Deck 2: The Mole

Question 1

Which of the following contains the largest number of hydrogen atoms?

A) 1 mol of H₂O
B) 0.5 mol of NH₃
C) 0.20 mol of CH₄
D) 0.20 mol of C₆H₁₂O₆
E) 0.01 mol of H₃PO₄

Answer 1

0.20 mol of C₆H₁₂O₆

Question 2

How many platinum atoms does 1.00 g of pure platinum contain?

A) 195 Pt atoms
B) 3.09 x 10²¹ Pt atoms
C) 6.17 x 10²¹ Pt atoms
D) 1.95 x 10²³ Pt atoms
E) 6.02 x 10²³ Pt atoms

Answer 2

3.09 x 10²¹ Pt atoms

Question 3

There are 16 ounces in a lb and 2.20 lbs in a kg. What would be the value of Avogadro's number if this constant was defined as the number of ¹²C atoms in 12 ounces of ¹²C?

A) 0.171 x 10²³
B) 6.02 x 10²³
C) 28.4 x 10²³
D) 171 x 10²³
E) 2050 x 10²³

Answer 3

171 x 10²³

Question 4

If the atomic weight of platinum is 195.08 g/mol, what is the mass in grams of a single platinum atom?

A) 1.62 x 10^-22 g
B) 3.24 x 10^-22 g
C) 5.13 x 10^-3 g
D) 195.08 g
E) none of the above

Question 5

What is the molar mass of an element for which a single atom weighs
3.95 x 10^-22 g?

A) 6.56 x 10^-46
B) 1.31 x 10^-45
C) 3.95 x 10^-22
D) 238
E) 476

Question 6

What is the mass in grams of 0.250 moles of magnesium?

A) 0.0103 g
B) 6.08 g
C) 13.8 g
D) 97.2 g
E) none of these

Question 7

Which of the following represents the largest number of moles of molecules?

A) 10 g NH₃
B) 10 g N₂
C) 10 g Cu
D) 10 g Br₂
E) all of these contain the same number of moles

Question 8

How many $\textbf{ moles }$ of oxygen $\textbf{ atoms }$ are in 0.500 grams of CO₂?

A) 0.500 x 10 ^{- 2}
B) 1.00
C) 0.250
D) 1.14 x 10 ^{- 2}
E) 2.27 x 10 ^{- 2}

Question 9

Arrange the following in order of increasing mass:
(1) one F atom
(2) 1 x 10 ^{- 20} mol of F
(3) 1 x 10 ^{- 20} g of F
(4) one F₂ molecule

A) 1 < 2 < 3 < 4
B) 1 < 4 < 3 < 2
C) 3 < 1 < 2 < 4
D) 2 < 1 < 3 < 4
E) none of these

Question 10

What is the molar mass of barium nitrate, Ba(NO₃)₂?

A) 261 g/mole
B) 199 g/mole
C) 213 g/mole
D) 167 g/mole
E) none of these

Question 11

What is the mass in grams of 0.125 moles of calcium chloride, CaCI₂.

A) 111 g
B) 13.9 g
C) 8.88 x 10² g
D) 1.13 x 10^-3 g
E) 41.7 g

Question 12

How many moles of phosphorus atoms are in 100 grams of P₄S₁₀?

A) 4.00
B) 4.00 x 10²
C) 0.225
D) 0.487
E) 0.900

Question 13

Determine the number of moles in 12.5 g of carbon tetrachloride, CCl₄.

A) 8.13 x 10^-2 mol
B) 12.3 mol
C) 1.92 x10³ mol
D) 7.53 x 10²⁴ mol
E) none of these

Question 14

What is the mass in grams of of 0.158 moles of Cu(NO₃)₂?

A) 2.96 x 10¹g
B) 8.42 x 10^-4 g
C) 1.19 x 10³ g
D) 12.3 g
E) none of these

Question 15

Calculate the number of moles in 15.0 grams of NaOH.

A) 40.0 mol
B) 6.00 x 10² mol
C) 2.67 mol
D) 0.375 mol
E) none of these

Question 16

Which of the following contains more atoms of nitrogen, 100 moles of NH₃ or 100 moles of N₂O₅? Explain your reasoning without showing calculations.

Question 17

How many moles of Na₂S are found in 20.0 grams of sodium sulfide, Na₂S?

A) 0.256 moles
B) 0.364 moles
C) 2.75 moles
D) 3.90 moles
E) none of these

Question 18

Calculate the number of $\textbf{ nitrogen atoms }$ in 0.125 $\textbf{ moles }$ of barium nitrate, Ba(NO₃)₂.

A) 2.00 atoms
B) 0.125 atoms
C) 0.250 atoms
D) 1.51 x 10²³ atoms
E) 7.53 x 10²² atoms

Question 19

What is the molecular weight of aspirin, C₉H₈O₄?

A) less than 50 amu
B) between 50 and 80 amu
C) between 80 and 120 amu
D) between 120 and 160 amu
E) more than 160 amu

Question 20

Cocaine is extracted from the leaves of plants of the species E. coca, whereas chocolate is extracted from the seeds of the species E. cacao. (Never confuse one with the other!) Calculate the molar mass of cocaine, assuming a molecular formula of C₁₇H₂₁NO₄.

A) between 0 and 100 g/mol
B) between 100 and 250 g/mol
C) between 250 and 300 g/mol
D) between 300 and 350 g/mol
E) more than 350 g/mol

Question 21

What is the mass in amu of one molecule of sucrose (cane sugar) that has the formula: C₁₂H₂₂O₁₁?

A) less than 100 amu
B) between 100 and 150 amu
C) between 150 and 250 amu
D) between 250 and 350 amu
E) more than 350 amu

Question 22

What is the mass in grams of one molecule of CO₂?

A) 4.6 x 10^-23 g
B) 7.3 x 10^-23 g
C) 28 g
D) 44 g
E) none of the above

Question 23

The drug for which more prescriptions - and more bad jokes - were written than any drug released recently has the scientific name Sildenafil citrate and the trade name Viagra™. The structure of Sildenafil is shown below.
When this structure is translated into a chemical formula we get a molecular formula of C₂₂H₃₂N₆O₄S. Calculate the molecular weight of this compound.

A) between 100 and 200 g/mol
B) between 200 and 300 g/mol
C) between 300 and 400 g/mol
D) between 400 and 500 g/mol
E) more than 500 g/mol

Question 24

Let's consider another "miracle drug" with the scientific name orlistat, which is marketed by Roche Pharmaceuticals as Xenical. The formal chemical name for Xenical is (s)-2-formylamino-4-methyl-pentanoic acid (s)-1-[[(2S, 3S)-3-hexyl-4-oxo-2-oxetanyl] methyl]-dodecyl ester. Its structure is shown below. The molecular formula for this wonder diet drug that is supposed to block the uptake of fat is C₂₉H₃₅NO₅. Calculate the molecular weight of this compound.

A) between 100 and 200 g/mol
B) between 200 and 300 g/mol
C) between 300 and 400 g/mol
D) between 400 and 500 g/mol
E) more than 500 g/mol

Question 25

If you eat too much fat while taking Xenical, you're going to be very, very "uncomfortable." You can avoid this problem, of course, by taking the other new diet drug, Sibutramine hydrochloride monohydrate, which is marketed by a subsidiary of BASF as Meridia. Meridia is a neurotransmitter that inhibits the uptake of other neurotransmitters, such as dopamine, norepinephrine, and serotonin. It therefore tends to depress one's appetite and is being studied as a possible treatment for depression. Elemental analysis suggests that this compound is 72.96% C, 9.36% H, 12.67% Cl, and 5.01% N by weight. What is the total number of C, H, N and Cl atoms in the molecular formula of this compound if the molecular weight is 279.85 g/mol?

A) 10 or less
B) between 11 and 20
C) between 21 and 30
D) between 31 and 40
E) between 41 and 50

Question 26

ADM (Archer Daniels Midland) the self-proclaimed "Supermarket to the World" has been in trouble for allegedly fixing the price of lysine, an amino acid that is often deficient in vegetarian diets. Lysine is 19.16% N by weight and each molecule contains two nitrogen atoms. Calculate the molecular weight of lysine.

A) less than 100 g/mol
B) between 100 and 150 g/mol
C) between 150 and 250 g/mol
D) between 250 and 350 g/mol
E) more than 350 g/mol

Question 27

Calculate the number of carbon atoms in a mole of sucrose, C₁₂H₂₂O₁₁.

A) 12 atoms
B) 6.02 x 10²³ atoms
C) 6.62 x 10²⁴ atoms
D) 7.22 x 10²⁴ atoms
E) 1.3 x 10²⁵ atoms

Question 28

Calculate the number of chlorine atoms in 10.4 grams of chloroform, CHCl₃.

A) 5.25 x 10²² atoms
B) 1.05 x 10²³ atoms
C) 1.57 x 10²³ atoms
D) 2.10 x 10²³ atoms
E) 2.07 x 10²⁵ atoms

Question 29

Sodium tripolyphosphate, Na₅P₃O₁₀, is added to detergents to increase their cleaning power. Calculate the number of phosphorus atoms in 0.325 moles of this compound.

A) 6.52 x 10²² atoms
B) 1.96 x 10²³ atoms
C) 5.87 x 10²³ atoms
D) 6.02 x 10²³ atoms
E) none of the above

Question 30

Acetic acid, C₂H₄O₂, is the substance that makes vinegar taste sour. What is the % mass of carbon in acetic acid?

A) 20%
B) 25%
C) 35%
D) 40%
E) none of these

Question 31

Calculate the % mass of sodium in sodium sulfate, Na₂SO₄.

A) 16%
B) 23%
C) 32%
D) 54%
E) 67%

Question 32

A hydrate is heated to determine the % water by mass in the hydrate. During heating of the hydrate a small chip is broken off of the lid of the crucible and falls to the lab bench without being noticed. What effect will this have on the calculated value of the % water by mass?

A) It will be high.
B) It will be low.
C) It will not affect the results.
D) It could be either high or low.

Question 33

Which of the following nitrogen-containing compounds would supply the most nitrogen per gram of fertilizer?

A) iron azide, Fe(N₃)₂, MW = 140 g/mol
B) sodium azide, NaN₃, MW = 65 g/mol
C) potassium nitrite, KNO₂, MW = 85.1 g/mol
D) potassium azide, KN₃, MW = 81.1 g/mol
E) There is not enough information to answer this problem.

Question 34

Apatite is a mineral that is found in tooth enamel. When fluoride toothpastes are used, this mineral is converted to fluoroapatite, which is much harder and therefore more resistant to decay. What is the percent by weight of fluorine in fluoroapatite, Ca₅(PO₄)₃F?

A) between 0 and 0.1%
B) between 0.1% and 1%
C) between 1% and 3%
D) between 3% and 5%
E) more than 5%

Question 35

In March of 2007 a number of pets were sickened or killed by pet food contaminated with the chemical melamine which is used in the manufacture of certain plastics. It is thought that the melamine was added to make a pet food additive appear to have more protein than it really did. Protein content is determined by measuring nitrogen content of food since protein is the main source of nitrogen in food. What is the % by mass of nitrogen in melamine which has the formula C₃H₆N₆?

A) 66.6%
B) 61.2%
C) 11.1%
D) 82.3%
E) Insufficient information is given to find the %N by mass.

Question 36

In March of 2007 a number of pets were sickened or killed by pet food contaminated with the chemical melamine (C₃H₆N₆) which is used in the manufacture of certain plastics. It is thought that the melamine was added to make a pet food additive appear to have more protein than it really did. Protein content is determined by measuring the %N by mass in food because protein is the main source of nitrogen in food. Proteins are composed of amino acids so the %N by mass of a protein reflects the %N of the individual amino acids. Alanine is a typical amino acid and has the formula C₃H₇NO₂. Calculate the %N by mass in melamine and alanine. Why would adding a small amount of melamine make something appear to have a high protein content?

Question 37

Determine the empirical formula of a compound containing 59.0% Na and 41.0% O by mass.

A) NaO
B) Na₂O
C) NaO₂
D) Na₂O₃
E) none of these

Question 38

Cobalt oxide used in glazing pottery contains 71.06% cobalt and 28.94% oxygen by mass. What is the empirical formula of this cobalt oxide?

A) CoO
B) Co₂O
C) CoO₃
D) Co₂O₃
E) Co₃O₄

Question 39

Calculate the molecular weight of the oxygen-carrier protein hemoglobin if
This protein is 0.335% Fe by weight and each protein molecule contains four
Iron atoms.

A) less than 1000 grams per mole
B) between 1000 and 10,000 grams per mole
C) between 10,000 and 50,000 grams per mole
D) between 50,000 and 100,000 grams per mole
E) more than 100,000 grams per mole

Question 40

Calculate the number of carbon atoms in the empirical formula of nicotine if this compound is 74.0% C, 8.7% H, and 17.3% N by weight.

A) 3 atoms
B) 4 atoms
C) 5 atoms
D) 7 atoms
E) 10 atoms

Question 41

Glucose (blood sugar), acetic acid, and formaldehyde are all 40.0% C, 6.76% H, and 53.3% O by weight. Calculate the total number of carbon, hydrogen, and oxygen atoms in the empirical formula for these compounds.

A) 3
B) 4
C) 5
D) 6
E) 9

Question 42

A compound that is 43.64% P and 56.36% O by weight has a molecular
Weight of 283.88 g/mol. What is the molecular formula of this compound?

A) PO₄
B) P₂O₃
C) P₂O₅
D) P₄O₁₀
E) none of the above

Question 43

A mixed oxide of potassium and vanadium is 28.3% by weight potassium and 37.0% by weight vanadium. What is the empirical formula?

A) KV
B) KVO
C) K₂V₃O
D) K₃V₃O
E) KVO₃

Question 44

The chief ore of manganese is an oxide known as pyrolusite, which is 36.8% O and 63.2% Mn by weight. Which of the following is the correct empirical formula for pyrolusite?

A) MnO
B) MnO₂
C) Mn₂O₃
D) MnO₃
E) Mn₂O₇

Question 45

Nitrogen combines with oxygen to form a variety of compounds. One of these compounds is called nitrous oxide or "laughing gas." What is the formula of nitrous oxide if this compound is 63.65% N and 36.35% O by weight?

A) N₂O
B) NO
C) NO₂
D) N₂O₃
E) N₂O₅

Question 46

What is the atomic weight of a metal that forms an oxide, M₂O₃, which is 17.29% oxygen by weight?

A) 38.3 g/mol
B) 57.4 g/mol
C) 76.6 g/mol
D) 115 g/mol
E) 229 g/mol

Question 47

Cisplatin is a commercial antitumor drug that contains 65.0% Pt, 23.7% Cl, 9.3% N and 2.0% H by weight. What is the ratio of H to Pt atoms in the empirical formula of this compound?

A) 1:1
B) 2:1
C) 3:1
D) 4:1
E) 6:1

Question 48

What is the atomic weight in amu of the element that forms a fluoride, M₂F₄, which is 73.1% fluorine by weight?

A) 14.0 amu
B) 16.0 amu
C) 28.0 amu
D) 32.0 amu
E) none of these

Question 49

What is the empirical formula of a compound that contains C, H, and O if the compound is 40.00% C and 6.71% H by weight?

A) CHO
B) CH₂O
C) CH₃O
D) CH₄O
E) none of the above

Question 50

Calculate the empirical formula of naphthalene if this compound is 93.71% carbon and 6.29% hydrogen by weight.

A) CH
B) CH₂
C) C₃H₂
D) C₄H₅
E) C₅H₄

Question 51

The molecular weight of naphthalene is 128.17 grams per mole. Use the results of the previous question to calculate the total number of atoms in a naphthalene molecule.

A) 9 atoms
B) 12 atoms
C) 18 atoms
D) 27 atoms
E) 38 atoms

Question 52

The term "carbohydrate" once meant a compound with the empirical formula CH₂O. What is the molecular formula of glucose (blood sugar) if the molecular weight of this carbohydrate is 180 g/mol?

A) CH₂O
B) C₄H₈O₄
C) C₆H₁₂O₆
D) C₁₂H₂₂O₁₁
E) none of the above

Question 53

A 1.854 g sample of D-ribose contains 0.01236 moles of this sugar which has an empirical formula of CH₂O. What is the ratio of the molecular formula to the empirical formula of this compound?

A) 1
B) 2
C) 3
D) 5
E) none of these

Question 54

The ribonucleic acids (RNA) that are so important in the biosynthesis of proteins all contain the sugar D-ribose, which contains three elements: C, H, and O. Elemental analysis suggests that D-ribose is 40.00% C and 6.71% H by weight. What is the empirical formula of this compound?

A) CHO
B) CH₂O
C) CH₃O
D) CH₃O₂
E) none of these

Question 55

Halothane is an anesthetic that is 12.17% C, 0.51% H, 40.48% Br, 17.96% Cl and 28.87% F by weight. Calculate the molecular formula of this compound if each molecule contains one hydrogen atom.

Question 56

A compound frequently used as a high-temperature lubricant has the formula MS₂, where M represents some metallic element. If this compound is 40.06% sulfur by mass, what is the identity of the metal M?

A) K
B) Fe
C) Cu
D) Mo
E) Pb

Question 57

In small quantities, the nicotine in tobacco is addictive. In large quantities, it is a deadly poison. Calculate the molecular formula of nicotine, C_xH_yN_z, if the molecular weight is 162.2 g/mol and 0.438 grams of this compound burn to form 1.188 grams of CO₂ and 0.341 grams of water.

Question 58

In 1763, the Reverend Edmund Stone suggested chewing the bark of the English willow (Salix abla) to treat a fever because it grows in moist regions where one was likely to catch a fever, and "... many natural maladies carry their cures along with them, or their remedies lie not far from their causes." It took 50 years to isolate the active ingredient in the bark, which was named salicylic acid. By the end of the 19^th century, salicylic acid was used to treat rheumatic fever, gout and arthritis. Many patients complained of chronic stomach irritation, however. Because his father was one of these patients, Felix Hoffman searched for a less acidic derivative of salicylic acid. In 1898, Hoffman reported that the acetyl ester of salicylic acid was both more effective and easier to tolerate than the parent compound. He named the compound aspirin, taking the prefix a- from the name of the acetyl group and spirin from the German name of the parent compound spirsure. Aspirin is 60.00% C, 4.48% H, and 35.5% O by weight. What is the total number of C, H and O atoms in the empirical formula of this compound?

A) less than 15 atoms
B) between 15 and 20 atoms
C) between 20 and 25 atoms
D) between 25 and 35 atoms
E) more than 35 atoms

Question 59

One of the concerns during the war against Iraq several years ago was fear of chemical warfare agents, such as the nerve agent VX. VX is the most dangerous material ever synthesized; a single drop of VX on the skin will kill an individual within hours. More than 2 million pounds of VX were made in Southern Indiana by 1968. They are still there, stored in 1600 canisters, packed three high. The canisters were welded together several years ago because of fear of exposure to VX if a tornado struck the storage facility. Elemental analysis of VX gives the following result: 49.41% C, 9.80% H, 5.24% N, 11.97% O, 11.58% P, and 11.99% S. How many carbon atoms does the empirical formula for this compound contain?
(Hint: Carry out the calculation to at least three significant figures.)

A) 3 or less atoms
B) 4 to 7 atoms
C) 8 to 11 atoms
D) 12 to 15 atoms
E) more than 15 atoms

Question 60

Assume that the empirical formula of VX (described in the previous question) is the same as the molecular formula. What is the molecular weight of VX?

A) less than 150 grams/mole
B) between 150 and 200 grams/mole
C) between 200 and 250 grams/mole
D) between 250 and 300 grams/mole
E) more than 300 grams/mole

Question 61

On March 20, 1995, terrorists released an organophosphate nerve gas known as "Sarin" at several points in the Tokyo subway system, killing 11 and injuring more than 5,500 people. Sarin was concealed in lunch boxes and soft-drink containers and placed on subway train floors. It was released as terrorists punctured the containers with umbrellas before leaving the trains. Elemental analysis of Sarin gives the following result: 34.29% C, 7.19% H, 22.84% O, 13.56% F, 22.11% P. How many carbon atoms does the empirical formula of this compound contain?

A) 2 or less atoms
B) 3 to 6 atoms
C) 7 to 10 atoms
D) 11 to 15 atoms
E) more than 15 atoms

Question 62

A sample of copper(II) sulfate, CuSO₄, that weighs 2.47 grams picks up
Water from the atmosphere to form a hydrate with the formula CuSO₄ • x H₂O. If the sample weighs 3.86 grams after it picks up water, what is the value of x?

A) 2
B) 2.5
C) 3
D) 4
E) 5

Question 63

The thermal decomposition of carbonates leads to the loss of CO₂. The decomposition of an unknown carbonate leads to a 35.1% weight loss. The unknown was which of the following compounds.

A) Li₂CO₃
B) MgCO₃
C) CaCO₃
D) ZnCO₃
E) BaCO₃

Question 64

In March of 2007 a number of pets were sickened or killed by pet food contaminated with the chemical melamine which is used in the manufacture of certain plastics. It is thought that the melamine was added to make a pet food additive appear to have more protein than it really did. Melamine is 28.57% C, 4.80% H, and 66.63% N by mass. What is melamine's empirical formula?

A) C₉H₅N₇
B) CHN₂
C) C₂HN₇
D) CH₂N₂
E) CHN

Question 65

In March of 2007 a number of pets were sickened or killed by pet food contaminated with the chemical melamine which is used in the manufacture of certain plastics. It is thought that the melamine was added to make a pet food additive appear to have more protein than it really did. Melamine has the empirical formula CH₂N₂. If the molecular weight of melamine is 126.15 g/mol, what is its molecular formula?

A) CH₂N₂
B) CH₃N₃
C) C₃H₆N₆
D) C₂H₄N₄
E) C₄H₈N₈

Question 66

If 0.50 moles of PbS are combined with 0.50 moles of O₂, how many moles of PbO can be produced by the following reaction?
2 PbS(s) + 3 O₂(g) $\rightarrow$ 2 PbO(s) + 2 SO₂(g)

A) 0.33
B) 0.50
C) 0.75
D) 2.0
E) none of these

Question 67

What would happen to the potential yield of sulfur dioxide in the previous question if the amount of oxygen was doubled?

A) It would decrease by a factor of 2.
B) It would decrease by a factor of 1.5.
C) It would remain constant.
D) It would increase by a factor of 1.5.
E) It would increase by a factor of 2.

Question 68

Acetylene gas, C₂H₂, burns in the presence of oxygen by the following reaction:
2 C₂H₂(g) + 5 O₂(g) $\rightarrow$ 2 H₂O(l) + 4 CO₂(g)
If 4.5 moles of acetylene gas are to be burned, how many moles of oxygen will be required for the complete reaction of the acetylene?

A) 4.5 moles
B) 23 moles
C) 8.1 moles
D) 5.0 moles
E) none of these

Question 69

For the reaction: 4 NH₃(g) + 5 O₂(g) $\rightarrow$ 4 NO(g) + 6 H₂O(l), how many moles of ammonia, NH₃, are required to react completely with 0.250 moles of oxygen?

A) 0.400
B) 0.500
C) 0.200
D) 0.313
E) 0.178

Question 70

The molecular formula of isooctane is C₈H₁₈. It burns in the presence of oxygen to form a mixture of CO₂ and H₂O. What is the ratio of moles of water to moles of carbon dioxide produced in this reaction?

A) 1:1
B) 2:1
C) 9:4
D) 9:8
E) none of the above

Question 71

A laboratory method for preparing oxygen (O₂) involves the decomposition of KClO₃.
KClO₃(s) $\rightarrow$ 2 KCI(s) + 3 O₂(g)
How many moles of oxygen are produced when 0.135 moles of KCl are produced by this reaction?

A) 0.135 mol
B) 0.090 mol
C) 0.203 mol
D) 0.405 mol
E) none of these

Question 72

What mass of O₂, in grams, is produced in the decomposition of 100 g of KClO₃ by the following reaction?
2 KClO₃(s) $\rightarrow$ 2 KCl(s) + 3 O₂(g)

A) 0.816 grams
B) 1.22 grams
C) 39.2 grams
D) 1.50 x 10² grams
E) 26.1 grams

Question 73

Iron ore is impure Fe₂O₃. When Fe₂O₃ is heated with an excess of carbon (coke), iron metal is produced. How many moles of Fe can be produced from 250 g of Fe₂O₃ by the following reaction?
Fe₂O₃ (s) + 3 C(s) $\rightarrow$ 2 Fe(l) + 3 CO(g)

A) 5.00 x 10² mol
B) 125 mol
C) 1.57 mol
D) 3.13 mol
E) 0.785 mol

Question 74

Calculate the number of moles of iron, Fe, produced when 0.500 moles of carbon monoxide, CO, react with an excess of iron oxide.
Fe₂O₃(s) + 3 CO(g) $\rightarrow$ 2 Fe(s) + 3 CO₂(g)

A) 2.00 moles
B) 1.00 moles
C) 0.750 moles
D) 0.166 moles
E) none of these

Question 75

Hydrogen chloride, HCI, can be made by the reaction of phosphorus trichloride, PCl₃, with water and then boiling the HCI gas out of the solution. Calculate the mass of HCI gas that can be prepared from 15.0 g of PCl₃ and an excess of water.
PCl₃(g) + 3 H₂O(l) $\rightarrow$ 3 HCI(aq) + H₃PO₃(aq)

A) 0.328 g
B) 3.97 g
C) 11.9 g
D) 35.7 g
E) 3.00 g

Question 76

Ethyl alcohol, C₂H₅OH, is also known as drinking alcohol. It can be produced by the fermentation of glucose by the following reaction.
C₆H₁₂O₆(aq) $\rightarrow$ 2 C₂H₅OH(aq) + 2 CO₂(g)
How many $\textbf{ moles }$ of ethanol can be produced from $\textbf{ 100 g }$ of glucose?

A) 100 moles
B) 200 moles
C) 0.556 moles
D) 1.11 moles
E) none of these

Question 77

Nitrogen reacts with red-hot magnesium to form magnesium nitride,
3 Mg(s) + N₂(g) $\rightarrow$ Mg₃N₂(s)
Which reacts with water to form magnesium hydroxide and ammonia,
Mg₃N₂(s) + 6 H₂O(l) $\rightarrow$ 3 Mg(OH)₂(aq) + 2 NH₃(aq)
How many grams of magnesium would you have to start with to prepare 15.0 grams of ammonia?

A) 13.3 g
B) 15.0 g
C) 20.0 g
D) 32.2 g
E) none of the above

Question 78

The chemical formula of ethanol is C₂H₆O. It burns in the presence of excess oxygen to form CO₂ and H₂O. How many grams of H₂O are produced from the combustion of 25.0 g of ethanol?

A) 9.78 g
B) 18.0 g
C) 25.0 g
D) 29.3 g
E) 54.1 g

Question 79

Sucrose, or "cane sugar," has the formula C₁₂H₂₂O₁₁. What weight of carbon dioxide can be produced from 10.0 grams of sucrose and 10.0 grams of oxygen?
C₁₂H₂₂O₁₁(s) + 12 O₂(g) $\rightarrow$ 12 CO₂(g) + 11 H₂O(g)

A) less than 5 grams
B) between 5 and 10 grams
C) between 10 and 15 grams
D) between 15 and 20 grams
E) more than 20 grams

Question 80

PF₃ reacts with XeF₄ to give PF₅. In theory, how many moles of PF₅ can be produced from 100.0 g of PF₃ and 50.0 g of XeF₄?
2 PF₃(g) + XeF₄(s) $\rightarrow$ 2 PF₅(g) + Xe(g)

A) 0.121 mol
B) 0.241 mol
C) 0.482 mol
D) 1.14 mol
E) 2.28 mol