Free Printable final exam chem 1 a

1.

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

2.

Which of the following is considered an empirical formula?

a)

CH₃COOH

b)

C₆H₁₂O₆

c)

H₂O

3.

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

a)

SO

b)

SO2

c)

SO3

d)

SO4

4.

Which pair has the same empirical formula?

a)

NaCrO₄ and Na₂Cr₂O₇

b)

C₂H₄O₂ and C₆H₁₂O₆

c)

C₃H₆O₃and C₂H₆O₂

d)

CH₄ and C₂H₆

5.

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

6.

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

7.

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

a)

C₂H₃O₂

b)

CH₂O

c)

C₂H₄O₂

d)

C₃H₈O₃

8.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

What is the empirical formula of J?

a)

C₄HNO₂

b)

CH₂N₂O

c)

C₂HNO₂

d)

CHNO

9.

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

10.

Which one is the empirical formula?

C₄H₆

a)

CH

b)

CH₃

c)

C₂H₃

d)

C₄H₆

11.

What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?

a)

29%

b)

43%

c)

57%

d)

73%

12.

What percentage of the total atomic mass of carbon monoxide (CO) is composed of oxygen?

a)

29%

b)

43%

c)

57%

d)

73%

13.

What percentage of the total atomic mass of lithium phosphide (Li₃P) is composed of phosphorus?

a)

13%

b)

29%

c)

40%

d)

60%

14.

What is the molar mass of table salt (NaCl)?

a)

116.886 g/mol

b)

35.453 g/mol

c)

22.990 g/mol

d)

58.443 g/mol

15.

What is the molar mass of NaOH?

a)

40 g/mol

b)

38.989 g/mol

c)

23.998 g/mol

d)

57.004 g/mol

16.

What is the molar mass of CO₂?

a)

12

b)

16

c)

32

d)

44

17.

What is the percent by mass of fluorine in CaF₂(gram-formula mass = 78 g/mol)?

a)

24%

b)

49%

c)

51%

d)

65%

18.

Find the percent composition of Cu₂S?

a)

%Cu= 67.987 %S= 32.013

b)

%Cu= 79.854 %S= 20.145

c)

%Cu= 35.946 %S= 64.054

19.

How to calculate molar mass of H₂O?

a)

2+16=18

b)

1+16=17

c)

2+32=34

d)

1+31=32

20.

Find the percentage composition of Mg in Mg₃(PO₄)₂.

a)

27.48% Mg

b)

43.11% Mg

c)

16.00% Mg

d)

12.63% Mg

21.

Which list of number of atoms in Mg(NO₃)₂ is right?

a)

Mg : 1--NO : 6

b)

Mg : 1-- N : 6--O: 6

c)

Mg : 1-- N: 1-- O: 5

d)

Mg : 1-- N: 2-- O: 6

22.

What is the percentage of OH^–in Ca(OH)₂?

a)

45.9%

b)

75%

c)

66.6%

d)

90.1%

23.

In the reaction represented by the equation CH4(g) + O2(g) ----> CO₂(g) + H₂O(g), a mass of 125 g CH₄is reacted with excess oxygen. The expression:

$125\ g\ CH_{4\ }\times\frac{1\ mol\ CH_4}{16.05\ g\ CH_4}\times\frac{2\ mol\ H_2O\ }{1\ mol\ CH_4}\times\frac{18.20\ g\ H_2O}{1\ mol\ H_2O}$

is used to calculate the:

a)

mass of oxygen redacted.

b)

mass of carbon dioxide produced.

c)

mass of water produced.

d)

none of the above.

24.

What is the mole ratio of H2O to H3PO4 in the following chemical equation?

$P_4O_{10}+6H_2O\ \rightarrow\ 4H_3PO_4$

a)

1 to 6

b)

3 to 2

c)

4 to 6

d)

2 to 3

25.

Knowing the mole ratio of a reactant and product in a chemical reaction would allow you to determine:

a)

the energy released in the reaction.

b)

the speed of the reaction.

c)

whether the reaction is reversible.

d)

the mass of the product produced from a known mass of reactant.

26.

In the equation $6CO_2+6H_2O\ \rightarrow\ C_6H_{12}O_6+6O_2$ the mole ratio of water to oxygen is:

a)

2 : 1

b)

1 : 1

c)

3 : 2

d)

6 : 8

27.

In the equation $Al_2\left(SO_4\right)3+3Ca\left(OH\right)_2\ \rightarrow\ 3CaSO_4\ +2Al\left(OH\right)_3$ , , the mole ratio of calcium hydroxide to aluminum hydroxide is:

a)

1 : 3

b)

2 : 3

c)

1 : 1

d)

3 : 2

28.

For the reaction represented by the equation $N_2+3H_{2\ }\rightarrow\ 2NH_3$ , how many moles of nitrogen (N2) are required to produce 18 grams of ammonia (NH3)?

a)

0.9 mol

b)

18 grams

c)

0.53 mol

d)

36 grams

29.

The most steps are required to solve stoichiometry problems when the reactant is given in grams and the product is sought in

a)

moles.

b)

grams.

c)

liters.

d)

number of atoms.

30.

For the reaction represented by the equation $Pb\left(NO_3\right)_2+2KI\ \rightarrow\ PbI_2+2KNO_3$ how many moles of lead iodide $\left(PbI_2\right)$ are produced of 300 grams potassium iodide $\left(KI\right)$ when $Pb\left(NO_3\right)_2$ is in excess?

a)

114.78 mol PbI₂

b)

0.904 grams PbI₂

c)

0.904 mol PbI₂

d)

114.78 grams PbI₂

31.

For the reaction represented by the equation $2KClO_3\rightarrow\ 2KCI+30_2$ how many grams of potassium chlorate are required to produce 160. g of oxygen?

a)

408 g KClO₃

b)

804 g KClO₃

c)

598 g KClO₃

d)

There is not enough information.

32.

Which of the following would have more mass?

a)

1 mole of Li

b)

1 mole of Au

c)

1 mole of Si

d)

None, all are equal

33.

Vitamin C, also known as ascorbic acid, is water soluble and cannot be produced by the human body. Each day, a person's diet should include a source of Vitamin C, such as orange juice. Ascorbic acid has a molecular formula of C₆H₈O₆ and a molar mass of 176 grams per mole.

Determine the number of moles of vitamin C in an orange that contains 0.171 grams of vitamin C.

a)

30.1 moles

b)

1030 moles

c)

.000971 moles

d)

.0001 mole

34.

Calculate the number of moles in 55g of copper chloride (CuCl₂)

a)

0.41 moles

b)

0.82 moles

c)

1.6 moles

d)

.20 moles

35.

What is the mass of 0.75 moles of (NH₄)₃PO₄?

a)

0.0044 g

b)

91 g

c)

110 g

d)

74 g

36.

Which has more molecules?

a)

1 mole H₂O

b)

1 mole Al(OH)₃

c)

1 mole NaCl

d)

There are all the same

37.

How many molecules are present in 135 g of Teflon C₂F₄

a)

6.13 x 10²³ molecules

b)

5.13 x 10²³ molecules

c)

8.13 x 10 ²³ molecules

d)

9.13 x 10²³ molecules

38.

Which of the following would have the highest number of moles?

a)

4g CO₂

b)

15g H₂O

c)

22g NaCl

d)

100g AgCl

39.

What is the molar mass of calcium hydroxide, Ca(OH)₂?

a)

74.1 g/mole

b)

57.1 g/mole

c)

58.1 g/mole

d)

57.1 u

40.

How many particles are in 13.5 grams of Beryllium?

a)

1.5 particles

b)

9 particles

c)

4x10²³ particles

d)

9x10²³ particles

41.

Calculate the number of moles of Aluminum in a 2.04 mole sample of aluminum oxide, Al₂O₃.

a)

2.04 moles

b)

4.08 moles

c)

6.12 moles

d)

1.02 moles

42.

Find the molar mass of $H_2$

a)

1.01g

b)

2.02g

c)

1.02g

d)

2.01g

43.

Find the molar mass of $CaCO_3$

a)

100.09g

b)

100g

c)

100.2g

d)

101g

44.

Find the number of moles in 75 grams of $NaHCO_3$

a)

89mol

b)

0.90mol

c)

0.89mol

d)

84mol

45.

Find the molar mass of $NH_3$

a)

17.04g

b)

17g

c)

14.07g

d)

17.03g

46.

Find the number of moles in 20 grams of $NH_3$

a)

17.04mol

b)

1.17mol

c)

11.7mol

d)

17.03mol

47.

2Al + 6HCl --> 2AlCl₃ + 3H₂

Aluminium reacts with hydrochloric acid. How many grams of aluminum are necessary to produce 11 L of hydrogen gas at STP?

a)

13

b)

8.8

c)

0.99

d)

1.0

48.

Mg₃N₂ + 3H₂O ––> 3 MgO + 2NH₃

If 10.3 g of magnesium nitride is used, what volume of ammonia gas would be collected at 20˚C and 0.989 atm?

a)

4.9 L NH₃

b)

4.96 L NH₃

c)

0.261 L NH₃

d)

0.26 L NH₃

49.

1Mg + 2H₂O --> Mg(OH)₂ + H₂

What volume of hydrogen will be produced at STP by the reaction 67.3 g of magnesium?

a)

62.0 L

b)

0.12 L

c)

2.77 L

d)

1.15 L

50.

What is the mole ratio in the following reaction:
2CO + O₂→ 2CO₂

a)

2:1:2

b)

1:1:1

c)

1:2:1

d)

Have no clue what a mole ratios is!!

51.

1 mole of any gas at STP has a volume of ______________________.

a)

22.4 liters

b)

44.2 liters

c)

6.02 x 10²³ liters

d)

2.4 liters

52.

In a chemical reaction, the mass of reactants ___.

a)

is less than the mass of products

b)

is greater than the mass of products

c)

has no relationship to the mass of products

d)

is equal to the mass of products

53.

When calculating molar mass for an element, which number do you need to look at on the periodic table?

a)

Atomic number

b)

Atomic Mass

c)

Atomic particles

d)

Avogardo's Number

54.

The calculation of the relationships between different molecules in a reaction is the definition of __________________.

a)

physics

b)

algebra

c)

stoichiometry

d)

language arts

55.

Before you begin any stoichiometry problem, you must always start with this.

a)

A periodic table.

b)

A calculator.

c)

A balanced chemical equation.

d)

All of the above are helpful.

56.

The process of comparing units is called ____________________.

a)

stoichiometry

b)

dimensional analysis

c)

algebra

d)

social studies

57.

What conversion factor do you always use in stoichiometry problems?

a)

reciprocal of the molar mass of a substance

b)

molar mass of a substance

c)

mole ratio

d)

molar volume of a gas

58.

What is the number of atoms per molecule for each diatomic molecule?

a)

1

b)

2

c)

3

d)

4

e)

5

59.

When you balance a chemical equation, you are following:

a)

the Law of Conservation of Mass

b)

the Law of Conservation of Energy

c)

the Law of Motion

d)

atomic theory

e)

Coulomb's Law of Attraction

60.

When balancing, what part of a chemical equation are you potentially changing?

a)

coefficients in front of chemical formulas

b)

chemical formulas derived from the element boxes

c)

subscripts within the chemical formulas

d)

the ions (oxidation states) of polyatomic ions

61.

What is the mole ratio of Aluminum to Oxygen in the chemical reaction:

Al + O₂--> Al₂O₃

a)

1:1

b)

2:3

c)

4:2

d)

4:3

e)

3: 4

62.

CH₄ + 2O₂ → CO₂ + 2H₂O

24 grams of CH₄ was added to the above reaction. Calculate the theoretical yield of CO₂.

a)

66 grams

b)

130 grams

c)

33 grams

d)

8.72

63.

The ______________ yield is the maximum amount of product possible in a reaction. This determines the amount of product that should be produced in a perfect setting

a)

Percent

b)

actual

c)

stoichiometry

d)

theoretical

64.

2 Fe₂O₃ + C → Fe + 3 CO₂

You add 28.0 grams of carbon. You find the actual yield to be 181.2 grams of CO₂. What is the percent yield of CO₂? (Hint: calculate theoretical yield of CO₂ first)

a)

58.8%

b)

308%

c)

6440%

d)

15.5%

65.

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.

a)

1.16%

b)

116%

c)

85%

d)

76%

66.

In a lab, a scientist calculates she should produce 12.3 grams of product in her experiment. When she is finished collecting her product it weighs 10.1 grams. What is her percent yield?

a)

82.0%

b)

0.820%

c)

10.1 %

d)

100.%

final exam chem 1 a

Total questions: 66

Worksheet time: 2hrs 13mins

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