A) How much heat needes to be taken from 0.5 kg of ethyl alcohol as a gas at its
ID: 2122682 • Letter: A
Question
A) How much heat needes to be taken from 0.5 kg of ethyl alcohol as a gas at its boiling point of 78 C to a solid at its freezing point -114 C if the latent heat of vaporization is 850,000 J/kg and its latent heat of fusion is 104,000 J/kg and the specific heat is 2400 J?
B) If a piece of irion (c=450 J/ kg C) at 65 C is dropped into 0.250 kg of ethyl acohol at 25 C and the final temperature of the two comes to 35 C what was the mass of the poece of iron?
C) if 0.35 kg of solid ethyl alcohol at -114.0 C is put in a large wll insulated jug holding 2.5 kg of liquid ethyl alcohol initially at 35 C what will the final temperature be after all the solid form has melted and come to equilibrium?
Explanation / Answer
A)
heat required Q = m*Lv + m*c*dT + m*Lf
Q = 0.5*850000 + 0.5*2400 + 0.5*104000
Q = 496200 J
B)
m*450*(65-35) = 0.25*2400*(35-25)
m = 0.444 kg
C)
0.35*104000 + 0.35*2400*(T-0) = 2.5*2400*(35-T)
T = 25.38 degrres centigrade