Answer:
Assumption:
1. The kinetic and potential energy changes are negligible
2. The cylinder is well insulated and thus heat transfer is negligible.
3. The thermal energy stored in the cylinder itself is negligible.
4. The process is stated to be reversible
Analysis:
a. This is reversible adiabatic(i.e isentropic) process and thus 
From the refrigerant table A11-A13

sat vapor
m=

b.) We take the content of the cylinder as the sysytem.
This is a closed system since no mass leaves or enters.
Hence, the energy balance for adiabatic closed system can be expressed as:
ΔE
ΔU
)
workdone during the isentropic process
=5.8491(246.82-219.9)
=5.8491(26.91)
=157.3993
=157.4kJ
Answer:
The initial temperature will be "385.1°K" as well as final will be "128.3°K".
Explanation:
The given values are:
Helium's initial volume, v₁ = 6 m³
Mass, m = 1.5 kg
Final volume, v₂ = 2 m³
Pressure, P = 200 kPa
As we know,
Work, 
On putting the estimated values, we get
⇒ 
⇒ 
⇒ 
Now,
Gas ideal equation will be:
⇒ 
On putting the values. we get
⇒ 
⇒ 
⇒
(Initial temperature of helium)
and,
⇒ 
On putting the values, we get
⇒ 
⇒ 
⇒
(Final temperature of helium)
Answer:
hmm
Explanation:
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hope this helps