Question 1

How many atoms are in 5.80 moles of He?

Accepted Answer

A)  6.02 × 1023
B)  1.03 × 1023
C)  4.00
D)  3.49 × 1024
E)  none of the aboveF) A) and B)
G) B) and D)

Question 2

A 15.5 gram sample of diphosphorous pentoxide contains how many grams of phosphorous?

Accepted Answer

A)  3.38
B)  1.69
C)  6.76
D)  13.5
E)  none of the aboveF) C) and D)
G) A) and B)

Question 3

If 3.011 × 
 
        Molecules have a mass of 20.04 grams,what is the molar mass of this substance? A) 40.08 g/mol B) 10.02 g/mol C) 20.04 g/mol D) 6.658 ×   G/mol E) none of the above" class="answers-bank-image d-inline" rel="preload" >
Molecules have a mass of 20.04 grams,what is the molar mass of this substance?

Accepted Answer

A)  40.08 g/mol
B)  10.02 g/mol
C)  20.04 g/mol
D)  6.658 ×        Molecules have a mass of 20.04 grams,what is the molar mass of this substance? 
A)  40.08 g/mol 
B)  10.02 g/mol 
C)  20.04 g/mol 
D)  6.658 ×   G/mol 
E)  none of the above" class="answers-bank-image d-inline" rel="preload" >G/mol
E)  none of the aboveF) A) and D)
G) A) and B)

Question 4

One mole of oxygen gas has a mass of ________ g.

Accepted Answer

A)  16.0
B)  32.0
C)  6.022 × 1023
D)  8
E)  none of the aboveF) All of the above
G) A) and E)

Question 5

Which of the following compounds has the highest mass percent of "O"?

Accepted Answer

A)  MnO
B)  MnO2
C)  Mn2O3
D)  Mn3O2
E)  none of the aboveF) C) and D)
G) A) and B)

Question 6

Water is 11.2% hydrogen by mass.

Accepted Answer

A) True 
 B)False

Question 7

One mole of chlorine gas has a mass of 35.45 grams.

Accepted Answer

A) True 
 B)False

Question 8

The empirical formula for C6H6 is C3H3.

Accepted Answer

A) True 
 B)False

Question 9

Calculate the molar mass of calcium nitrate.

Accepted Answer

A)  136.03 g/mol
B)  102.09 g/mol
C)  132.10 g/mol
D)  164.10 g/mol
E)  none of the aboveF) None of the above
G) A) and C)

Question 10

An empirical formula gives the specific number of each type of atom in a molecule.

Accepted Answer

A) True 
 B)False

Question 11

What is the molecular formula of a compound given the molar mass of the compound is 2H7? A) C4H14 B) C3H21 C) C2H7 D) C2H14 E) none of the above" class="answers-bank-image d-inline" rel="preload" >
And the empirical formula is C2H7?

Accepted Answer

A)  C4H14
B)  C3H21
C)  C2H7
D)  C2H14
E)  none of the aboveF) A) and B)
G) B) and E)

Question 12

How many moles are there in 82.5 grams of iron?

Accepted Answer

A)  4.97 × 1025
B)  55.85
C)  0.677
D)  1.48
E)  none of the aboveF) C) and D)
G) B) and E)

Question 13

How many atoms of lithium are in 18.7 g?

Accepted Answer

A)   
B)   
C)   
D)   
E)  none of the aboveF) A) and E)
G) A) and D)

Question 14

What is the molecular formula of a compound given the molar mass of the compound is 30.04 gram and the empirical formula is NH?

Accepted Answer

A)  NH
B)  N2H2
C)  N2H6
D)  N4H4
E)  none of the aboveF) B) and C)
G) B) and E)

Question 15

The empirical formula mass is 18.0 and the molecular formula mass is 90,therefore n = 5.

Accepted Answer

A) True 
 B)False

Question 16

How many moles of Pb are in 4.71 × 1021 Pb atoms?

Accepted Answer

A)  0.00782
B)  2.84 × 1045
C)  207.2
D)  6.022 × 1023
E)  none of the aboveF) C) and E)
G) A) and D)

Question 17

Calculate the molar mass of ammonium carbonate.

Accepted Answer

A)  78.05 g/mol
B)  88.05 g/mol
C)  96.09 g/mol
D)  112.09 g/mol
E)  none of the aboveF) A) and E)
G) B) and E)

Question 18

An empirical formula gives the smallest whole number ratio of each type of atom in a molecule.

Accepted Answer

A) True 
 B)False

Question 19

The mass of 2.0 moles of H2O is greater than the mass of 1.0 mole of CO2.

Accepted Answer

A) True 
 B)False

Question 20

Avogadro's Number is 6.022 × 1023.

Accepted Answer

A) True 
 B)False

Exam 6: Chemical Composition

What is the molecular formula of a compound given the molar mass of the compound is And the empirical formula is C2H7?

Correct AnswerverifiedShow Answer

The empirical formula mass is 18.0 and the molecular formula mass is 90,therefore n = 5.

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Avogadro's Number is 6.022 × 1023.

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How many moles of Pb are in 4.71 × 1021 Pb atoms?

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How many atoms of lithium are in 18.7 g?

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How many moles are there in 82.5 grams of iron?

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The mass of 2.0 moles of H2O is greater than the mass of 1.0 mole of CO2.

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Calculate the molar mass of ammonium carbonate.

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An empirical formula gives the smallest whole number ratio of each type of atom in a molecule.

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Calculate the molar mass of calcium nitrate.

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One mole of chlorine gas has a mass of 35.45 grams.

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Which of the following compounds has the highest mass percent of "O"?

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How many atoms are in 5.80 moles of He?

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Water is 11.2% hydrogen by mass.

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A 15.5 gram sample of diphosphorous pentoxide contains how many grams of phosphorous?

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If 3.011 × Molecules have a mass of 20.04 grams,what is the molar mass of this substance?

Correct AnswerverifiedShow Answer

The empirical formula for C6H6 is C3H3.

Correct AnswerverifiedShow Answer

An empirical formula gives the specific number of each type of atom in a molecule.

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One mole of oxygen gas has a mass of ________ g.

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What is the molecular formula of a compound given the molar mass of the compound is 30.04 gram and the empirical formula is NH?

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What is the molecular formula of a compound given the molar mass of the compound is And the empirical formula is C₂H₇?

Correct Answer
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Avogadro's Number is 6.022 × 10²³.

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How many moles of Pb are in 4.71 × 10²¹ Pb atoms?

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The mass of 2.0 moles of H₂O is greater than the mass of 1.0 mole of CO₂.

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The empirical formula for C₆H₆ is C₃H₃.

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