Answer:
3.55atm
Explanation:
We will apply Boyle's law formula in solving this problem.
P1V1 = P2V2
And with values given in the question
P1=initial pressure of gas = 1.75atm
V1=initial volume of gas =7.5L
P2=final pressure of gas inside new piston in atm
V2=final volume of gas = 3.7L
We need to find the final pressure
From the equation, P1V1 = P2V2,
We make P2 subject
P2 = (P1V1) / V2
P2 = (1.75×7.5)/3.7
P2=3.55atm
Therefore, the new pressure inside the piston is 3.55atm
Answer: the boiling point elevation constant is 
Explanation:
Elevation in boiling point is given by:

= Elevation in boling point
i= vant hoff factor = 1 (for non electrolyte)
=boiling point constant = ?
m= molality

Weight of solvent (diethylether)= 330 g = 0.33 kg
Molar mass of solute (benzophenone)= 182 g/mol
Mass of solute (benzophenone) = 38.2 g


Thus the boiling point elevation constant is 
N= m/v n=0.077/.200 = 0.385