A 100 mm-diameter vertical cylinder, closed by a piston, contains a combustible mixture at a temprature of 15
deg. C. The piston is free to move and its mass is such that the mixture pressure is 240X10^3 N/m2
; the upper surface
of the piston is exposed to the atmosphere. The mixture is ignited. As the reaction proceeds, the piston move
slowly upwards and heat transfer to the surroundings takes place. When the reaction is complete and the
temprature of the contents has been reduced to the initial value , 15 deg. C, it is found that the piston has moved
upwards a net distance of 85 mm and that the magnitude of the heat transfer to the surrounding is 4 kJ.
Evaluate the increase in the energy of the contents of the cylinder?
Answers
Answered by
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Answer:
422
Explanation:
Initially,
P
lower
=P
upper
+P
piston
5×
V
R×300
=5×
4V
R×300
+P
piston
P
piston
=(
V
5R×300
)×
4
3
............(1)
Finally,
P
lower
=P
upper
+P
piston
V
4RT
=
3V
4RT
+P
pistion
3V
8RT
=P
piston
...(2)
From equation (1) & and (2)
4
15
×
V
R×300
=
3V
8RT
⇒T=421.9K
Answer is 422.
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