An ideal gas is contained in a container with a volume of 2.50 L at a temperature of 78.0°C and a pressure of 2.00 atm. What is the new volume the gas will occupy when the pressure is reduced to 1.50 atm and temperature is increased to 92.0 °C ? A.3.47 L

B.3.21 L

C.1.95 L

D. 1.80 L

E.2.10 L

Solution:

We can use combined gas law when we are told that either pressure, volume or temperature of an ideal gas changed and are asked to find a new value for one of the variables.

P1V1 = P2V2

n1T1 n2T2

Let's look at the given:

V1= 2.50L

T1 = 78°C +273.15 = 351.15K

P1 = 2.00atm

V2= ?

P2 = 1.5atm

T2 = 92°C +273.15 = 365.15K

The number of moles is staying the same, so we don't have to include n.

2.00atm*2.50L = V2 * 1.5atm

351.15K 365.15K

V2 = 3.466L A