How Is The Molar Mass Of A Substance Determined?

1. What is the molar mass of Carbon?

6 g/mol

12.01 g/mol

19.00 g/mol

1.01 g/mol

The molar mass of a substance is determined by the average atomic mass according to the periodic table. The molar mass of carbon is 12.01 g/mol

Explanation

The molar mass of a substance is determined by the average atomic mass according to the periodic table. The molar mass of carbon is 12.01 g/mol

2. What is the molar mass of CH₄ (methane)?

12.01 g/mol

13.02 g/mol

16.05 g/mol

32.10 g/mol

The molar mass of a substance is determined by the average atomic mass according to the periodic table. There is 1 carbon in CH4 (methane) and 4 hydrogen:
Carbon 1 (12.01) + Hydrogen 4(1.01) = 16.05 g/mol

Explanation

The molar mass of a substance is determined by the average atomic mass according to the periodic table. There is 1 carbon in CH4 (methane) and 4 hydrogen:
Carbon 1 (12.01) + Hydrogen 4(1.01) = 16.05 g/mol

3. What is the molar mass of (NH₄)₂CO₃ (Ammonium carbonate)?

96.11 g/mol

82.10 g/mol

106.11 g/mol

43.01 g/mol

Molar mass is the mass of one mole of the substance. The molar mass of a substance is determined by the average atomic mass according to the periodic table. CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses. This means there are 2 nitrogen, 8 hydrogen (4 x 2), 1 carbon and 3 oxygen in this compound.
Nitrogen 2(14.01) + Hydrogen 8 (1.01) + Carbon 1 (12.01) + Oxygen 3(16.00) = 96.11 g/mol

Explanation

Molar mass is the mass of one mole of the substance. The molar mass of a substance is determined by the average atomic mass according to the periodic table. CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses. This means there are 2 nitrogen, 8 hydrogen (4 x 2), 1 carbon and 3 oxygen in this compound.
Nitrogen 2(14.01) + Hydrogen 8 (1.01) + Carbon 1 (12.01) + Oxygen 3(16.00) = 96.11 g/mol

4. What is the molecular mass of Cu₃(PO₄)₂?

253.49 g/mol

380.59 g/mol

110.22 g/mol

348.59 g/mol

Molar mass is the mass of ONE mole of a substance regardless of how many moles there are in the equation. CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses.
This means there are 3 Coppers, 2 Phosphorus, 8 oxygen:
Copper 3 (63.55) + Phosphorus 2(30.97) + 8 (16.00) = 380.59 g/mol

Explanation

Molar mass is the mass of ONE mole of a substance regardless of how many moles there are in the equation. CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses.
This means there are 3 Coppers, 2 Phosphorus, 8 oxygen:
Copper 3 (63.55) + Phosphorus 2(30.97) + 8 (16.00) = 380.59 g/mol

5. What is the molecular mass of Aluminum nitrate Al(NO₃)₃from this equation: 2Al(s) + 3Fe(NO₃)₂(aq) à 3Fe(s) + 2Al(NO₃)₃(aq)

213.01 g/mol

335.98 g/mol

56.99 g/mol

141.01 g/mol

(s) means solid and (aq) means aqueous.
Molar mass is the mass of ONE mole of a substance regardless of how many moles there are in the equation. So, ignore the “2” in front of Al(NO3)3
CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses.
This means there is 1 Aluminum, 3 Nitrogen, 9 oxygen (3 x 3)
The molar mass of a substance is determined by the average atomic mass according to the periodic table.
Aluminum 1 (26.98) + Nitrogen 3 (14.01) + Oxygen 9 (16.00) = 213.01 g/mol

Explanation

(s) means solid and (aq) means aqueous.
Molar mass is the mass of ONE mole of a substance regardless of how many moles there are in the equation. So, ignore the “2” in front of Al(NO3)3
CAUTION: The parentheses indicates that everything within the parentheses is MULTIPLIED by the subscript outside of the parentheses.
This means there is 1 Aluminum, 3 Nitrogen, 9 oxygen (3 x 3)
The molar mass of a substance is determined by the average atomic mass according to the periodic table.
Aluminum 1 (26.98) + Nitrogen 3 (14.01) + Oxygen 9 (16.00) = 213.01 g/mol