Chemical Engineering Chapter 9 Which The Following Statements Correct Concerning

Introduction to Chemical Principles, 11e (Stoker)

Chapter 9 Chemical Calculations: The Mole Concept and Chemical Formulas

9.1 Multiple Choice

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

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 48.00 grams of carbon must contain ________.

A) 16.00 g of hydrogen

B) 12.00 g of hydrogen

C) 24.00 g of hydrogen

D) 8.00 g of hydrogen

3) What is the formula mass of Ba(C2H3O2)2?

A) 392.71 amu

B) 255.43 amu

C) 196.38 amu

D) 306.42 amu

4) Which of the following compounds has the largest formula mass?

A) BF3

B) NO2

C) HCN

D) CCl4

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

A) 121.12 amu

B) 149.12 amu

C) 110.12 amu

D) 243.03

amu

6) Glucose is the type of sugar the human body metabolizes to produce energy. Calculate the

molecular mass of glucose, C6H12O6.

A) 180.18 amu

B) 220.02 amu

C) 168.18 amu

D) 340.00 amu

7) What is the formula mass of crotonaldehyde, C4H6O?

A) 54.10 amu

B) 57.10 amu

C) 64.00 amu

D) 70.10 amu

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

A) 53.87%

B) 64.19%

C) 33.33%

D) 28.93%

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

10) In which of the following samples will the mass percentage of 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 of C2H6 have the same mass percentage of H.

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 C in cholesterol?

A) 84%

B) 76%

C) 91%

D) 56%

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

A) 18.51%

B) 40.46%

C) 29.74%

D) 46.39%

13) The mass percent of chlorine in Mg(ClO3)2 is:

A) 33.0%

B) 37.1%

C) 43.6%

D) 12.7%

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

A) 20.6%

B) 60.0%

C) 30.7%

D) 79.8%

15) Calculate the percentage composition of oxygen in K2CO3.

A) 34.73%

B) 11.65%

C) 13.39%

D) 39.82%

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 8.71% 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

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.

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

A) 2.40 x 1022 Cl atoms

B) 8.40 x 1024 Cl atoms

C) 3.90 x 1024 Cl atoms

D) 6.6 x 10−26 Cl atoms

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

A) The total number of hydrogen atoms present in one molecule of sugar is 22.

B) The total number of carbon atoms present in three moles of sugar is equal to 36 x (6.022 x

1023).

C) The mass of 0.600 moles of sugar is 205 grams.

D) All of the above statements are correct.

20) 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

21) A thimble of water contains 4.0 x 1021 molecules. The number of moles of H2O is:

A) 2.4 x 1045

B) 6.6 x 10-3

C) 6.6 x 10-43

D) 2.4 x 1023

22) 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) 1.72 x 1023

C) 1.81 x 1024

D) 2.11 x 10-24

23) Which of the following quantities does not contain the same number of atoms as 80.2 grams

of Ca?

A) 0.50 moles of P4 molecules

B) 64.2 grams of S

C) 6.02 1023 molecules of O2

D) 1 mole of Ni

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

A) 526 g

B) 702 g

C) 270 g

D) 486 g

25) 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

26) 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

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

A) 46.0

B) 6.02 x 1023

C) 1.96 x 1024

D) 5.1 x 10-25

28) 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

29) Which of the following statements is incorrect concerning BaF2?

A) The total number of fluorine ions present in one formula unit is 2 x (6.02 x 1023).

B) The total number of fluoride ions present in three moles of BaF2 is equal to 6 x(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.

30) Which of the following substances is paired with an incorrect molar mass?

A) S8 – 32.06 g

B) Na – 22.99 g

C) NO2 – 46.01 g

D) CO2 – 44.01 g

31) Avogadro’s number of aluminum atoms has a mass equal to ________.

A) 6.02 x 1023 g of aluminum

B) 14.01 g nitrogen

C) 26.98 g aluminum

D) 6.02 x 10−23 g of calcium

32) 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

33) Which of the following contains Avogadro’s number of molecules?

A) 8.8 g CO2

B) 34 g of NH3

C) 9.0 g of H2O

D) 98 g of H2SO4

34) 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 x1023 molecules.

D) It has a mass of 9.0 grams.

35) 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

36) 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

37) An atom of an element has a mass of 1.0555 x 10−22 grams. What is the atomic mass of the

element?

A) 63.542 amu

B) 196.90 amu

C) 179.20 amu

D) 195.11 amu

38) How many grams are present in 6.50 moles of Cu(NO3)2?

A) 124 g

B) 404 g

C) 1080 g

D) 1220 g

39) 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 g/mol

B) 35.20 g/mol

C) 99.00 g/mol

D) 101.0 g/mol

40) A beaker contains 0.964 grams of nitrogen. How many moles of molecular nitrogen does the

beaker contain?

A) 0.0688 mol

B) 2.26 x1023 mol

C) 0.0344 mol

D) 2.64 mol

41) Calculate the mass of 1.98 moles of Li2SO3.

A) 186 g

B) 155 g

C) 96.1 g

D) 316 g

42) Which element contains atoms with an average mass of 1.79 x 10−22 grams?

A) Fe

B) Sc

C) Ag

D) F

43) What is the mass, in grams, of an atom whose mass on the amu scale is 16.00 amu?

A) 2.658 x 10-23

B) 9.632 x 1024

C) 2.438 x 10-23

D) 3.012 x 10-23

44) 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

45) 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

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

A) 2.2 x 10-4 mol

B) 2.2 mol

C) 4.6 x 10-3 mol

D) 0.022 mol

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

A) 1.25 mol

B) 0.800 mol

C) 28.0 mol

D) 0.500 mol

48) 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

49) Which of the following is the correct “set-up” for the problem “How many atoms are present

in 15.0 g Na?”

A)

B)

C)

D)

50) The “set-up” for the problem “What is the mass, in grams, of 2.50 x 1022 atoms of Ca?” is as

follows. The except 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