Advertisements
Advertisements
Question
Give the expression for work done by the gas.
Advertisements
Solution
When a gas expands against pressure, it does work on the surroundings. The work done in expansion for volume V1 to V2 is given by
W = `int_("V"_1)^("V"_2) "PdV"`
If the pressure remains constant during expansion,
Then W = P(V2 – V1) = P∆V
If the volume remains constant, then W = 0.
If there is no external pressure, then no work is done. For example, when a gas expands freely in a vacuum, no work is done by it.
APPEARS IN
RELATED QUESTIONS
An ideal gas is taken from (Pi, Vi) to (Pf, Vf) in three different ways. Identify the process in which the work done on the gas the most.
Define the internal energy of the system.
Define one calorie.
Did joule converted mechanical energy to heat energy? Explain.
Give the sign convention for Q and W.
Define the quasi-static process.
When a system absorbs 8 kJ of heat and does 2.2 kJ of work on surrounding, calculate the internal energy change.
A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 Bar from an initial volume of 2.5L to a final volume of 4.5L The change in internal energy, ΔU of the gas will be ______.
The value of Δ U is ______ when 2 kJ of heat is released and 6 kJ of work is done on the system.
Calculate the change in internal energy of a gas if a gas is compressed adiabatically from 25 dm³ to 15 dm³ at constant external pressure of 4 bar.
