Deck 9: Chemical Calculations: the Mole Concept and Chemical Formulas

Question 1

Which of the following information items would be most useful in verifying the law of definite proportions?

A) analysis information about two compounds that contain the same elements in different proportions
B) a number of samples of a pure compound collected from various locations
C) the total mass of the reactants in a series of reactions
D) the total mass of the products in a series of reactions

Answer 1

a number of samples of a pure compound collected from various locations

Question 2

According to the law of definite proportions, if a sample of a compound contains 24.00 grams of carbon and 4.00 grams of hydrogen, then another sample of the same compound which contains 48.0 grams of carbon must contain ________.

A) 16.0 g of hydrogen
B) 12.0 g of hydrogen
C) 24.0 g of hydrogen
D) 8.00 g of hydrogen

Answer 2

8.00 g of hydrogen

Question 3

What is the formula weight of Ba(C₂H₃O₂)₂ in grams per mole?

A) 392.71
B) 255.43
C) 196.38
D) 306.42

Answer 3

255.43

Question 4

Which of the following compounds has the largest formula mass?

A) BF₃
B) NO₂
C) HCN
D) CCl₄

Question 5

The formula mass of (NH₄)₃PO₄, is ________.

A) 121.12 amu
B) 149.12 amu
C) 110.12 amu
D) 159.68 amu

Question 6

Glucose is the type of sugar the human body metabolizes to produce energy. Calculate the formula mass of glucose, C₆H₁₂O₆.

A) 180.18 amu
B) 220.02 amu
C) 168.18 amu
D) 340.00 amu

Question 7

What is the molar mass of crotonaldehyde (C₄H₆O)?

A) 54.1 g/mol
B) 70.1 g/mol
C) 64.0 g/mol
D) 70.0 g/mol

Question 8

The mass percentage of Cl in the compound KClO₃ is ________.

A) 53.87%
B) 64.19%
C) 33.33%
D) 28.93%

Question 9

In which of the following compounds is the mass percentage of calcium the greatest?

A) Ca(C₂H₃O₂)₂
B) CaCl₂
C) CaH₂
D) Ca(NO₃)₂

Question 10

In which of the following samples will the mass percentage H be the greatest?

A) 3.25 g of C₂H₆
B) 15.0 g of C₂H₆
C) 36.0 g of C₂H₆
D) All samples have the same mass percentage H.

Question 11

A 2.00 g sample of cholesterol contains 1.68 g C, 0.24 g H, and 0.080 g O. What is the percent composition of oxygen in cholesterol?

A) 4.0%
B) 76%
C) 91%
D) 56%

Question 12

Calculate the percentage composition of oxygen in Ca(C₂H₃O₂)₂.

A) 40.47%
B) 40.46%
C) 29.74%
D) 46.39%

Question 13

The mass percent of chlorine in Mg(ClO₃)₂ is ________.

A) 33.0%
B) 37.1%
C) 43.6%
D) 12.7%

Question 14

What is the mass percent of carbon in dimethyl sulfoxide, C₂H₆SO?

A) 20.6%
B) 60.0%
C) 30.7%
D) 79.8%

Question 15

Calculate the percentage composition of oxygen in K₂CO₃.

A) 34.73%
B) 11.65%
C) 13.39%
D) 39.82%

Question 16

Nicotine (C₁₀H₁₄N₂) is a byproduct of the tobacco industry and is used as an agricultural insecticide. Calculate the percent composition of each element in nicotine.

A) 74.0 % C   8.70 % H   17.3 % N
B) 83.7 % C   4.45 % H   11.9 % N
C) 70.2 % C   10.5 % H   10.3 % N
D) 90.0 % C   1.50 % H   8.50 % N

Question 17

Which of the following statements concerning the numerical value 6.02 x 10²³ is incorrect?

A) It is called Avogadro's number.
B) It is the number of carbon atoms in one mole of CO₂ molecules.
C) It is the mass, in grams, of one mole of any substance.
D) It is the number of atoms in one mole of He atoms.

Question 18

Which of the following quantities does not contain the same number of atoms as there are in 80.2 grams of Ca?

A) 0.50 moles of P₄ molecules
B) 64.2 grams of S
C) 6.02 x 10²³ molecules of O₂
D) 6.02 x 10²³ atoms of Ni

Question 19

How many Cl atoms are present in 2.16 moles of NCl₃?

A) 2.4 x 10²² Cl atoms
B) 8.4 x 10²⁴ Cl atoms
C) 3.90 x 10²⁴ Cl atoms
D) 6.6 x 10^-26 Cl atoms

Question 20

Calculate the mass (grams) of 0.750 moles of Al₂(Cr₂O₇)₃.

A) 526 g
B) 702.0 g
C) 270.0 g
D) 486.0 g

Question 21

Calculate the number of iron atoms in 6.98 x 10^-3 grams of iron.

A) 9.37 x 10²⁸ atoms
B) 3.92 x 10¹⁹ atoms
C) 3.24 x 10²³ atoms
D) 7.53 x 10¹⁹ atoms

Question 22

Which of the following statements is correct concerning common table sugar, C₁₂H₂₂O₁₁?

A) The total number of hydrogen atoms present in one molecule is 22.
B) The total number of carbon atoms present in three moles of sugar is equal to 36 (6.022 x 10²³).
C) The mass of 0.600 moles of sugar is 205 grams.
D) All of the above statements are correct.

Question 23

Calculate the number of lithium atoms in 3.66 moles of lithium.

A) 2.20 x 10²⁴
B) 8.97 x 10²⁶
C) 3.54 x 10²⁵
D) 6.23 x 10²⁵

Question 24

Acetic acid (C₂H₄O₂) is the principle component of vinegar. 96.0 g of C₂H₄O₂ is equivalent to ________ moles of C₂H₄O₂ and contains ________ hydrogen (H) atoms.

A) 1.60; 9.64 x 10²³
B) 0.626; 3.85 x 10²⁴
C) 0.943; 7.29 x 10²⁴
D) 1.60; 3.85 x 10²⁴

Question 25

You have been given 3.50 moles of ammonia, NH₃. How many molecules of ammonia does it contain?

A) 4.75 x 10^-25
B) 2.11 x 10²⁴
C) 1.81 x 10²⁴
D) 2.21 x 10^-24

Question 26

How many molecules of ethanol, C₂H₅OH, are contained in 150. gram sample?

A) 46.0
B) 6.02 x 10²³
C) 1.96 x 10²⁴
D) 5.1 x 10^-25

Question 27

Sugar has an empirical formula of CH₂O and a molar mass of 180.2 g/mol. If one teaspoon of sugar weighs 3.50 grams, how many moles and molecules of sugar are present?

A) 0.117 moles, 7.03 x 10²² molecules
B) 0.0194 moles, 3.24 x 10²⁶ molecules
C) 0.0194 moles, 1.17 x 10²² molecules
D) 0.0583 moles, 3.51 x 10²² molecules

Question 28

Which of the following statements is incorrect concerning BaF₂?

A) The total number of fluorine ions present in one formula unit is 2 (6.02 x 10²³).
B) The total number of fluoride ions present in three moles of BaF₂ is equal to 6 (6.02 x 10²³).
C) The mass of 0.600 moles of BaF₂ is 105 grams.
D) 0.600 moles of BaF₂ is equivalent to 3.61 x 10²³ formula units of BaF₂.

Question 29

Avogadro's number of aluminum atoms has a mass equal to ________.

A) 6.02 x 10²³ g of aluminum
B) 14.01 g of nitrogen
C) 26.98 g of aluminum
D) 6.02 x 10^-23 g of calcium

Question 30

Which of these samples contains the largest number of particles?

A) 0.20 g of H₂ molecules
B) 0.10 mol of N₂ molecules
C) 1.90 g of F atoms
D) 0.20 mol of He atoms

Question 31

Which of the following statements about "one-half mole of H₂O" is incorrect?

A) It contains the same number of molecules as one-half mole of CCl₄.
B) It has the same mass, in grams, as one-half mole of CCl₄.
C) It contains 3.01 x 10²³ molecules.
D) It has a mass of 9.0 grams.

Question 32

Which of the following contains the greatest number of atoms?

A) 0.25 mole SO₂
B) 0.75 moles He
C) 0.50 moles Cl₂O
D) 0.70 moles NH₃

Question 33

The number of atoms contained in 16.0 grams of Mg would be the same as the number of molecules contained in ________ grams of N₂O.

A) 57.6
B) 29.0
C) 38.0
D) 66.2

Question 34

An atom of an element has a mass of 1.0555 x 10^-22 grams. What is the atomic mass of the element?

A) 63.541 amu
B) 196.90 amu
C) 179.20 amu
D) 195.11 amu

Question 35

How many grams are present in 6.5 moles of Cu(NO₃)₂?

A) 124 g
B) 404 g
C) 1080 g
D) 1200 g

Question 36

Which element contains atoms with an average mass of 1.79 x 10^-22 grams?

A) Fe
B) Sc
C) Ag
D) F

Question 37

What is the molar mass of a substance if 0.5602 moles of the substance has a mass of 19.72 grams?

A) 24.30
B) 35.20
C) 99.00
D) 101.0

Question 38

A beaker contains 0.964 grams of nitrogen. How many moles of molecular nitrogen does the beaker contain?

A) 0.0688 mol
B) 2.262 x 10²³ mol
C) 0.0344 mol
D) 2.64 mol

Question 39

Calculate the mass of 1.98 moles of Li₂SO₃.

A) 186
B) 155.37
C) 96.13
D) 316.40

Question 40

One mole of OF₂ molecules contains ________.

A) 16.0 atoms of O
B) 38.0 atoms of F
C) 2 moles of F atoms
D) one O atom

Question 41

2.00 formula units of the compound K₂S contains ________.

A) 4 K atoms
B) 2.00 moles of S atoms
C) 2.00 grams of K₂S
D) 39.09 g of K

Question 42

Calculate the number of moles of aspirin, C₉H₈O₄, in a 4.0 gram tablet.

A) 2.2 x 10^-4
B) 2.2
C) 4.6 x 10^-3
D) 0.022

Question 43

How many moles of nitrogen, N₂, are contained in a 35.0 g sample?

A) 1.25 moles
B) 0.80 moles
C) 28.0 mol
D) 0.50 mol

Question 44

How many grams of carbon are present in 26.2 grams of H₂CO₃?

A) 11.60 g
B) 16.8 g
C) 47.3 g
D) 5.07 g

Question 45

Which of the following is the correct "set-up" for the problem "How many atoms are present in 15.0 g Na?"

A) 15.0 g Na ×
B) 15.0 g Na × ×
C) 15.0 g Na × ×
D) 15.0 g Na ×

Question 46

The "set-up" for the problem "What is the mass, in grams, of 2.50 × 10²² atoms of Ca?" below is correct, except numbers in the last conversion factor have been replaced by the letters A and B. What are the numerical values of A and B, respectively?

A) 1 mole and 6.02 x 10²³ atoms
B) 40.08 g and 1 mol
C) 6.02 x 10²³ g and 1 atom
D) 40.08 mol and 6.02 x 10²³ atoms

Question 47

Which of the following is the correct "set-up" for the problem "How many moles of C are present in 25.00 grams of C₆H₁₂O₆?"

A)
B)
C)
D)

Question 48

The "set-up" for the problem "How many oxygen atoms are there in 4.0 moles of N₂O₄?" below is correct, except for the use of letters rather than numbers in the conversion factors. What are the correct numerical values of A and D, respectively?

A) 4 and 4
B) 1 and 4
C) 4 and 1
D) 4 and 6.02 10²³

Question 49

Which of the following is the correct "set-up" for the problem "How many grams of S are present in 50.0 g of S₄N₄?"

A)
B)
C)
D)

Question 50

The number of moles of O atoms in 27 g of OF₂ is ________.

A) 13 moles
B) 6.4 moles
C) 0.50 moles
D) 0.20 moles

Question 51

How many atoms of H are present in 27.6 g of NH₃?

A) 2.93 x 10²⁴
B) 3.67 x 10²³
C) 9.79 x 10²⁴
D) 3.55 x 10²⁶

Question 52

How many atoms are present in 0.65 moles of P₄O₁₀?

A) 8.71 x 10²⁴ atoms
B) 2.49 x 10²⁴ atoms
C) 2.49 x 10²⁵ atoms
D) 5.5 x 10²⁴ atoms

Question 53

Calculate the number of potassium ions present in a 16.42 gram sample of K₃P.

A) 2.931 x 10²⁴ potassium ions
B) 2.004 x 10²³ potassium ions
C) 1.466 x 10²⁴ potassium ions
D) 2.474 x 10²³ potassium ions

Question 54

How many carbon atoms are there in 25.0 grams of Al₂(CO₃)₃?

A) 5.96 x 10²⁴ atoms
B) 4.23 x 10²² atoms
C) 7.08 x 10²⁵ atoms
D) 1.93 x 10²³ atoms

Question 55

Which of the following is the empirical formula for the compound C₂H₄O₂?

A) C₃H₆O₃
B) CH₂O
C) CHO
D) C₂HO

Question 56

The empirical formula of C₁₀H₂₀ is ________.

A) C₁₀H₂₀
B) C₅H₁₀
C) C₂H₄
D) CH₂

Question 57

The empirical formula of a compound is CH₂O and its formula weight is 120.12 amu. What is the molecular formula?

A) C₂H₄O₂
B) C₃H₆O₃
C) C₄H₈O₄
D) C₅H₁₀O₅

Question 58

What is the empirical formula of a compound that contains 78.11% B and 21.89% H?

A) BH₂
B) BH₃
C) B₂H₆
D) B₂H₃

Question 59

What is the molecular formula of a compound that contains 40.0% C, 6.71 % H, and 53.29% O? The molecular mass of this compound is 60.05.

A) C₂H₄O₂
B) CH₂O
C) C₂H₃O₄
D) C₂H₂O₄

Question 60

Analysis of a sample of a compound shows that 0.130 mole of Cl, 0.130 mole of H and 0.520 mole of O are present. What is the empirical formula of the compound?

A) HClO
B) HClO₂
C) HClO₃
D) HClO₄

Question 61

If a 1.59 gram sample of a carbon-containing compound is burned in air, 1.01 gram of CO₂ is produced. What is the percent carbon in the compound?

A) 29%
B) 17%
C) 55%
D) 92%

Question 62

Analysis of an unknown nickel oxide compound indicated that the molar ratio of nickel to oxygen was 0.167 to 0.251, respectively. What is the empirical formula for the compound?

A) Ni₃O₄
B) NiO
C) NiO₃
D) Ni₂O₃

Question 63

A sample of an ionic compound was analyzed and found to contain 6.072 g of sodium, 8.474 g of sulfur, and 6.336 g of oxygen. What is its empirical formula?

A) NaSO₃
B) Na₂SO₃
C) Na₂S₂O₃
D) Na₂SO₄

Question 64

Analysis of an unknown sample indicated the sample contained 0.140 grams of N and 0.320 grams of O. The molar mass of the compound was determined to be 92.02 amu. What is the molecular formula of the compound?

A) NO
B) N₂O
C) N₂O₄
D) NO₂

Question 65

Carbohydrates have an empirical formula of CH₂O. What is the molecular formula of the sugar maltose if it has a molar mass of 180.18?

A) C₃H₆O₃
B) C₄H₈O₄
C) C₅H₁₀O₅
D) C₆H₁₂O₆

Question 66

Octane is a principle component of gasoline. The empirical formula of octane is C₄H₉, and the molar mass of octane is 114.26 grams per mole. What is the molecular formula of octane?

A) C₄H₉
B) C₁₂H₃₆
C) C₁₂H₂₇
D) C₈H₁₈

Question 67

The empirical formula of a compound was determined to be P₂O₃. The molecular weight of the compound is 220 g/mol. What is the molecular formula of the compound?

A) P₂O₃
B) P₄O₆
C) P₂O₅
D) P₄O₁₀

Question 68

Determine the percentage composition for the compound C₁₀H₁₄N₂.

Question 69

Match the statements on the left with an appropriate response from the right. Responses on the right may be used more than once or need not be used at all.

-________ has a mass of 4.0 grams

A) 1/4 mole CH₄
B) 1/4 mole NH₃
C) 2 moles H₂O
D) 1/2 mole N₂H

Question 70

Match the statements on the left with an appropriate response from the right. Responses on the right may be used more than once or need not be used at all.

-________ contains 1.20 x 10²⁴ molecules

A) 1/4 mole CH₄
B) 1/4 mole NH₃
C) 2 moles H₂O
D) 1/2 mole N₂H

Question 71

Match the statements on the left with an appropriate response from the right. Responses on the right may be used more than once or need not be used at all.

-________ contains 1 mole of atoms

A) 1/4 mole CH₄
B) 1/4 mole NH₃
C) 2 moles H₂O
D) 1/2 mole N₂H

Question 72

Match the statements on the left with an appropriate response from the right. Responses on the right may be used more than once or need not be used at all.

-________ contains 4 moles of H atoms

A) 1/4 mole CH₄
B) 1/4 mole NH₃
C) 2 moles H₂O
D) 1/2 mole N₂H

Question 73

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) formula mass of CBr₄(II) formula mass of P₂S₃

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 74

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) grams in 1 mole of SiF₄(II) grams in 1 mole of AsF₃

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 75

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) moles in 50 grams of N₂(II) moles in 50 grams of H₂S

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 76

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) molecules in 3 moles of SO₂(II) molecules in 3 moles of SO₃

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 77

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) atoms in 2 moles of NO₂(II) atoms in 2 moles of N₂O

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 78

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) molecules in 28 grams of Cl₂(II) molecules in 28 grams of NaCl

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 79

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) moles of N atoms in 34 g NH₃(II) moles of N atoms in 28 g of N₂

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.

Question 80

Contrast the two members of each pair in the statements on the left, and then select your response from the response list on the right.

-________(I) moles of O atoms in Avogadro's number of SO₂ molecules(II) moles of O atoms in twice Avogadro's number of CO molecule

A) I is greater than II.
B) I is less than II.
C) I is equal to II.
D) It is impossible to make a comparison between I and II.