Question

a glass jar contains 1.7 g of ammonia gas. calculate the following;

1) molar mass of ammonia
2) how many moles of ammonia are present in the gas jar?
3) how many molecules of ammonia are present in the sample?

Answer 1

hope this helps you....

Answer 2

Given: A glass jar contains 1.7 g of ammonia gas.

To find: We have to find the molar mass of ammonia, moles of ammonia and molecules of ammonia.

Solution:

The chemical formula of ammonia is $NH_3$.

The atomic mass of N is 14 and H is 1.

The molar mass of ammonia is 14+3×1=17.

A glass jar contains 1.7 g of ammonia gas.

17-gram ammonia occupy 1 mole.

Thus 1.7-gram ammonia has 1.7/17=0.1 moles.

17 grams of ammonia has $6.023×10^{23}$ number of molecules.

1.7 grams of ammonia has $6.023×10^{23}×1.7/17=6.023×10^{22}$ number of molecules.

1. The molar mass of ammonia is 17 grams.
2. 1.7-gram ammonia has 0.1 moles.
3. 1.7 grams of ammonia has $6.023×10^{22}$ number of molecules.