Section 3.2
Changes in Matter
Practice Test
1.
How can the law of conservation of mass apply to a burning log, if all that remains of it is ash?
a.
The ash has the same mass as the log, although a large percentage of it blows away.
b.
The law of conservation of mass applies to changes of state but not to chemical reactions.
c.
The law of conservation of mass applies to substitution and displacement reactions, but not to combustion reactions.
d.
The masses of the gases and water vapor released into the air by the combustion reaction plus the mass of ash equal the mass of the log before burning.
Hint
2.
The statement, "Mass can neither be created nor destroyed" is the ____________.
a.
law of conservation of mass
b.
law of conservation of energy
c.
law of multiple proportions
d.
law of gravity
Hint
3.
In the following chemical reaction, how do you classify hydrogen and oxygen?
2H
2
+ O
2
→ 2H
2
O
a.
products
b.
reactants
c.
physical changes
d.
chemical properties
Hint
4.
How would you read the following chemical reaction?
2Cu + O
2
→ 2CuO
a.
copper yields oxygen and copper(II) oxide
b.
copper(II) oxide yields oxygen and copper
c.
copper and oxygen yield copper(II) oxide
d.
oxygen yields copper and copper(II) oxide
Hint
5.
How can you tell when the following reaction is balanced?
2Cu + O
2
→ 2CuO
a.
mass of the reactants = mass of products
b.
mass of reactants = volume of products
c.
volume of reactants = mass of products
d.
volume of reactants = volume of products
Hint
