W(g) + x(g) --> y(g) +z(g)
gases w and x react in a closed, rigid vessel to form gases yand z according to the equation above. the initial pressure of w(g)is 1.20 atm and that of x(g) is 1.60 atm. no y(g) or z(g) isinitially present. the experiment is carried out at constanttemperature. what is the partial pressure of z(g) when the partialpressure of w(g) has decreased to 1.0 atm?
a) 0.20 atm
b) 0.40 atm
c) 1.0 atm
d) 1.2 atm
e) 1.4 atm

A) 0.20 atm

Explanation:

Let's consider the following reaction.

W(g) + X(g) ⇄ Y(g) +Z(g)

We can find the partial pressure of Z at a time that we will call the equilibrium using an ICE chart. We identify 3 stages: Initial, Change and Equilibrium and complete each row with the pressure or change in pressure.

        W(g) + X(g) ⇄ Y(g) +Z(g)

I        1.20    1.60       0      0

C        -x        -x         +x     +x

E     1.20 -x  1.60 -x    x        x

At equilibrium, the partial pressure of W is 1.0 atm.

1.20 atm - x = 1.0 atm

x = 0.20 atm

The pressure of Z is x = 0.20 atm