Agas is initially at a pressure of 225 kpa and a temperature of 245 k in a container that is 4.5 l. if the gas is compressed to a volume of 2.1 l and the temperature changes to 275 k, what is the new pressure?

Use the ideal gas equation PV=nRT. You can compare before and after using P1V1/n1T1=P2V2/n2T2. Since the number of moles remains constant you can disregard moles from the equation and use pressure, volume and temp. Make sure your pressure is converted to atmospheres, your volume is in liters, and your temperature is in kelvins.

While unproven, it uses facts to support part of a conclusion. it is still factual and has predictive power, however.