In this example, we apply the ideal gas law. Our problem reads, "At what temperature in degrees Celsius will 65.6 grams of oxygen gas occupy 100.0 liters at a pressure of 752 torr?" We're given the conversion factor from torr to atmospheres. We can start with the ideal gas law, where P is pressure, V is volume, n is the moles of gas, R is the ideal gas law constant, and T is absolute temperature. Rearranging for temperature, we get pressure times volume divided by moles of gas and the ideal gas law constant. In this equation, pressure needs to be in atmospheres, so we use dimensional analysis to convert from 752 torr to atmospheres using the conversion factor given in the problem. Completing the calculation, we get 0.989 atmospheres. We also need to use dimensional analysis to convert from grams of oxygen gas to moles of oxygen gas. Oxygen is 1 of our 7 naturally occurring diatomic elements, so when we see oxygen gas, it almost always means O2. Completing the calculation, we have 2.05 moles of oxygen gas. We can substitute these into the ideal gas law equation. Volume is already given in liters in the problem, and the ideal gas law constant is 0.08206 liter atmospheres per mole Kelvin. Completing the calculation, we get 588 Kelvin. To convert this to degrees Celsius, we subtract 273 to get 315 degrees Celsius.