Ans: Final volume = 25.0 ml
<u>Given:</u>
Initial volume V1 = 50.0 ml
Initial pressure P1 = 20.0 atm
Final pressure P2 = 40.0 atm
<u>To determine:</u>
The final volume V2
<u>Explanation:</u>
Ideal gas equation: PV = nRT
under constant temperature, T and number of moles n we have:
PV = constant
or, P1V1 = P2V2
V2 = P1V1/P2 = 20*50/40 = 25 ml.
Answer:
151 g/mol
Explanation:
In order to solve this problem we need to keep in mind the formula for the <em>boiling point elevation</em>:
Where:
- ΔT is the temperature difference between the boiling point of the solution and that of pure water. 100.37 °C - 100.00 °C = 0.37 °C.
- <em>m</em> is the molarity of the solution
- i is the van't Hoff factor. As the solute is a nonelectrolyte, the factor is 1.
Input the data and <u>calculate </u><em><u>m</u></em>:
- 0.37 °C = 0.51 °C/m * <em>m</em> * 1
We now can <u>calculate the number of moles of the substance</u>, using the <em>definition of molarity</em>:
- molarity = moles of solute / kg of solvent
In this case kg of solvent = 90.0 g / 1000 = 0.090 kg
- 0.72 m = moles / 0.090 kg
Finally we <u>calculate the molar mass</u>, using the <em>number of moles and the mass</em>:
- 9.81 g / 0.065 mol = 151 g/mol
