What are some examples of partial pressures?
The best example is the pressure exerted by the air we breathe.
By Dalton's law of partial pressures, the total pressure is the sum of the partial pressures of each component in the gaseous mixture. At the moment, you and I are breathing air at a pressure of around 1 atmosphere (if you lived in Denver, would this be true?). This is composed of 78% nitrogen, 21% oxygen, 1% argon, and some (increasing quantity) of carbon dioxide. Therefore we are breathing pressures of 0.78 atm