Final answer:
Using the Ideal Gas Law, the pressure in a 20.0 L cylinder filled with 45.4 g of oxygen gas at a temperature of 315 K is found to be 3.80 atm, which corresponds to option D.
Step-by-step explanation:
To determine the pressure in a 20.0 L cylinder filled with 45.4 g of oxygen gas at a given temperature, you can use the Ideal Gas Law, PV = nRT. The first step is to find the number of moles (n) of oxygen. One mole of O₂ weighs 32.00 g, so the number of moles of oxygen is:
n = 45.4 g O₂ / 32.00 g/mol = 1.41875 mol O₂
Next, apply the Ideal Gas Law using R, the universal gas constant, as 0.0821 L·atm·K⁻¹·mol⁻¹. We integrate the given temperature of 315 K and volume of 20.0 L to find the pressure (P):
P = nRT/V
P = (1.41875 mol) × (0.0821 L·atm·K⁻¹·mol⁻¹) × (315 K) / (20.0 L)
P = 1.84825 atm·K·L/mol·K / 20.0 L
P = 3.80 atm
Therefore, the pressure in the cylinder is 3.80 atm, which corresponds to option D.