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Law of mass proportion

Total questions: 16

Worksheet time: 9mins

Name
Class
Date
1.

The percentage of copper and oxygen in samples of “CuO” obtained by different methods were found to be the same. This illustrates the law of:

a)

definite proportion

b)

Conservation of mass

c)

Multiple proportions

d)

Reciprocal proportions

2.
The dense, positively charged mass located in the center of the atom.
a)
nucleus
b)
proton
c)
isotope
d)
molecule
3.
Atoms of the same element must always have the same number of _________
a)
electrons
b)
neutrons
c)
isotopes
d)
protons
4.

The nucleus of an atom contains which subatomic particles?

a)

protons and electrons

b)

protons and neutrons

c)

electrons and neutrons

d)

protons, electrons, and neutrons

5.

Typically in an atom, which two subatomic particles are equal in number?

a)

protons and neutrons

b)

all subatomic particles are equal in number

c)

neutrons and electrons

d)

protons and electrons

6.
What types of particles are found in the cloud surrounding the atom's nucleus?
a)
Positively charged particles and negatively charged particles
b)
Negatively charged particles only
c)
Neutral particles and positively charged particles
d)
Positively charged particles only
7.

The law of definite proportions states that a given chemical compound always contains the same _ in the exact same _ by mass.

a)

elements, compounds

b)

elements, molecules

c)

elements, proportions

d)

proportions, elements

8.

Carbon 's mass is _.

a)

6

b)

12.01

c)

+/- 4

d)

2

9.

Oxygen's mass is _.

a)

8

b)

16

c)

-2

d)

2

10.

The mass of the compound CO2 is _.

a)

16

b)

28.01

c)

44.01

d)

56.02

11.

The percent by mass of carbon to oxygen in CO2 is _.

a)

100%

b)

33.3%

c)

72.7%

d)

27.3%

12.

The mass of an unknown element would be _ if the percentage of it in a 44.01 g compound was 27.29%.

a)

1.613 g

b)

12.01 g

c)

62.01 g

d)

72.71%

13.
Elements are made of 
a)
many types of atoms 
b)
the periodic table
c)
one type of atom 
d)
molecules 
14.
Two or more atoms chemically bonded together are called a
a)
atom
b)
element
c)
molecule
d)
mixture
15.
What is the atomic number?
a)
the number of protons
b)
the number of protons and neutrons
c)
the number of neutrons
d)
the number of protons and electrons
16.
What is the mass number defined as?
a)
the number of protons
b)
the number of protons and neutrons
c)
the number of neutrons
d)
the number of protons and electrons