posted by Michelle .
How many moles of hydrogen are needed to triple the volume occupied by 0.25 mol of hydrogen, assuming no changes in pressure or temperature
You can figure this yourself two ways.
1. intuitive. You figure 3 times 0.25 should occupy 3 times as much.
2. with math. PV = nRT and solve for
V = nRT/P. If R, T, and P are constant, then
V = n*some k.
So if we want V to be 3x, we need to have 3n*k.