What is the final pressure when 100.0mL of a gas at 5.00 atm is compressed to 25.0mL at constant temperature?
(help! timed Test)
A.) 1.25 atm
B.) 500 atm
C.) 10.0 atm
D.) 20.0 atm

D) 20.0 atm

Explanation:

To solve this problem, we can apply Boyle's law, which states that:

"For a constant mass of an ideal gas kept at constant temperature, the pressure of the gas is inversely proportional to the volume of the gas".

Mathematically:

where

p is the gas pressure

V is the volume of the gas

The equation can also be rewritten as

where in this problem:

is the initial pressure of the gas

is the initial volume of the gas

is the final volume of the gas

Solving for p2, we find the final pressure of the gas:

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i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)