The 2 liter bottle contains helium. The internal energy of helium is 300 J. Determine the pressure in the vessel.

The internal energy of helium can be calculated by the formula (we take into account that helium is a monoatomic gas):

U = 3/2 * pV, where U is the internal energy of helium (U = 300 J), p is the pressure in the cylinder, V is the volume of the cylinder (V = 2 l = 2 dm3 = 2 * 10-3 m3).

Express and calculate the pressure in the cylinder:

p = U / (3/2 V) = 2U / 3V = 2 * 300 / (3 * 2 * 2 * 10-3) = 100000 Pa = 100 kPa.

Answer: The pressure in the cylinder is 100 kPa.