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# Partial pressure

This video explores the concept of partial pressure in a gas mixture. It explains how to calculate the total pressure and the partial pressures of each gas in the mixture using the ideal gas law and mole fractions. The video emphasizes the importance of considering the number of particles, not just the mass, when calculating pressure.
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## Want to join the conversation?

• Was that math right?? he didn't divide the whole problem by 4, only the 100.
• We get the same answer if we work out the math both ways. (100*8.314*273)/4 = 56743.05 and 25*8.314*273 = 56743.05
(1 vote)
• Does the partial pressure of each gas change at different rates with a change in temperature when using the ideal gas law?
• Remember, partial pressure is dependent on the mole fraction of the respective molecules. The percentage of partial pressure for which each molecule is responsible is going to stay the same as long as the mole fraction is kept constant, even if you increase temperature. Hope it helps.
• is R given in the mcat?
• Pressure is Force divided by Area too...and force = mass * acceleration... So shouldn't pressure also not depend on the mass of the particles?
• It ia the kinetic energy that counts and that, in the end, is an expression of the temperature.
Smaller particles, like H2, travel faster.
In othwer words, particles have different speeds but equal kinetic energies ~ T.
(1 vote)
• Why do we use the number of moles as percentages for partial pressure instead of the percentages they give us (i.e., why do we use 50% for N2 instead of the 66.67% they give us at the start?)
(1 vote)
• Is it like,lower the mass number,more the diffusion rate?
(1 vote)
• Is the final equation (the one that says that the total pressure is equal to the summation of each partial pressure of each gas present in the mixture), only valid for ideal gasses ?
(1 vote)
• No, this equation works for anything. For example when you mix oil and water, the total pressure of the system will be equal to the summation of the individual parts. This explains why oil and water when mixed have a lower boiling point than either part separately.
(1 vote)
• Why is 0 degree celcius standard temperature?