# Average Atomic Masses Quiz

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| By Eddy8829
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Eddy8829
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Quizzes Created: 19 | Total Attempts: 54,970
Questions: 8 | Attempts: 249

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• 1.

### Calculate the relative formula mass for the compound: H2SO4

• A.

96

• B.

97

• C.

98

• D.

99

C. 98
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the compound. In this case, we have 2 hydrogen atoms (H) with an atomic mass of 1 each, 1 sulfur atom (S) with an atomic mass of 32, and 4 oxygen atoms (O) with an atomic mass of 16 each. Adding these up, we get (2*1) + 32 + (4*16) = 2 + 32 + 64 = 98. Therefore, the relative formula mass for the compound H2SO4 is 98.

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• 2.

### Calculate the relative formula mass for the compound: Fe2(SO4)3

• A.

399

• B.

400

• C.

401

• D.

402

B. 400
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the compound. In Fe2(SO4)3, there are 2 iron (Fe) atoms, 3 sulfate (SO4) ions, and a total of 12 oxygen (O) atoms. The atomic mass of iron is 56, the atomic mass of sulfur is 32, and the atomic mass of oxygen is 16. Therefore, the relative formula mass can be calculated as follows: (2 * 56) + (3 * (32 + (4 * 16))) = 112 + (3 * (32 + 64)) = 112 + (3 * 96) = 112 + 288 = 400.

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• 3.

### Calculate the relative formula mass for the compound: NAOH

• A.

39

• B.

40

• C.

41

• D.

42

B. 40
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the formula. In this case, NaOH is composed of one sodium atom (Na) with an atomic mass of 23, one oxygen atom (O) with an atomic mass of 16, and one hydrogen atom (H) with an atomic mass of 1. Adding these atomic masses together (23 + 16 + 1) gives a total of 40, which is the relative formula mass for NaOH.

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• 4.

### Calculate the relative formula mass for the compound: HNO3

• A.

63

• B.

64

• C.

65

• D.

66

A. 63
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the compound. In this case, the compound is HNO3 which consists of one hydrogen atom (atomic mass of 1), one nitrogen atom (atomic mass of 14), and three oxygen atoms (atomic mass of 16 each). Adding up these atomic masses gives us a total of 63, which is the correct answer.

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• 5.

### Calculate the relative formula mass for the compound: FeO

• A.

69

• B.

70

• C.

71

• D.

72

D. 72
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the compound. In this case, FeO is composed of one iron (Fe) atom with an atomic mass of 56 and one oxygen (O) atom with an atomic mass of 16. Adding these together, we get a relative formula mass of 72.

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• 6.

### Calculate the relative formula mass for the compound: CaCl

• A.

109

• B.

110

• C.

111

• D.

112

C. 111
Explanation
The relative formula mass (or molar mass) of a compound is the sum of the atomic masses of all the atoms in the formula. In this case, CaCl is composed of one calcium atom (Ca) and one chlorine atom (Cl). The atomic mass of calcium is approximately 40, and the atomic mass of chlorine is approximately 35.5. Adding these two atomic masses together gives a total of approximately 75.5. However, since the options provided are all integers, it is likely that the atomic mass of chlorine is rounded up to 36. Therefore, the relative formula mass of CaCl is approximately 40 + 36 = 76.

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• 7.

### Calculate the relative formula mass for the compound: C2H5OH

• A.

46

• B.

47

• C.

48

• D.

49

A. 46
Explanation
The relative formula mass (also known as the molar mass) is calculated by adding up the atomic masses of all the atoms in the compound. In this case, we have 2 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom. The atomic mass of carbon is 12.01 g/mol, the atomic mass of hydrogen is 1.01 g/mol, and the atomic mass of oxygen is 16.00 g/mol. Therefore, the relative formula mass of C2H5OH is (2 * 12.01) + (6 * 1.01) + 16.00 = 46.

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• 8.

### Calculate the relative formula mass for the compound: (NH4)2SO4

• A.

131

• B.

132

• C.

133

• D.

134

B. 132
Explanation
The relative formula mass of a compound is calculated by adding up the atomic masses of all the atoms in the compound. In this case, (NH4)2SO4, we have 2 ammonium ions (NH4+) and one sulfate ion (SO4^2-). The atomic mass of nitrogen (N) is 14, hydrogen (H) is 1, sulfur (S) is 32, and oxygen (O) is 16. Therefore, the total relative formula mass is (2*14) + (8*1) + 32 + (4*16) = 132.

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• Current Version
• Mar 21, 2023
Quiz Edited by
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• Mar 06, 2016
Quiz Created by
Eddy8829

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