Free Printable Chem B: Math in Formulas Review

1.

How many molecules of AlCl₃ are in 9.44 moles of AlCl₃?

a)

5.68 molecules

b)

5.68x10²⁴molecules

c)

0.705 molecules

d)

1.25x10²³molecules

2.

(0901) Avogadro’s number is:

a)

6.02 x 10²²

b)

6

c)

6.02 x 10²³

d)

3.01 x 10²³

3.

How many moles of methane (CH₄) are in 1.24 x 10²⁶ molecules of methane?

a)

6.02 x 10²³ moles

b)

7.46 x 10⁴⁸ moles

c)

978 moles

d)

206 moles

4.

How many moles are in 47 g of KCl?

a)

0.63 mole

b)

1.6 moles

c)

3500 moles

d)

120 moles

5.

Determine how many grams are in 0.36 moles of CCl₄ .

a)

150 g

b)

55 g

c)

0.0023 g

d)

2.2 g

6.

Suzie wants to know the mass of 1.55 moles of nitrogen trichloride. How do you set up the problem?

a)

$1.55\ mole\ NCl_3\ \times\ \frac{1\ mole}{molar\ mass\ of\ NCl_3\ \left(g\right)}=$

b)

$1.55\ mole\ NCl_3\ \times\ \frac{molar\ mass\ of\ NCl_3\ \left(g\right)}{1\ mole}=$

c)

$\ 1\ mole\ \times\ \frac{1.55\ mole\ NCl_3}{molar\ mass\ of\ NCl_3\left(g\right)}=$

d)

$\ molar\ mass\ of\ NCl_3\left(g\right)\ \times\ \frac{1\ mole}{1.55\ mole\ NCl_3}=$

7.

What is the percent by mass of Na in NaOH?

a)

40.00%

b)

2.53%

c)

22.91%

d)

57.48%

8.

What is the percent composition of benzene, C₆H₆?

a)

C = 50.00%

H = 50.%00

b)

C = 85.70%

H = 14.30%

c)

C = 92.24%

H = 7.76%

d)

C = 71.92%

H = 28.08%

9.

The mass % of aluminum in aluminum sulfate Al₂(SO₄)₃ is:

a)

12.93%

b)

45.70%

c)

7.89%

d)

35.94%

e)

15.77%

10.

A formula with the lowest whole # ratio of elements in a compound is called

a)

Molecular Formula

b)

Chemical Formula

c)

Empirical Formula

d)

Distance Formula

11.

What is the empirical formula for C₄H₆?

a)

CH

b)

CH₃

c)

C₂H₃

d)

C₄H₆

12.

Si₂F₆

Choose the correct empirical formula...

a)

SiF

b)

Si₂F₆

c)

SiF₃

d)

Si₆F₂

13.

A chemical formula that shows the actual # and kinds of atoms present in one molecule of a compound is called_________

a)

ionic formula

b)

covalent formula

c)

empirical formula

d)

molecular formula

14.

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)

Mg₃N₂

d)

MgN

15.

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180.18?

a)

CH₂O

b)

C₂H₄O₂

c)

C₄H₈O₄

d)

C₆H₁₂O₆

16.

Given the following: 41.79% Na, 19.43% P, and 38.78% O, determine the empirical formula.

a)

NaPO2

b)

Na2PO3

c)

Na3PO4

d)

NaPO4

17.

A compound has a molar mass of 92.11g/mol. Its percent composition is: 39.12% C, 8.77% H, and 52.11% O. What is the molecular formula for glycerol?

a)

C₂H₃O₂

b)

CH₂O

c)

C₂H₄O₂

d)

C₃H₈O₃

18.

Name the following ionic compound: MgSO₄*7H₂O

a)

magnesium sulfate * hexahydarte

b)

magnesium sulfate hexahydarte

c)

magnesium sulfate heptahydrate

d)

magnesium sulfate* heptahydrate

19.

Na₂CO₃ · 10H₂O is known as sodium carbonate ______

a)

Hydroxide

b)

Hydrate

c)

Decahydrate

d)

None of the above

20.

A 15.67 g sample of a hydrate of magnesium carbonate was heated to drive off the water. The mass was reduced to 7.58 g. What is the formula of the hydrate?

a)

MgCO₃ · 5H₂O

b)

MgCO₃ · 4H₂O

c)

MgCO₃ · 6H₂O

d)

MgCO₃ · 1H₂O

21.

A 4.4 gram sample of a hydrate was heated until the water of hydration was driven off. The anhydrous compound remaining had a mass of 3.3 grams. What is the percentage by mass of water in the hydrate?

a)

75%

b)

33%

c)

67%

d)

25%

22.

Cr(NO₃)₃ ⋅ 9H₂O

a)

chromium nitrate nonahydrate

b)

chromium nitrogen trioxide nonahydrate

c)

chromium (III) nitrate nonahydrate

d)

chromium (I) tritrioxide heptahydrate

23.

What is the best method for removing water from a hydrated compound?

a)

freezing

b)

filtration

c)

distillation

d)

heating

24.

Which of the following shows Magnesium Chloride Hexahydrate?

a)

MgCl₂ · 7 H₂O

b)

MgCl₂ ·4 H₂O

c)

MgCl₂ · 6 H₂O

d)

MgCl₂ ·5 H₂O

25.

How many grams are in 1.20 x 10²⁴ molecules of CO?

a)

28.2 grams

b)

55.8 grams

c)

6.02 grams

d)

1.2 grams

Chem B: Math in Formulas Review

Total questions: 25

Worksheet time: 1hrs 2mins

Similar Resources on Wayground