A sample of gas with a volume of 2.0 L exerts a pressure of 1.0 atm. If the volume is changed to 1.0 L (at constant temperature), what is the pressure?

a. 0.5 atm
b. 1.0 atm
c. 2.0 atm
d. 4.0 atm

P1V1 = P2V2

To find the pressure when the volume is changed, we can use Boyle's law, which states that the pressure of a gas is inversely proportional to its volume at constant temperature.

Boyle's law can be expressed as:
P1V1 = P2V2

Where:
P1 = initial pressure
V1 = initial volume
P2 = final pressure (what we want to find)
V2 = final volume

In this case, the initial pressure (P1) is 1.0 atm, the initial volume (V1) is 2.0 L, the final volume (V2) is 1.0 L, and we need to find the final pressure (P2).

Using Boyle's law equation, we can rearrange it to solve for P2:
P2 = (P1 * V1) / V2

Substituting the given values, we have:
P2 = (1.0 atm * 2.0 L) / 1.0 L
P2 = 2.0 atm

Therefore, the answer is c. 2.0 atm.