Question 1

There are 6 grams of carbon in 22 grams of carbon dioxide.

Accepted Answer

A) True 
 B)False

Question 2

The molecular formula is equal to the empirical formula multiplied by a whole number integer.

Accepted Answer

A) True 
 B)False

Question 3

How many hydrogen atoms are in 35.0 grams of hydrogen gas?

Accepted Answer

A)  4.25 × 1025
B)  2.09 × 1025
C)  2.12 × 1025
D)  1.05 × 1025
E)  none of the aboveF) A) and B)
G) A) and C)

Question 4

The simplest formula for hydrogen peroxide is HO.To determine its molecular formula,it is necessary to know

Accepted Answer

A)  the properties of hydrogen peroxide.
B)  the density of hydrogen peroxide.
C)  the molar mass of hydrogen peroxide.
D)  the number of moles of hydrogen peroxide in 1.00 g of the substance.
E)  none of the aboveF) C) and D)
G) A) and C)

Question 5

The correct formula for calculating mass percent of X in compound XY is:  
= Mass % X

Accepted Answer

A) True 
 B)False  False

Question 6

What is the molecular formula of a compound given the molar mass of the compound is 186.5 grams and the empirical formula is C2H7?

Accepted Answer

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

Question 7

Given that sodium chloride is 39.0% sodium by mass,how many grams of sodium chloride are needed to have 750.mg of Na present?

Accepted Answer

A)  1.92
B)  0.293
C)  1,920
D)  29.3
E)  none of the aboveF) A) and B)
G) A) and E)

Question 8

A chromium oxide compound contains 104.0 grams of chromium and 48.0 grams of oxygen.What is the most likely empirical formula of this compound?

Accepted Answer

A)  CrO
B)  CrO2
C)  CrO3
D)  Cr2O3
E)  Cr3O2F) None of the above
G) C) and E)

Question 9

Determine the empirical formula of a compound containing 60.3% magnesium and 39.7% oxygen.

Accepted Answer

A)  MgO
B)  MgO2
C)  Mg2O3
D)  Mg2O
E)  none of the aboveF) A) and B)
G) A) and C) A

Question 10

The number 6.022 × 1023 is six times larger than the number 6.022 × 1022.

Accepted Answer

A) True 
 B)False

Question 11

What is the value of n when the empirical formula is C3H5 and the molecular mass is 205.4 g/mol?

Accepted Answer

A)  0.02
B)  5
C)  10
D)  140
E)  none of the aboveF) A) and E)
G) A) and B)

Question 12

How many molecules of sulfur trioxide are in 78.0 grams?

Accepted Answer

A)  5.87 × 1023
B)  7.33 × 1023
C)  3.76 × 1027
D)  0.974
E)  none of the aboveF) A) and B)
G) A) and C)

Question 13

The numerical value of the mole is defined as being equal to the number of atoms in exactly 12 grams of pure carbon-12.

Accepted Answer

A) True 
 B)False

Question 14

Bauxite is an ore that contains the element aluminum.If you obtained 108 grams of aluminum from an ore sample that initially weighed 204 grams,what is the mass percent of aluminum in this bauxite ore?

Accepted Answer

A)  52.9
B)  15.6
C)  0.53
D)  47.1
E)  none of the aboveF) A) and E)
G) None of the above

Question 15

A molecule that has an empirical formula of HO and a molar mass of 34.02 gram must have a molecular formula of H2O2.

Accepted Answer

A) True 
 B)False  True

Question 16

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) B) and C)
G) A) and B)

Question 17

A 500.gram iron ore sample was determined to contain 242 grams of iron.What is the mass percent of iron in the ore?

Accepted Answer

A)  93.7
B)  48.4
C)  51.6
D)  32.6
E)  none of the aboveF) A) and D)
G) C) and E)

Question 18

What is the mass percent of carbon in oxalic acid,H2C2O4?

Accepted Answer

A)  2.24
B)  13.3
C)  26.7
D)  34.5
E)  none of the aboveF) C) and E)
G) A) and D)

Question 19

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 C)
G) A) and D)

Question 20

Determine the empirical formula of a compound containing 83% potassium and 17.0% oxygen.

Accepted Answer

A)  KO
B)  KO2
C)  K2O3
D)  K2O
E)  none of the aboveF) B) and C)
G) B) and E)

Exam 6: Chemical Composition

There are 6 grams of carbon in 22 grams of carbon dioxide.

Correct AnswerverifiedShow Answer

The molecular formula is equal to the empirical formula multiplied by a whole number integer.

Correct AnswerverifiedShow Answer

How many hydrogen atoms are in 35.0 grams of hydrogen gas?

Correct AnswerverifiedShow Answer

The simplest formula for hydrogen peroxide is HO.To determine its molecular formula,it is necessary to know

Correct AnswerverifiedShow Answer

The correct formula for calculating mass percent of X in compound XY is: = Mass % X

Correct AnswerverifiedFalse

What is the molecular formula of a compound given the molar mass of the compound is 186.5 grams and the empirical formula is C2H7?

Correct AnswerverifiedShow Answer

Given that sodium chloride is 39.0% sodium by mass,how many grams of sodium chloride are needed to have 750.mg of Na present?

Correct AnswerverifiedShow Answer

A chromium oxide compound contains 104.0 grams of chromium and 48.0 grams of oxygen.What is the most likely empirical formula of this compound?

Correct AnswerverifiedShow Answer

Determine the empirical formula of a compound containing 60.3% magnesium and 39.7% oxygen.

Correct AnswerverifiedA

The number 6.022 × 1023 is six times larger than the number 6.022 × 1022.

Correct AnswerverifiedShow Answer

What is the value of n when the empirical formula is C3H5 and the molecular mass is 205.4 g/mol?

Correct AnswerverifiedShow Answer

How many molecules of sulfur trioxide are in 78.0 grams?

Correct AnswerverifiedShow Answer

The numerical value of the mole is defined as being equal to the number of atoms in exactly 12 grams of pure carbon-12.

Correct AnswerverifiedShow Answer

Bauxite is an ore that contains the element aluminum.If you obtained 108 grams of aluminum from an ore sample that initially weighed 204 grams,what is the mass percent of aluminum in this bauxite ore?

Correct AnswerverifiedShow Answer

A molecule that has an empirical formula of HO and a molar mass of 34.02 gram must have a molecular formula of H2O2.

Correct AnswerverifiedTrue

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

Correct AnswerverifiedShow Answer

A 500.gram iron ore sample was determined to contain 242 grams of iron.What is the mass percent of iron in the ore?

Correct AnswerverifiedShow Answer

What is the mass percent of carbon in oxalic acid,H2C2O4?

Correct AnswerverifiedShow Answer

How many atoms are in 5.80 moles of He?

Correct AnswerverifiedShow Answer

Determine the empirical formula of a compound containing 83% potassium and 17.0% oxygen.

Correct AnswerverifiedShow Answer

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False

What is the molecular formula of a compound given the molar mass of the compound is 186.5 grams and the empirical formula is C₂H₇?

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A

The number 6.022 × 10²³ is six times larger than the number 6.022 × 10²².

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What is the value of n when the empirical formula is C₃H₅ and the molecular mass is 205.4 g/mol?

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A molecule that has an empirical formula of HO and a molar mass of 34.02 gram must have a molecular formula of H₂O₂.

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True

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What is the mass percent of carbon in oxalic acid,H₂C₂O₄?

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