Final answer:
The volume occupied by 3.5 mol of oxygen gas at a pressure of 768 mm Hg and a temperature of 25°C is approximately 84.19 liters, calculated using the Ideal Gas Law.
Step-by-step explanation:
To find the volume occupied by 3.5 mol of oxygen gas at a pressure of 768 mm Hg and a temperature of 25°C, we can use the Ideal Gas Law, which is PV = nRT.
First, we need to convert the given pressure from mm Hg to atm, since the gas constant R is typically given in units of L atm/(mol K).
1 atm = 760 mm Hg
So, P (in atm) = 768 mm Hg × (1 atm / 760 mm Hg) = 1.0105 atm
Next, convert the temperature from °C to Kelvin:
T (in K) = 25°C + 273.15 = 298.15 K
The gas constant R = 0.0821 L atm/(mol K).
Now, we can rearrange the ideal gas equation to solve for V:
V = (nRT) / P
V = (3.5 mol × 0.0821 L atm/(mol K) × 298.15 K) / 1.0105 atm
V = 85.1085 L / 1.0105 atm
V = 84.19 L
The volume occupied by 3.5 mol of oxygen gas under the given conditions is approximately 84.19 liters.