Question

The temperature, T, of a gas is jointly proportional to the pressure P of the gas and the volume V occupied by the gas. Use C as your proportionality constant. (a) Express the temperature in terms of the pressure and the volume.

Answer 1

Answer:

T=C*P*V

Explanation:

It is said that a variable - let's call 'y' -, is proportional to another - let's call it 'x' - if x and y are multiplicatively connected to a constant 'C'. It means that their product (x*y) can be always equaled to the constant 'C' or their division ($\frac{x}{y}$) can be always equaled to 'C'. The first case is the case of the inverse proportionality: It is said that x and y are inversely proportional if

$x*y=C$

The second case is the case of the direct proportionality: It is said that x and y are directly proportional if

$\frac{x}{y} =C$ : x is directly proportional to y.

or

$\frac{y}{x} =C$ : y is directly proportional to x.

Always that any text does not specify about directly or inversely proportionality, it is assumed to mean directly automatically.

For our case, we are said that the temperature T is proportional to the pressure P and the volume V (we assume that it means directly); it is a double proportionality but follows the same rules:

If T were just proportional to P, we would have:

$\frac{T}{P} =C$

If T were just proportional to V, we would have:

$\frac{T}{V} =C$

As T is proportional to both P and V, the right equation is:

$\frac{T}{P*V}=C$

In order to isolate the temperature, let's multiply (P*V) at each side of the equation:

$\frac{T}{P*V}*(P*V)=C*(P*V)\\T=C*P*V$