"<span>using shaving cream, rather than shaving on dry skin" I believe this is the answer. coz rest of them would increase friction rather than decrease</span>
Hrxn = Q reaction / mol of reaction
mol of reaction = M * V = 10 * 1 = 10 mmol = 0.01 mol
Q water = m * C * (Tf - Ti)
= (10 + 10) (4.184) (26-20) = 502.08 J
Q reaction = - Q water = -502.08 J
Hrxn = -502.08 / (0.01) = - 50208 J = - 50.21 kJ/mol
Take the molality and multiply it by the Kb
0.75 × 0.52 = 0.39 C
then add the boiling pt to the 0.39
100 + 0.39 = 100.39 C
