Question

what is the mass of a sample containg 1.50 x 10^23 molecules of NH3?

Answer 1

ANSWER:

Number of molecules of ammonia = 1.50 x 1023

Number of molecules in 1 mole = 6.022 x 1023

So, number of moles of ammonia = (1.50 x 1023)/(6.022 x 1023) = 0.25 moles

Molecular weight of ammonia = 17.031 g/mol

So, mass of ammonia = (molar mass) x (number of moles)

= (17.031 g/mil) x (0.25 mole)

= 4.26 grams

Hence, mass of a sample containing 1.5 x 1023 molecules of ammonia is 4.26 grams.