Question

3mL of ethonal is added to a 125mL Erlenmeyer flask with a stopper

Calculate the preasure of just the air in the flask. The volume and number of moles air stays constant. Please just show how to do one calculation so I can so the rest on my own. Please and thank you.

Temp(C).      Pressure

before 3mL ethonal

22.5.             103.05

after 3mL ethanol

22.5.             107.03

26.1.              110.05

28.7               111.96

Answer 1

To calculate just the air pressure, note that air pressure before adding ethanol - which 103.05

at different temperatures you can calculate it using the relationship, P1/T1 = P2/T2

and substracting the air pressure from the total pressure given after adding 3ml ethanol at different temperatures results the pressure of just ethanol, because of the relaltionship total pressure = sum of the partial pressure of the gases.

		P air	P ethanol
295.5	107.03	103.05	3.98
299.1	110.05	104.3054315	5.7445685
301.7	111.96	105.212132	6.747868