Gases w and x react in a closed, rigid vessel to form gases y and 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) is initially present. The experiment is carried out at constant temperature. What is the partial pressure of z(g) when the partial pressure of w(g) has decreased to 1. 0 atm?.