In an automobile engine, a piston will compress fuel vapors in a chamber before a spark plug ignites it causing combustion. as the gas pressure builds up, the volume will be at a and the density will be at a

a) maximum; maximum
b) maximum; minimum
c) minimum; minimum
d) minimum; maximum

B) maximum; minimum

Explanation:

Pressure is the force exerted by a gas, a liquid or a solid on a surface (or area) .

On the other hand, density is defined as the relation between the mass and the volume :

So, when the volume increases, the density decreases and when the volume decreases, the density increases.

Now, in the case of an automobile engine when the gas pressure builds up (increases) the volume of the expaned gas increases, as well. Since there is an inverse relation between density and volume, the density will decrease.

multiply 2kg by latent heat of vap