# Question #06a40

Oct 1, 2017

Impossible to determine.

#### Explanation:

We will assume an ideal gas.

Ideal gas law:

$\frac{P V}{T} = \text{constant}$

$\implies \textcolor{b l u e}{\frac{{P}_{i} {V}_{i}}{T} _ i = \frac{{P}_{f} {V}_{f}}{T} _ f}$

$1 \to 2$

To get from point 1 to point 2, we see that the pressure of the gas decreases as the volume of the gas increases, i.e. the pressure of the gas decreases while the gas expands

• There are no isotherms in this graph, so we know that T is not constant, i.e. T must be increasing or decreasing. We are also told this. This tells us that during this expansion, all variables are subject to change.

• Because we are not given any values for the pressure and volume nor any specific information about how quickly they change, it is hard to say what exactly happens to the temperature:

• If the pressure is dropping at a faster rate than the volume of the gas increases, the temperature must increase to make up for this

• If the pressure is dropping at a slower rate than the volume of the gas increases, the temperature must decrease to make up for this

I would say it is not choice 3, as this implies that the rate at which the pressure and volume change is not constant; the graph does show a constant rate of change.

$\therefore$Choice 1 is correct if the pressure drops at a faster rate than the volume increases

$\therefore$ Choice 2 is correct if the pressure drops at a slower rate than the volume increases