Question

2. (05.02 MC)
What is the mass of a sample of NHz containing 7.20 x 1024 molecules of NH3? (5 points)
161 grams
187 grams
203 grams
214 grams

HELPPPPPP

Answer 1

Solution :

We know, molecular mass of NH₃ is , M = 17 g/mol .

Number of moles of NH₃ in 7.2 × 10²⁴ are :

$n = \dfrac{7.2 \times 10^{24}}{6.022 \times 10^{23}}\\\\n = 11.96\ moles$

So, mass of NH₃ present in 11.96 moles is :

m = 11.96 × 17 gram

m = 203.32 gram

Hence, this is the required solution.