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Mole concept (Calc)

Total questions: 12

Worksheet time: 1hrs 22mins

Name
Class
Date
1.

How many moles are 98.3 grams of aluminum hydroxide, Al(OH)3? (Atomic mass of Al = 27, H= 1, O = 16)

a)

1.26 moles

b)

0.8 moles

c)

7,673.4 moles

d)

150 moles

2.

How many molecules are contained in 25 g of NaBr? (Atomic mass of Na = 23, Br = 80)

a)

102.96 molecules

b)

0.24 molecules

c)

1.45x1023 molecules

d)

2.34 x 1020molecules

3.
How many moles are in 3.01 x 1022 atoms of magnesium?
a)
0.0500 moles
b)
1.81 x 1046 moles
c)
5.00 x 1021 moles
d)
5.00 moles
4.
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
a)
Mg4N3
b)
MgN2
c)
Mg3N
d)
MgN
5.

What is the empirical formula for thr compound, CxHyOz , if the ratio C: H: O equal to 2: 2.5 : 1

a)

C2H2O1

b)

C2H5O1

c)

C4H5O2

d)

C3H2O2

6.

The empirical formula for hydrocarbon A is C2H7O. If the molar mass of the hydrocarbon is 141 g/mol, determine the molecular formula for this hydrocarbon.

a)

C2H7O

b)

C4H14O2

c)

C6H21O3

d)

C8H28O4

7.

Calculate the percentage of composition by mass of oxygen in Al(HCO3)3.

a)

22.86 %

b)

68.57 %

c)

78.26 %

d)

40.50 %

8.

Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.

a)

NaPO2

b)

Na2PO3

c)

Na3PO4

d)

NaPO4

9.

Which of the following statement are true about the formula of dinitrogen monoxide, N2O?

a)

The relative molecular mass is 28.

b)

One molecule of N2O consists of one nitrogen atom and one oxygen atom.

c)

One mole of N2O contains 6.02 x 1023 atoms of nitrogen.

d)

One mole of N2O consists of two mole of nitrogen atom and one mole of oxygen atom.

10.

What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?

a)

C3H8

b)

CH4

c)

C2H2

d)

C4H10

11.

1. Ibuprofen consists of carbon, hydrogen and oxygen. When 5.000 g sample of ibuprofen is burned in oxygen, 13.86 g of CO2 and 3.926 g of water are obtained. What is the empirical formula of ibuprofen?

a)

C12H17O2

b)

C13H18O2

c)

C14H19O2

12.

The combustion of 0.202 g of an organic compound produces 0.361 g of CO2 and 0.147 g of water. Determine the molecular formula of the compound if it consists of C, H and O and has the molar mass of 148 g/mol.

a)

C3H6O2

b)

C6H12O2

c)

C6H12O4

d)

C6H12O