Question

A system is provided 50 J of heat and work done on the system is 10 J. Example What is the change in internal energy?​

Answer 1

11th/Chemistry

Thermodynamics

Answer :

Heat supplied = +50J

Work done on the system = +10J

We have to find change in internal energy of system$.$

⧪ The first law of thermodynamics:

• ∆U = q + W

∆U denotes change in internal energy

q denotes amount of heat

W denotes work done

Substituting given values, we get

➙ ∆U = q + W

➙ ∆U = 50 + 10

➙ ∆U = 60J

Additional Information :

• Internal energy (U) is the total energy within a system. It is the sum of all types of energies (chemical, electrical, mechanical or any other type) of the system and is a state function.
• Thermodynamic process can be isothermal (at constant temperature), adiabatic (completely insulated), isobaric (at constant pressure), isochoric (at constant volume), cyclic, reversible or irreversible.

Cheers!

Answer 2

Given :-

Heat supplied = +50J

Work done on the system = +10J

To find :-

change in internal energy of system

Solution :-

using first law of thermodynamics .i.e.,

$\Large\star$"The net energy change in a closed system is equal to heat absorbed plus the work done by the system"

Mathematically,

∆U = q + W

here,

• ∆U = change in internal energy
• q = amount of heat
• W = work done

According to the question,

➠ ∆U = q + W

➠ ∆U = 50 + 10

➠ ∆U = 60J

Thus, the change in internal energy of system is 60J.

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|| Note :- For absorption of heat'q' is +ve and for release 'q' is -ve ||