Ammonia combusts in oxygen according to the equation
4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)
A well-mixed gas sample in a constant-volume container has the following measured concentrations. All concentrations are in mol L⁻¹.
Time (s)
[NH₃]
[O₂]
[NO]
[H₂O]
0
0.200
0.300
0.000
0.000
120
0.160
———
———
———
240
0.120
———
0.080
———
Respond to the following prompts.
a. Determine [O₂] at 120 s and at 240 s, and enter the values in the table.
b. Determine [NO] at 120 s and [H₂O] at both 120 s and 240 s, and enter the values in the table.
c. Using your completed table, calculate the average rate of disappearance of O₂ (in mol L⁻¹ s⁻¹) between 120 s and 240 s.