Question

What mass of n2 gas will contain same number of molecules as 1.8 gram of water

Answer 1

1.8 g of H2O
molar mass of H2O =1*2 +16 =18 ; given mass =1.8g
number of moles = given mass /molar mass
=1.8/18 = 1/10 = 0.1 moles


let mass of n2 gas be (x) grams
as both have same number of molecules so both will have same number of moles.

molar mass of n2 = 14*2 =28 ;given mass = ( x ) grams n = 0.1 moles

n= given mass / molar mass
so given mass = n * molar mass
x = 0.1 * 28
x = 2.8 grams
HENCE THE MASS OF N2 REQUIRED IS 2.8 GRAMS.