Chemistry question II

[Awuah29]

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Heh guys ,
Here another Chem question from topscore
What is the final pressure of a gas that expands from 2L at 10 C to 20 L at 100, if its pressure was initially 6 atm?
I know the solution , but I used the formula P1P2/P2V2 and did not get the answer

Another one
If the Kb of the solvent is 3.51 C/m and the boiling point of the pure solvent is 70.4 C, then what is the boiling point of the 4 m solution of the solute dissolved in the solvent. I used Kbm to solve
Thanks 😀

 

[ems5184]

For that first one, use P1V1/T1 = P2V2/T2 and that should be rearranged to solve for P2 and you should get the answer.

For the second one, just use deltaT = Kb*m so plug in 3.51 for Kb and 4 for m and you get about 14. The bp of the pure solvent is 70.4, so you have to add this 14 degrees to it since it is boiling point elevation and the addition of a solute will raise the bp. So the final answer should be 84.4, hope this helps.