Question

If 100⋅mL of ammonia gas are decomposed into its constituent elements what volumes of dinitrogen, and dihydrogen would result?

Answer 1

Step 1. Write the balanced chemical equation.

4NH₃(g) + 7O₂(g) → 4NO₂(g) + 6H₂O(l)

Step 2. Convert mass of NH₃ → moles of NH₃ → moles of NO₂.

100 g NH₃ ×

1

mol NH

3

17.03

g NH

3

×

4

mol NO

2

4

mol NH

3

= 5.872 mol NH₃ (3 significant figures +

1 guard digit)

Step 3. Use the Ideal Gas Law to calculate the volume of NO₂.

P

V

=

n

R

T

V

=

n

R

T

P

=

5.872

mol

×

8.314

kPa⋅L⋅K

−

1

mol

−

1

×

273

K

100

kPa

= 133 L