Question

23. A certain sample of nitrogen gas consists of 9.26 1022 nitrogen atoms.

(a) How many moles of N atoms are present in this sample ?
(b) If the gas is entirely in molecular form, how many molecules are present in this
sample?
(c) What is the mass of the sample in gramme?
​

Answer 1

a) 0.154 moles of N2

b) 9.27 × 10^22 molecules

c) 4.312 g

Step-by-step explanation:

a)

1 mole of N2 contains 6.02 × 10^23 atoms

x moles of N2 contains 9.26 × 10^22 atoms

x= 9.26 ×10^22/6.02 × 10^23

x= 1.54 ×10^-1

x= 0.154 moles of N2

b)

1 mole of N2 contains 6.02 × 10^23 molecules

0.154 moles of N2 contains 0.154 moles × 6.02 × 10^23 = 9.27 × 10^22 molecules

c)

Molar mass of the nitrogen gas= 28 gmol^-1

Number of moles of nitrogen gas = 0.154 moles

Number of moles = mass/molar mass

0.154 moles= mass/28 gmol^-1

Mass= 0.154 moles × 28gmol^-1

Mass= 4.312 g