Question

Short Response

Directions: Base your answers to questions 6 and 7 on the information below and your knowledge of chemistry.
Ammonia, NH3(g), can be used as a substitute for fossil fuels in some internal combustion
engines. The reaction between ammonia and oxygen in an engine is represented by
the unbalanced equation below.
NH3(g) + O₂(g) → N₂(g) + H₂O(g) + energy
6. Balance the equation in the space below for the reaction of ammonia and oxygen, using the
smallest whole-number coefficients.
7. Show a numerical setup for calculating the mass, in grams, of a 4.2-mole sample of 0₂. Use 32
g/mol as the gram-formula mass of 0₂.

Answer 1

6.)

7.) 134.4 g O₂

Step-by-step explanation:

The unbalanced equation:

NH₃ (g) + O₂ (g) ---> N₂ (g) + H₂O (g) + energy

Reactants: 1 nitrogen, 3 hydrogen, 2 oxygen

Products: 2 nitrogen, 2 hydrogen, 1 oxygen

The balanced equation:

4 NH₃ (g) + 3 O₂ (g) ---> 2 N₂ (g) + 6 H₂O (g) + energy

Reactants: 4 nitrogen, 12 hydrogen, 6 oxygen

Products: 4 nitrogen, 12 hydrogen, 6 oxygen

To convert from moles to grams, you need to multiply the starting value (4.2 moles) by the molar mass (32.00 g/mol). The molar mass can serve as a conversion because it technically means there are 32.00 grams O₂ per every 1 mole. It is important to arrange this ratio in a way that allows for the cancellation of units (the desired unit should be in the numerator).

4.2 moles O₂ 32.00 g
-------------------- x ---------------- = 134.4 g O₂
1 mole