is energy transferred from the surroundings to the reactants

a)

exothermic

b)

polyatomic

c)

endothermic

d)

polygenic

11.

What type of reaction is the this $CH_4\ +\ 2O_2\ \rightarrow\ CO_2\ +\ 2H_2O$

a)

synthesis

b)

decomposition

c)

combustion

d)

double displacement

12.

What type of reaction is this $2NH_3\ \rightarrow\ N_2\ +\ 3H_2$

a)

synthesis

b)

decomposition

c)

single displacement

d)

double displacement

13.

What type of reaction is this $2NaCl\ +\ H_2SO_4\ \rightarrow\ Na_2SO_{4\ }+\ 2HCl$

a)

synthesis

b)

decomposition

c)

combustion

d)

double displacement

14.

What type of reaction is this $Fe\ +\ S\ \rightarrow\ FeS$

a)

synthesis

b)

decomposition

c)

single displacement

d)

free radical

15.

What type of reaction is this $2Li\ +\ 2H_2O\ \rightarrow\ 2LiOH\ +\ H_2$

a)

redox

b)

decomposition

c)

single displacement

d)

combustion

Signs of Chemical Reactions

Total questions: 15

Worksheet time: 18mins

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