CHEMICAL THERMODYNAMICS! CLASS 11 A sample of gas present in a cylinde

1.	CHEMICAL THERMODYNAMICS! CLASS 11 A sample of gas present in a cylinder fitted with a frictionless piston expands against a constant pressure of 1atm from a volume of 2L to 12L. During the process it absorbs 600J of heat from the surroundings. Calculate the change in internal energy of the system.
Answer» Given: q= 600 J Initial volume= 2L Final Volume = 12L Pressure = 1atm ━━━━━━━━━━━━━━━━━━━━━━ Solution: Change in volume: = Vfinal- Vinitial =12L - 2L = 10L ━━━━━━━━━━━━━━━ We know, w= -P × Change in volume =>w = -1 ×10 L-atm => w = -10 L- atm Now 1 L-atm =101.3 J w = -10× 101.3J => w = -1013 J ━━━━━━━━━━━━━━━━━ According to first law of THERMODYNAMICS, Change in energy = q+ w => Change in energy = 600 - 1013 J => Change in energy = $\bold{\red{-413 J}}$

CHEMICAL THERMODYNAMICS! CLASS 11 A sample of gas present in a cylinder fitted with a frictionless piston expands against a constant pressure of 1atm from a volume of 2L to 12L. During the process it absorbs 600J of heat from the surroundings. Calculate the change in internal energy of the system.

Answer»

━━━━━━━━━━━━━━━━━━━━━━

Change in volume:

= Vfinal- Vinitial

=12L - 2L

= 10L

━━━━━━━━━━━━━━━

We know,

=>w = -1 ×10 L-atm

=> w = -10 L- atm

Now 1 L-atm =101.3 J

w = -10× 101.3J

━━━━━━━━━━━━━━━━━

According to first law of THERMODYNAMICS,

=> Change in energy = 600 - 1013 J

=> Change in energy = $\bold{\red{-413 J}}$