How will the rate of the direct and reverse reaction CH4 + H2O = CO + 3H2

How will the rate of the direct and reverse reaction CH4 + H2O = CO + 3H2 change if the volume of the system is increased by 1.5 times at a constant temperature?

For the gas-phase reaction CH4 + H2O = CO + 3H2, the rate of the forward reaction is u1 = k1 * [CH4] * [H2O], and the reverse one is u2 = k2 * [CO] * [H2] ^ 2 (we take water as gaseous, since there is no other indications). An increase in volume will lead to a decrease in the concentration of each substance by 1.5 times:

u1 ‘= k1 * [CH4] / 1.5 * [H2O] / 1.5 = (k1 * [CH4] * [H2O]) / 2.25;

u2 ‘= k2 * [CO] / 1.5 * ([H2] / 1.5) ^ 2 = (k2 * [CO] * [H2] ^ 2) / 3.375.

Thus, the speed of the forward reaction will decrease by 2, 25 times, and the reverse – by 3, 375 times.