What pressure would be required to compress 7.75 liters of hydrogen at atmospheric pressure to 5 liters

since PV is constant, you want P such that

7.75 * 1 = 5P

To determine the pressure required to compress 7.75 liters of hydrogen to 5 liters at atmospheric pressure, we can use Boyle's Law, which states that the product of the initial pressure and volume is equal to the product of the final pressure and volume for a given amount of gas, assuming constant temperature.

Boyle's Law equation: P1 * V1 = P2 * V2

Given:
V1 = 7.75 liters (initial volume)
V2 = 5 liters (final volume)
P1 = atmospheric pressure (let's assume it's 1 atmosphere)
P2 = unknown

Substituting the given values into the equation, we have:
1 atmosphere * 7.75 liters = P2 * 5 liters

Simplifying the equation:
7.75 = 5P2

Now, solve for P2 by dividing both sides of the equation by 5:
P2 = 7.75 / 5

Calculating the value:
P2 = 1.55 atmospheres

Therefore, to compress 7.75 liters of hydrogen at atmospheric pressure to 5 liters, a pressure of 1.55 atmospheres would be required.