Question #7a48b

1 Answer
Apr 22, 2015

The size of your balloon will remain unchanged.

This time, only pressure is kept constant. You can use the ideal gas law equation to determine what's going to happen to the balloon.

So, for the initial state, you'd get

P * V_1 = n_1 * R * T_1PV1=n1RT1 color(blue)((1))(1)

The final state of the balloon will have

P * V_2 = n_2 * R * T_2PV2=n2RT2 color(blue)((2))(2)

Since you know that the number of moles is halved and the temperature is doubled, you can write

n_2 = n_1/2n2=n12 and T_2 = 2 * T_1T2=2T1

Plug this into equation color(blue)((2))(2)

P * V_2 = n_1/2 * R * 2T_1PV2=n12R2T1

Now divide equation color(blue)((1))(1) by equation color(blue)((2))(2) to get a relationship between the two volumes

(color(blue)((1)))/(color(blue)((2))) => (cancel("P") * V_1)/(cancel("P") * V_2) = (cancel(n_1) * cancel("R") * cancel(T_1))/(cancel(n_1)/2 * cancel("R") * 2cancel(T_1))

V_1/V_2 = 1/(1/2) * 1/2 = 2 * 1/2 = 1

This implies that

color(green)(V_2 = V_1)

The decrease in volume caused by the fact that you have less moles of gas is compensated by the doubling in temperature.