Molar mass Knowledge-Based Download PDF

Questions

1. 1.

   What is the mass, in grams, of 0.300 mol of sodium phosphate, $\text{Na}_3\text{PO}_4$? (Molar masses: $\text{Na} = 22.99\text{ g/mol}$, $\text{P} = 30.97\text{ g/mol}$, $\text{O} = 16.00\text{ g/mol}$)

   • A) 546 g
   • B) 164 g
   • C) 35.4 g
   • D) 49.2 g
2. 2.

   Given equal 20.0 g samples of each of the following pure gases, which sample contains the greatest number of moles?

   • A) $\text{H}_2$ (molar mass = 2.02 g/mol)
   • B) $\text{CH}_4$ (molar mass = 16.04 g/mol)
   • C) $\text{N}_2$ (molar mass = 28.02 g/mol)
   • D) $\text{CO}_2$ (molar mass = 44.01 g/mol)
3. 3.

   A sample containing $1.505 \times 10^{23}$ molecules of an unknown gas has a mass of 11.0 g. Given that Avogadro's constant is $6.022 \times 10^{23}\text{ mol}^{-1}$, what is the molar mass of the gas?

   • A) 11.0 g/mol
   • B) 22.0 g/mol
   • C) 88.0 g/mol
   • D) 44.0 g/mol
4. 4.

   A 0.500 mol sample of a metal carbonate, $\text{XCO}_3$, has a mass of 50.0 g. Given that the molar masses of carbon and oxygen are 12.0 g/mol and 16.0 g/mol respectively, what is the molar mass of element X?

   • A) 20.0 g/mol
   • B) 28.0 g/mol
   • C) 40.0 g/mol
   • D) 60.0 g/mol
5. 5.

   What is the molar mass of ammonium phosphate, $(\text{NH}_4)_3\text{PO}_4$, given the atomic masses of nitrogen (14.01 g/mol), hydrogen (1.01 g/mol), phosphorus (30.97 g/mol), and oxygen (16.00 g/mol)?

   • A) 113.02 g/mol
   • B) 121.10 g/mol
   • C) 141.02 g/mol
   • D) 149.12 g/mol