# Heating an Ideal Gas: Why Burning Fuel is Equivalent to Reversible Heating

• Katie1990
In summary, an ideal gas is a theoretical gas that follows the kinetic theory of gases and assumes no intermolecular forces and negligible particle volume. Burning fuel heats an ideal gas by releasing energy in the form of heat, increasing the gas particles' temperature and causing them to move faster. Reversible heating in an ideal gas is achieved by adding and removing heat at the same rate, resulting in no net change in temperature or pressure. Burning fuel is considered equivalent to reversible heating in an ideal gas because the added heat energy is removed at the same rate, while irreversible heating occurs when heat is added and removed at different rates, resulting in a net change in temperature and pressure.
Katie1990

## Homework Statement

I'm struggling to explain why for an ideal gas at constant pressure heating by burning fuel is equivalent to reversible heating. I know that all forms of work on a ideal gas are eqivalent but don't know why.

## The Attempt at a Solution

I wouldn't call the two cases equivalent. In what ways of equivalency do you mean?

The question asks me to explain why burning a fuel that is clearly not reversible is the same as if heat was supplied reversibly.

## 1. What is an ideal gas?

An ideal gas is a theoretical gas that follows the kinetic theory of gases, meaning it has no intermolecular forces and the gas particles are in constant, random motion. It also assumes that the volume of the gas particles is negligible compared to the total volume of the gas.

## 2. How does burning fuel heat an ideal gas?

Burning fuel releases energy in the form of heat. This heat energy is transferred to the surrounding air, increasing the temperature of the gas particles and causing them to move faster. This increase in kinetic energy is equivalent to reversible heating in an ideal gas.

## 3. What is reversible heating?

Reversible heating is a process where heat is added to a system and then removed in a way that the system returns to its original state. In an ideal gas, reversible heating is achieved by adding heat and then removing it at the same rate, resulting in no net change in temperature or pressure.

## 4. Why is burning fuel considered equivalent to reversible heating in an ideal gas?

Burning fuel releases heat energy, which can be added to an ideal gas. This added heat energy increases the gas particles' kinetic energy, causing their temperature and pressure to increase. In a reversible heating process, the heat energy is removed at the same rate, resulting in the gas returning to its original state.

## 5. How is burning fuel different from irreversible heating of an ideal gas?

Irreversible heating of an ideal gas occurs when heat is added to the system and then removed at different rates, resulting in a net change in temperature and pressure. Burning fuel, on the other hand, is considered equivalent to reversible heating because the added heat energy is removed at the same rate, resulting in no net change in the gas's temperature or pressure.

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