Question 1

Of the substances shown in the figure, only N2O3 has an empirical formula that is the same as its molecular formula.

Accepted Answer

A) True 
 B)False

Question 2

If you have 10.0 g of sodium chloride, NaCl, how many formula units are in the sodium chloride sample?

Accepted Answer

A)  2.84 x 1025 
B)  3.52 x 1024 
C)  6.02 x 1024 
D)  1.03 x 1023 
E)  0.171F) D) and E)
G) A) and B)

Question 3

Calculate the molar mass of CuSO4.5H2O.

Accepted Answer

A)  159.62 g/mol
B)  249.70 g/mol
C)  177.64 g/mol
D)  185.72 g/mol
E)  446.48 g/molF) A) and E)
G) A) and D)

Question 4

Rank the substances in the figure from least atoms per mole to most atoms per mole. 3 2SO4 3 2SO4  C) Na 2SO4 3  D) NaCl 3 2SO4  E) H2SO4 3

Accepted Answer

A)  SO3 2SO4 
B)  Na 3 2SO4 
C)  Na 2SO4 3 
D)  NaCl 3 2SO4 
E)  H2SO4 3 < NaCl < NaF) A) and B)
G) B) and D)

Question 5

How many formula units are in a sample of rust, Fe2O3 that has a mass of 5.0 g?

Accepted Answer

A)  1.9 x 1025 
B)  0.031
C)  1.9 x 1022 
D)  0.070
E)  4.2 x 1022 F) B) and E)
G) B) and D)

Question 6

The following minerals contain zinc.Rank the minerals in order of percent zinc from least to greatest: sphalerite, ZnS; smithsonite, ZnCO3; zincite, ZnO; gahnite, ZnAl2O4.

Accepted Answer

A)  ZnO 2O4 3 
B)  ZnO 3 2O4 
C)  ZnAl2O4 3 
D)  ZnAl2O4 3 
E)  ZnCO3 2O4 < ZnS < ZnOF) A) and C)
G) A) and B)

Question 7

In order to prepare a 0.0500 M NaOH solution, to what volume would you dilute 25.0 mL of 2.50 M NaOH?

Accepted Answer

A)  1.25 x 103 L
B)  1.25 L
C)  1.25 mL
D)  0.0625 L
E)  0.500 LF) None of the above
G) A) and D)

Question 8

Barium sulfate is a compound used to assist in diagnosing medical problems through x-ray analysis and is 58.8% barium.What mass of barium is present in a 620 mg tablet of barium sulfate?

Accepted Answer

A)  81 mg
B)  230 mg
C)  360 mg
D)  1100 mg
E)  11 mgF) A) and C)
G) All of the above

Question 9

4.Malachite is a green colored mineral that is 57.5% copper.What mass of copper is present in a 250.0 g sample of malachite?

Accepted Answer

A)  63.6 g
B)  127 g
C)  435 g
D)  36.5 g
E)  144 gF) B) and D)
G) B) and C)

Question 10

To obtain 0.50 moles of potassium nitrate from a solution, you could either use 100.0 mL of a 5.0 M solution, or 250.0 mL of a 2.0 M solution.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following statements is incorrect?

Accepted Answer

A)  CH4 has ¼ as many carbon atoms as hydrogen atoms.
B)  H2O has twice as many oxygen atoms as hydrogen atoms.
C)  SO3 has three times as many oxygen atoms as sulfur atoms.
D)  P4O10 has 2.5 times as many oxygen atoms as phosphorus atoms.
E)  SrF2 has twice as many fluoride ions as strontium ions.F) B) and D)
G) A) and E)

Question 12

If the molar mass of a substance is 20.0 g/mol, what is the mass of 3.01 x 1025 molecules of the substance?

Accepted Answer

A)  0.400 g
B)  10.0 g
C)  1.00 x 103 g
D)  6.02 x 1026 g
E)  1.20 x 1025 gF) C) and D)
G) A) and B)

Question 13

Calculate the volume of 12.0 M HCl that would be required to obtain 3.00 moles of the solute.

Accepted Answer

A)  2.50 x 102 L
B)  2.50 x 102 mL
C)  36.0 mL
D)  36.0 L
E)  9.11 LF) C) and E)
G) A) and E)

Question 14

Butyric acid has a very unpleasant odor.It is present in some rotting foods, body odor and vomit.Butyric acid has a molar mass of 88.10 g/mol and consists of 54.53% C, 9.153% H, and 36.32% O.What is the molecular formula of butyric acid?

Accepted Answer

A)  CH2O0.5 
B)  CH2O
C)  CH4O
D)  C2H4O
E)  C4H8O2 F) A) and B)
G) A) and C)

Question 15

Given the following molecular formulas, determine the empirical formula of each compound: Cl2O5, PbCl4, N2O4, C3H6Cl2.

Accepted Answer

A)  ClO2.5, PbCl4, NO2, C3H6Cl2 
B)  Cl2O5, PbCl4, NO2, C3H6Cl2 
C)  Cl2O5, PbCl4, NO2, CH2Cl
D)  Cl2O5, PbCl4, N2O4, C3H6Cl2 
E)  Cl2O5, PbCl, N2O4, C3H6Cl2 F) A) and C)
G) A) and B)

Question 16

Calculate the number of moles of CaCO3 (calcium carbonate, or limestone)  in a 20.0 g sample of this substance.

Accepted Answer

A)  2.00 x 103 moles
B)  0.200 mole
C)  0.294 mole
D)  1.36 x 103 moles
E)  1.20 x 103 molesF) A) and D)
G) A) and C)

Question 17

A chemical reaction requires 3.50 moles of copper(II)  nitrate, Cu(NO3) 2.What mass of copper(II)  nitrate is needed?

Accepted Answer

A)  327 g
B)  93.6 g
C)  188 g
D)  656 g
E)  53.6 gF) B) and C)
G) A) and E)

Question 18

The solute in the solution shown in the figure is CaCl.

Accepted Answer

A) True 
 B)False

Question 19

Molarity is defined as the moles of solute divided by the liters of solvent.

Accepted Answer

A) True 
 B)False

Question 20

Given the following molecular formulas, determine the empirical formula of each compound: N2O5, PCl3, H2O2, C6H4Cl2.

Accepted Answer

A)  N2O5, PCl3, HO, C6H4Cl2 
B)  N2O5, PCl3, H2O, C6H4Cl2 
C)  N2O5, PCl3, H2O2, C3H2Cl2 
D)  NO2.5, PCl3, HO, C3H2Cl
E)  N2O5, PCl3, HO, C3H2ClF) B) and D)
G) A) and C)

Exam 4: Chemical Composition

Calculate the volume of 12.0 M HCl that would be required to obtain 3.00 moles of the solute.

Correct AnswerverifiedShow Answer

How many formula units are in a sample of rust, Fe2O3 that has a mass of 5.0 g?

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Butyric acid has a very unpleasant odor.It is present in some rotting foods, body odor and vomit.Butyric acid has a molar mass of 88.10 g/mol and consists of 54.53% C, 9.153% H, and 36.32% O.What is the molecular formula of butyric acid?

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Calculate the number of moles of CaCO3 (calcium carbonate, or limestone) in a 20.0 g sample of this substance.

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Molarity is defined as the moles of solute divided by the liters of solvent.

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Barium sulfate is a compound used to assist in diagnosing medical problems through x-ray analysis and is 58.8% barium.What mass of barium is present in a 620 mg tablet of barium sulfate?

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4.Malachite is a green colored mineral that is 57.5% copper.What mass of copper is present in a 250.0 g sample of malachite?

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A chemical reaction requires 3.50 moles of copper(II) nitrate, Cu(NO3) 2.What mass of copper(II) nitrate is needed?

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Which of the following statements is incorrect?

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To obtain 0.50 moles of potassium nitrate from a solution, you could either use 100.0 mL of a 5.0 M solution, or 250.0 mL of a 2.0 M solution.

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Given the following molecular formulas, determine the empirical formula of each compound: N2O5, PCl3, H2O2, C6H4Cl2.

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Given the following molecular formulas, determine the empirical formula of each compound: Cl2O5, PbCl4, N2O4, C3H6Cl2.

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Rank the substances in the figure from least atoms per mole to most atoms per mole.

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The following minerals contain zinc.Rank the minerals in order of percent zinc from least to greatest: sphalerite, ZnS; smithsonite, ZnCO3; zincite, ZnO; gahnite, ZnAl2O4.

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If you have 10.0 g of sodium chloride, NaCl, how many formula units are in the sodium chloride sample?

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Of the substances shown in the figure, only N2O3 has an empirical formula that is the same as its molecular formula.

Correct AnswerverifiedShow Answer

If the molar mass of a substance is 20.0 g/mol, what is the mass of 3.01 x 1025 molecules of the substance?

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Calculate the molar mass of CuSO4.5H2O.

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The solute in the solution shown in the figure is CaCl.

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In order to prepare a 0.0500 M NaOH solution, to what volume would you dilute 25.0 mL of 2.50 M NaOH?

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How many formula units are in a sample of rust, Fe₂O₃ that has a mass of 5.0 g?

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Calculate the number of moles of CaCO₃ (calcium carbonate, or limestone) in a 20.0 g sample of this substance.

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A chemical reaction requires 3.50 moles of copper(II) nitrate, Cu(NO₃) ₂.What mass of copper(II) nitrate is needed?

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Given the following molecular formulas, determine the empirical formula of each compound: N₂O₅, PCl₃, H₂O₂, C₆H₄Cl₂.

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Given the following molecular formulas, determine the empirical formula of each compound: Cl₂O₅, PbCl₄, N₂O₄, C₃H₆Cl₂.

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The following minerals contain zinc.Rank the minerals in order of percent zinc from least to greatest: sphalerite, ZnS; smithsonite, ZnCO₃; zincite, ZnO; gahnite, ZnAl₂O₄.

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Of the substances shown in the figure, only N₂O₃ has an empirical formula that is the same as its molecular formula.

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If the molar mass of a substance is 20.0 g/mol, what is the mass of 3.01 x 10²⁵ molecules of the substance?

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Calculate the molar mass of CuSO₄.5H₂O.

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