What is the final pressure assuming that temperature and the number of moles are constant?

Question

A chamber initially at 0.985 atm and 22.4 L of He undergoes a change in pressure such that the final volume is 

50.1 L. What is the final pressure assuming that temperature and the number of moles are constant?

answer in atm

Answer 1

You need to use Boyle's Law

P_iV_i = P_fV_f

where

P_i = initial pressure = 0.986 Atm

V_i = initial volume = 22.4 L

P_f = final pressure = Unknown

V_f = final volume = 50.1 L

0.985 Atm. X 22.4 L = x X 50.1L

0.985 Atm. X 22.4 L / 50.1 L = x

0.440 Atm =x =V_i

Answer 2

You can solve this problem using Boyle's Law, which is written as P₁V₁=P₂V₂, where P₂ is what you are solving for in this case. When you substitute the numbers into the formula, it looks like this:

0.985 atm * 22.4 L He=P₂ * 50.1 L He.

The left side works out to 22.064 atm * L He. So then you divide both sides by 50.1 L He to get P₂ alone and cancel the L He and what you are left with is that P₂=0.440 atm.

Hope all of that made sense!