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Molar Mass & Percent Composition

Total questions: 10

Worksheet time: 12mins

Name
Class
Date
1.

Which of the following compounds contains the most oxygen by mass?

a)

H2O

b)

H2O2

c)

H3O+

d)

none because they have equal percentage composition 

2.

Which between carbon monoxide and carbon dioxide has a greater carbon content by mass?

a)

carbon monoxide

b)

carbon dioxide

c)

none because they have equal percentage composition 

d)

cannot be determined 

3.

The molar mass of this compound is computed to be 74.14g/mol. 

Identify this alcohol.

a)

ethanol (C2H6O)

b)

propanol (C3H8O)

c)

butanol (C4H10O) 

d)

pentanol (C5H12O)

4.

An unlabeled bottle of alcohol produces the following composition: 

C = 59.94% H = 13.44% O = 26.62%.

Which alcohol was analyzed?

a)

ethanol (C2H6O)

b)

propanol (C3H8O)

c)

butanol (C4H10O) 

d)

pentanol (C5H12O)

5.

The A compound with a molar mass of 92.16g/mol is known to have the same empirical formula as this alcohol. Which alcohol is being described?

a)

ethanol (C2H6O)

b)

propanol (C3H8O)

c)

butanol (C4H10O) 

d)

pentanol (C5H12O)

6.

Prof. X wanted the alcohol that has the highest oxygen content. Which alcohol should you give him?

a)

ethanol (C2H6O)

b)

propanol (C3H8O)

c)

butanol (C4H10O) 

d)

pentanol (C5H12O)

7.

Arrange the elements of this common herbicide, C₉H₉ClO₃,  according to increasing percent composition.

a)

Cl<O<H<C 

b)

H<O<Cl<C

c)

H<Cl<O<C

d)

Cl<H<O<C

8.

The mass of each element per 100 mass unit of compound is called __________.

a)

percent composition

b)

molar mass

c)

mole ratio

d)

molecular formula

9.

Glycerol has a chemical formula of CxH8O3 and has a molar mass of 92.09g/mol. 

How many carbons does glycerol have?

a)

1

b)

2

c)

3

d)

4

10.

Glycerol has a chemical formula of CxH8O3 and has a molar mass of 92.09g/mol. 

What percent of glycerol is carbon?

a)

66.66%

b)

39.10%

c)

21.42%

d)

3.25%