Question 1

If the molar mass of a substance is 20.0 g/mol, what is the mass of 4.01 × 1023 molecules of the substance?

Accepted Answer

A)  30.0 g
B)  13.3 g
C)  8.02 × 1024 g
D)  1.20 × 1025 g
E)  3.00 gF) A) and B)
G) A) and C)

Question 2

A large salt crystal is found to have a mass of 0.128 g. How many formula units of sodium chloride, NaCl, are in the salt crystal? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Accepted Answer

To determine the number of formula units...

Question 3

Calculate the molarity of a solution prepared by dissolving 18.5 g of KOH in enough water to make 1.50 L of solution.

Accepted Answer

To calculate the molarity of the solutio...

Question 4

Which of the following statements regarding empirical formulas, molecular formulas, and percent composition is correct?

Accepted Answer

A)  The empirical formula and molecular formula of a given compound are always the same.
B)  Two compounds having different percent compositions of the same two elements are not the same compound.
C)  The empirical formula and molecular formula of a given compound are never the same.
D)  Data on the percent composition of the elements in a given compound is insufficient to determine the empirical formula of the compound.
E)  The compound S2Cl2 would have the same empirical and molecular formulas.F) B) and D)
G) All of the above

Question 5

Which of the substances in the figure have the same empirical and molecular formulas? 2Cl2 and C6H6 B) none of the substances C) all of the substances D) N2O3 and NaCl E) N2O3 only" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  S2Cl2 and C6H6
B)  none of the substances
C)  all of the substances
D)  N2O3 and NaCl
E)  N2O3 onlyF) B) and E)
G) All of the above

Question 6

Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Li, He, Mg, C

Accepted Answer

A)  He 
B)  C 
C)  Li 
D)  He 
E)  Mg < C < Li < HeF) A) and B)
G) B) and C)

Question 7

How many formula units are in 0.25 mole of Na2O?

Accepted Answer

A)  4.5 × 1023
B)  0.75
C)  1.5 × 1023
D)  4.2 × 10−25
E)  0.25F) A) and B)
G) C) and D)

Question 8

How many sodium ions are in 125 g of Na2SO4?

Accepted Answer

A)  1.06 × 024 atoms
B)  5.30 × 1023 atoms
C)  6.84 × 1023 atoms
D)  1.37 × 1024 atoms
E)  1.46 × 10-24 atomsF) A) and D)
G) B) and D)

Question 9

How many atoms of iron are in 26.5 g of Fe2O3? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Accepted Answer

To determine the number of iron atoms in...

Question 10

How many oxygen atoms are in 0.25 mole of SO3? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Accepted Answer

The chemical formula provided, "SO," doe...

Question 11

Acetaminophen is the active ingredient in Tylenol. It consists of 63.56% C, 6.00% H, 9.27% N, and 21.17% O. What is the empirical formula of acetaminophen?

Accepted Answer

A)  C8H8NO2
B)  C8H9NO2
C)  C6HNO2
D)  C5.3H5.9N0.7O1.3
E)  C4H4NOF) None of the above
G) A) and C)

Question 12

Calculate the moles of sucrose, C12H22O11, in a 15.0-g sample of this substance.

Accepted Answer

A)  342 mol
B)  22.8 mol
C)  5.13 × 103 mol
D)  4.38 × 10-2 mol
E)  0.517 molF) A) and D)
G) B) and D)

Question 13

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

Question 14

If you wished to prepare 1.50 liter of 0.30 M HCl solution from a stock solution that has a concentration of 6.0 M, what volume of the 6.0 M solution would be required?

Accepted Answer

To prepare a diluted solution from a con...

Question 15

What is the mass of 1.2 × 1024 molecules of F2?

Accepted Answer

A)  0.052 g
B)  9.5 g
C)  19 g
D)  38 g
E)  76 gF) B) and D)
G) C) and E)

Question 16

5.06 moles of iron(II) phosphate, Fe3(PO4) 2, are produced in a reaction. What mass of iron(II) phosphate is produced?

Accepted Answer

A)  5.20 × 102 g
B)  20.3 g
C)  1.81 × 103 g
D)  3.05 × 1024 g
E)  70.7 gF) A) and D)
G) C) and D)

Question 17

What is the mass of 7.4 × 1024 molecules of SO3?

Accepted Answer

A)  12 g
B)  590 g
C)  980 g
D)  6.5 g
E)  0.15 gF) A) and B)
G) C) and E)

Question 18

Image B in the figure shows a more concentrated solution because there are more water molecules.

Accepted Answer

A) True 
 B)False

Question 19

How many moles are in a sample of ethanol, CH3CH2OH that has a volume of 100.0 mL? The molar mass and density of ethanol are 46.07 g/mol and 0.789 g/mL, respectively.

Accepted Answer

A)  78.9 mol
B)  1.71 mol
C)  36.3 mol
D)  2.75 mol
E)  0.504 molF) A) and E)
G) A) and D)

Question 20

What mass of NaCl is present in 125.0 mL of a 0.100 M NaCl solution?

Accepted Answer

A)  125 g
B)  12.5 g
C)  73.0 g
D)  0.730 g
E)  46.8 gF) A) and B)
G) B) and E)

Exam 4: Chemical Composition

What mass of NaCl is present in 125.0 mL of a 0.100 M NaCl solution?

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How many formula units are in 0.25 mole of Na2O?

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How many sodium ions are in 125 g of Na2SO4?

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Calculate the moles of sucrose, C12H22O11, in a 15.0-g sample of this substance.

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What is the mass of 7.4 × 1024 molecules of SO3?

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Which of the following statements regarding empirical formulas, molecular formulas, and percent composition is correct?

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Acetaminophen is the active ingredient in Tylenol. It consists of 63.56% C, 6.00% H, 9.27% N, and 21.17% O. What is the empirical formula of acetaminophen?

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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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How many oxygen atoms are in 0.25 mole of SO3? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Correct AnswerAnswered by ExamLex AIThe chemical formula provided, "SO," doe...View AnswerShow Answer

5.06 moles of iron(II) phosphate, Fe3(PO4) 2, are produced in a reaction. What mass of iron(II) phosphate is produced?

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A large salt crystal is found to have a mass of 0.128 g. How many formula units of sodium chloride, NaCl, are in the salt crystal? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Correct AnswerAnswered by ExamLex AITo determine the number of formula units...View AnswerShow Answer

Which of the substances in the figure have the same empirical and molecular formulas?

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What is the mass of 1.2 × 1024 molecules of F2?

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How many moles are in a sample of ethanol, CH3CH2OH that has a volume of 100.0 mL? The molar mass and density of ethanol are 46.07 g/mol and 0.789 g/mL, respectively.

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Rank the following elements in order from least to most number of moles of atoms in a 10.0 g sample: Li, He, Mg, C

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If you wished to prepare 1.50 liter of 0.30 M HCl solution from a stock solution that has a concentration of 6.0 M, what volume of the 6.0 M solution would be required?

Correct AnswerAnswered by ExamLex AITo prepare a diluted solution from a con...View AnswerShow Answer

Calculate the molarity of a solution prepared by dissolving 18.5 g of KOH in enough water to make 1.50 L of solution.

Correct AnswerAnswered by ExamLex AITo calculate the molarity of the solutio...View AnswerShow Answer

If the molar mass of a substance is 20.0 g/mol, what is the mass of 4.01 × 1023 molecules of the substance?

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How many atoms of iron are in 26.5 g of Fe2O3? Express your answer as a multiple or a fraction of Avogadro's number, NA.

Correct AnswerAnswered by ExamLex AITo determine the number of iron atoms in...View AnswerShow Answer

Image B in the figure shows a more concentrated solution because there are more water molecules.

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How many formula units are in 0.25 mole of Na₂O?

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How many sodium ions are in 125 g of Na₂SO₄?

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Calculate the moles of sucrose, C₁₂H₂₂O₁₁, in a 15.0-g sample of this substance.

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What is the mass of 7.4 × 10²⁴ molecules of SO₃?

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How many oxygen atoms are in 0.25 mole of SO₃? Express your answer as a multiple or a fraction of Avogadro's number, N_A.

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The chemical formula provided, "SO," doe...
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5.06 moles of iron(II) phosphate, Fe₃(PO₄) ₂, are produced in a reaction. What mass of iron(II) phosphate is produced?

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A large salt crystal is found to have a mass of 0.128 g. How many formula units of sodium chloride, NaCl, are in the salt crystal? Express your answer as a multiple or a fraction of Avogadro's number, N_A.

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Answered by ExamLex AI
To determine the number of formula units...
View Answer

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What is the mass of 1.2 × 10²⁴ molecules of F₂?

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How many moles are in a sample of ethanol, CH₃CH₂OH that has a volume of 100.0 mL? The molar mass and density of ethanol are 46.07 g/mol and 0.789 g/mL, respectively.

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Correct Answer
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Correct Answer
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To prepare a diluted solution from a con...
View Answer

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To calculate the molarity of the solutio...
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If the molar mass of a substance is 20.0 g/mol, what is the mass of 4.01 × 10²³ molecules of the substance?

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How many atoms of iron are in 26.5 g of Fe₂O₃? Express your answer as a multiple or a fraction of Avogadro's number, N_A.

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To determine the number of iron atoms in...
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