What is the Kelvin (K) scale?
A temperature scale that is based on true molecular motion. Therefore, 0 K is the temperature at which zero molecular motion occurs, i.e. absolute zero. Kelvins can be converted to Celsius (
C) by using the formula K +273 = C, e.g. 0 K = -273 C.
What is the connection between pressure and a simple mercury barometer?
Pressure is simply how hard something pushes onto something else and can be measured by a barometer (from Greek baros ``weight'' and metron ``measure"). Mercury (Hg) is a liquid metal at room temperature that is quite dense. This proves to be a useful combination of properties because a relatively small volume can be used in a barometer to show small changes in pressure. So, when you get your blood pressure measured at the doctor, Hg is used in the barometer to show blood pressure changes by displacing the Hg column for the given pressure. If a less-dense substance were used, then the barometer ``column'' would have to be much taller to reveal similar pressure changes.
What is the molar volume of a gas at 0C at 1 atm?