Question

3. What is the theoretical yield of ammonia (in grams) if 15.85 grams of nitrogen

gas and 11.40 grams of hydrogen gas are allowed to react? (11 pts)

4. Based on your theoretical yield, what is the percent yield of ammonia if only 6.65 grams of ammonia is produced? (5 pts)

5. How much heat energy (in kJ) will be absorbed or released if 6.65 grams of

ammonia is produced? State whether the energy will be absorbed or released.

(7 pts)

Answer 1

Ans 3 :

The balanced reaction is given as :

N2 + 3H2 = 2NH3

Number of moles of nitrogen = 15.85 / 28.0134 = 0.566 mol

Number of moles of hydrogen = 11.40 / 2.016 = 5.66 mol

3 mol hydrogen needs 1 mol nitrogen

So 5.66 mol hydrogen will need = 5.66 / 3 = 1.88 mol nitrogen

Nitrogen is the limiting reagent

1 mol nitrogen makes 2 mol ammonia

So 0.566 mol nitrogen will make : 0.566 x 2 = 1.13 mol ammonia

theoretical yield of ammonia = mol x molar mass

= 1.13 x 17.03

= 19.3 grams