a volume of nitrogen is collected over water at 25 degree celsius, the pressure in the lab is 757mmhg. what is the pressure exerted by the Nitrogen?

Question

need help figuring out what equation to use, and need a good explanation of why and how it works in laymens terms. got lost in chemistry class sometime last week, and need help cataching back up! have no idea what's going on, and can't get help via book or instructor. been on kahnacademy but was not very helpful with this problem or questions about orbitals.

Answer 1

Hello Liz, thank you for your question!

The formula here is actually fairly simple once you know what you’re looking for! You want to use the formula

Pressure(total) = Pressure(Nitrogen) + Pressure(Water)

So we’re given the Total Pressure of 757 mmHg and then at a temperature of 25 degrees Celsius the water would have a vapor pressure of 23.8 mmHg

Putting it all together then gives

757 mmHg = Pressure(Nitrogen) + 23.8 mmHg

Pressure(Nitrogen) = 733.2 mmHg

I hope that helps! :)