# Thermodynamics- 1st Law Question

• FordRanger4x4
In summary, the conversation discusses a problem involving a gas enclosed in a container with a piston and the increase in internal energy of the gas as it is heated. The pressure of the gas is constant and the heat input and displacement are given. The equation used is the first law and the change in volume is needed to solve for work.
FordRanger4x4

## Homework Statement

A gas is enclosed in a container fitted with a piston of cross-sectional area 0.1 m2. The pressure of the gas is maintained constant at 8 kPa, while the gas is heated slowly and the piston moves outward a distance of 40 mm. Heat input to the gas during this process is 42 J. What is the increase in internal energy of the gas?

## Homework Equations

I know that the first law needs to be used here, and i am neglecting Kinetic and Potential Energy

Q-W=(delta)U

## The Attempt at a Solution

Im having trouble solving for work, this is what i have so far.

42J-8KPa(V2-V1)=(delta) U

any help would be great, thanks

FordRanger

You don't really need to know V1 and V2. You only need the change in volume. Since you have the cross sectional area of the cylinder and the displacement, you can find delta-V and complete your problem.

Thanks, i ended up figuring it out pretty soon after posting.

## What is the 1st Law of Thermodynamics?

The 1st Law of Thermodynamics states that energy cannot be created or destroyed, but it can be transferred from one form to another or converted into different forms. This is also known as the principle of conservation of energy.

## What is the difference between heat and temperature?

Heat is the transfer of thermal energy between two objects or systems, while temperature is a measure of the average kinetic energy of the particles within a system. In other words, heat is the energy that is being transferred, while temperature is a measure of the intensity of that energy.

## What is an adiabatic process?

An adiabatic process is a thermodynamic process in which no heat is exchanged between a system and its surroundings. This means that the system is insulated and does not allow for the transfer of heat energy.

## What is the difference between an open and closed system?

An open system is one in which both energy and matter can be exchanged with its surroundings, while a closed system only allows for the exchange of energy. In other words, an open system can both gain and lose mass, while a closed system cannot.

## What is entropy?

Entropy is a measure of the disorder or randomness in a system. It is also known as the second law of thermodynamics, which states that the total entropy of an isolated system will never decrease over time.

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