Pressure Help Please

Question

A sample of gas is held at constant volume. If the absolute temperature of this sample of gas is doubled and the number of moles of this sample of gas is doubled, what happens to the pressure of the gas?

Answer 1

Using PV = nRT (ideal gas law) you can add in the following:

Rearrange to solve for P (pressure):

P = nRT / V

Then, double the moles (n) and double the temperature (T) with a constant volume (V):

P = (2n)R(2T) / V

Now, combine coefficents in the equation:

P = 4(nRT / V) = 4(P)

Thus, the increase in moles and increase in temperature leads to a 4 times increase in pressure.