Question

The partial pressures of the gases in the container are monitored at constant temperature and recorded in the table below. At time t4, is the rate of the reverse reaction greater than, less than, or equal to the rate of the forward reaction? At equilibrium, the container holds fewer molecules of which gas, Cl2(g) or O2(g) ?
time - PCl2 (atm) - PO2 (atm) - PCl2O (atm)
t0 - 0.50 - 0.50 - 0.0
t1 - 0.42 - 0.46 - 0.08
t2 - 0.36 - 0.43 - 0.14
t3 - 0.32 - 0.41 - 0.19
t4 - 0.29 - 0.39 - 0.22
t5 - 0.27 - 0.38 - 0.23
t6 - 0.26 - 0.37 - 0.24
t7 - 0.25 - 0.38 - 0.25
t8 - 0.25 - 0.38 - 0.25
t9 - 0.25 - 0.38 - 0.25

Answer 1

I assume the time intervals are the same; i.e., 1 sec or 2 sec or 3 sec etc.
rate of the rxn = delta pO2/delta time = ?
Follow O2 down the chart.
rate from t = 0 to t = 1 is 0.04
t1 to t2 = 0.03
t2 to t3 = 0.02
t3 to t4 = 0.02
t4 to t5 = 0.01
Since the rate of the forward reaction from t3 to t4 and from t4 to t5 is positive, then the forward reaction is faster than the reverse so the reverse reaction is less than the forward reaction.
For the gas with the fewest molecules, I would do the following.
From t9 that looks like equilibrium so lowest pressure has fewest moles and fewest moles will have fewest molecules. Which has the fewest moles?

Answer 2

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