How is the pressure of a gas related to its concentration of particles? a) pressure will expand a gas, enlarging its volume and reducing its density and concentration of particles. b) pressure will magnify a gas, developing its volume and multiplying its density and concentration of particles. c) pressure will compress a gas, reducing its volume and giving it a greater density and concentration of particles. d) pressure will accelerate a gas, extending its volume and allowing a smaller density and concentration of particles.

C) Pressure will compress a gas, reducing its volume and giving it a greater density and concentration of particles. Let's look at the available choices and determine why or why not they're correct. A) Pressure will expand a gas, enlarging its volume and reducing its density and concentration of particles. * What? So increasing the pressure on a gas will make it take up a larger volume? That definitely doesn't match the world I live in. I hope that's true for you as well. Wrong choice. B) Pressure will magnify a gas, developing its volume and multiplying its density and concentration of particles. * Lots of interesting sounding words, but they're mostly used in a nonsense fashion. Useful if you're easily fooled by technobabble, but it's another wrong answer. C) Pressure will compress a gas, reducing its volume and giving it a greater density and concentration of particles. * OK. Increasing the pressure will compress a gas. So it has a smaller volume. And since it still has the same mass, the density will become greater. And the particles closer together. Everything here matches reality. Good choice. D) Pressure will accelerate a gas, extending its volume and allowing a smaller density and concentration of particles. * Most technobabble. Why would the gas be accelerated? No reason that I know of. Wrong choice.

The rocks expand when there hot/warm  and contract when they are cold.