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Counting Atoms in Chemical Formulas

Total questions: 36

Worksheet time: 1hrs 14mins

Name
Class
Date
1.

How many oxygen atoms (O) are in a CO2 molecule?

(a)  

2.

How many Oxygen atoms (O) are in a  molecule  of 7CO2

(a)  

3.

How many Hydrogen atoms (H) are in a molecule of 2H2O?

(a)  

4.

How many COMPOUNDS of sugar are there 3C6H12O6?

(a)  

5.

Which is the correct formula for:
 six hydrogen (H)
two sulfur (S)
eight oxygen (O)

a)

2H3SO4

b)

2HSO4

c)

2H4S3O

d)

2H2O

6.

How many atoms are there TOTAL in:
CaH2(SO4)2

(a)  

7.

How many Oxygen atoms (O) are in a molecule of 2Ca3(CO2)4

(a)  

8.

How many carbon atoms (C) are in a 3NaCO2 molecule?

(a)  

9.

How many Hydrogen atoms (H) are in a molecule of 5Li3H6O?

(a)  

10.

How many atoms of carbon (C) are in C6H12O6?

(a)  

11.
Which is the correct formula for:
 three hydrogen (H)
one sulfur (S)
four oxygen (O)
a)
H3SO4
b)
HSO4
c)
H4S3O
d)
H2O
12.
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
13.
The blue numbers in the image below represent ________
a)
I don't know, and don't want to try
b)
coefficients
c)
subscripts
d)
none of the answers are correct
14.

How many atoms are there TOTAL in:

H2SO4

(a)  

15.

How many Sodium (Na) are in 6NaCl?

(a)  

16.

How many oxygen atoms are in 6H2O ?

a)

1

b)

2

c)

6

17.

How many chlorine atoms are in NaClO4 ?

a)

1

b)

2

c)

4

18.

How many hydrogen atoms are in Pb(HCO3)4 ?

a)

1

b)

3

c)

4

19.

How many sulfur atoms are in H2SO4 ?

a)

1

b)

2

c)

4

20.

How many molecules are represented by 2C6H12O6 ?

(a)  

21.

How many atoms are in one molecule of C12H22O11 ?

(a)  

22.

How many atoms/ions are in one formula unit of Zn(C2H3O2)2 ?

(a)  

23.

Match the description with the number

3Mn2(CO3)7

a)
90
1.

Total number of atoms in the compound

b)

21

2.

Number of carbon atoms

c)

63

3.

Number of oxygen atoms

d)

6

4.

Number of Manganese atoms

e)

3

5.

Number of compounds

24.

Match the numbers with the correct description

4N2(SO4)3

a)
8
1.

Number of Nitrogen atoms

b)

12

2.

Number of Sulfur atoms

c)

48

3.

Number of Oxygen atoms

d)

68

4.

Total number of atoms in the compound

e)

4

5.

Number of compounds present

25.

How many carbon atoms are in 3CH3CH3CH2CH2CH2CH3 ?

(a)  

26.

Match the numbers with the descriptions

3Pb4(NO3)2

a)
3
1.

Number of compounds

b)

12

2.

Number of Lead atoms

c)

6

3.

Number of Nitrogen atoms

d)

18

4.

Number of Oxygen atoms

e)

36

5.

Total number of atoms in the compound

27.

How many elements of carbon (C) are in 6C6H12O6?

(a)  

28.

3(NH₄)₂CrO₄

Number of N: ​ ​ (a)  

Number of H: ​ (b)  

Number of Cr: ​ (c)  

Number of O: ​ (d)  

Choose from the below words
6
24
3
12
4
8
1
2
9
29.

How many elements are in 2 C6H12O7? (a)  

How many C: ​ (b)  

How many H: ​ (c)  

How many O: ​ (d)  

How many TOTAL atoms: ​ (e)  

Choose from the below words
3
12
24
14
50
7
6
25
52
60
30.

How many carbon atoms are there?

a)

2

b)

3

c)

8

d)

16

31.

How many atoms of oxygen are there?

a)

0

b)

1

c)

2

d)

3

32.

C3H5(NO3)3

a)

C = 3, H = 5, N = 3, O = 9

b)

C = 3, H = 5, N = 1, O = 9

c)

C = 9, H = 15, N = 3, O = 9

d)

C = 9, H = 15, N = 1, O = 3

33.

The compound Fe2(CO3)3 contains how many atoms of each element?

a)

2 iron, 1 carbon, 6 oxygen

b)

2 iron, 3 carbon, 6 oxygen

c)

6 iron, 3 carbon, 9 oxygen

d)

2 iron, 3 carbon, 9 oxygen

34.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
35.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
36.
Number of N in (NH₄)₂CrO₄
a)
1
b)
2
c)
8
d)
16