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Counting Atoms

Total questions: 20

Worksheet time: 11mins

Name
Class
Date
1.

Number of Carbon atoms in 2Na₂CO₃

a)
1
b)
2
c)
3
d)
5
2.
How many Elements are in the compound C2H8O ?
a)
2
b)
1
c)
3
d)
0
3.
How many total atoms are in the compound C2H8O ?
a)
11
b)
2
c)
8
d)
1
4.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
5.
How many Chlorine are in MgCl2?
a)
2
b)
1
c)
3
6.
How many elements are in C6H12O6?
a)
1
b)
2
c)
3
d)
4
7.
How many atoms are there TOTAL in:
H2SO4
a)
6
b)
5
c)
7
d)
3
8.

We breathe oxygen. Its chemical formula is O2. Is this formula an element or a compound?

a)

element

b)

compound

c)

neither

d)

both

9.

How many elements are in this chemical formula?

NaOH

a)

1

b)

2

c)

3

d)

4

10.

How many atoms are in the formula?

NaOH

a)

4

b)

3

c)

2

d)

1

11.

H2SO4

a)

H = 2, S = 4, O = 4

b)

H = 2, S = 1, O = 4

c)

H = 8, S = 4, O = 4

d)

H = 2, SO = 4

12.

How many atoms are present if there is no subscript following the element symbol?

a)

0

b)

2

c)

only 1

d)

1 million

13.

O is the chemical symbol for what element?

a)

Osmium

b)

Odell

c)

Oxygen

14.

Mrs. Powers and Mrs. Kitzel are baking a cake and they need to use baking soda. How many atoms of each element are in baking soda? (NaHCO3)

a)

6 Sodium atoms,

6 Hydrogen atoms,

6 Carbon atoms,

6 Oxygen atoms

b)

1 Sodium atom,

1 Hydrogen atom,

1 Carbon atom,

1 Oxygen atom

c)

1 Sodium atom

1 Hydrogen atom

1 Carbon atom

3 Oxygen atoms.

d)

1 Sodium atom, 1 Hydrogen atom, 1 Carbon atom

15.

Elliot and Beau are working on a chemistry project. They need to find out how many atoms of aluminum are in this formula: 2Al₂O₃


a)

2

b)

1

c)

4

d)

6

16.

What does the following represent?

a)

coefficient

b)

subscript

c)

elements

17.

Coefficients in chemical formulas...

a)

Multiply just the first atom

b)

Add to the subscripts at the end of the molecule

c)

Multiply elements without subscripts

d)

Multiply EVERYTHING!

18.

How many atoms of Hydrogen are in this compound?

a)

1

b)

2

c)

3

d)

4

19.
The red numbers in the image below represent ________
a)
subscripts
b)
coefficients
c)
I don't know, and don't want to try
d)
None of the answers are correct
20.

Which of the following is NOT a compound?

a)
HCl
b)
Cl
c)
NaCl
d)
CO2