Well, let's take a closer look at your calculation. You're asking about the "V" value, which represents the volume of oxygen needed. According to the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
You correctly converted the given temperature from Celsius to Kelvin and converted the given mass of nitric oxide to moles. However, it seems that you forgot to include the stoichiometric coefficient in your calculation.
In the balanced equation, it states that 4 moles of ammonia react with 5 moles of oxygen to produce 4 moles of nitric oxide. Therefore, the number of moles of oxygen needed would be (1.667 mol nitric oxide) * (5 mol oxygen / 4 mol nitric oxide) = 2.084 moles of oxygen.
Now let's redo the calculation using the correct number of moles:
2.15 atm * V = (2.084 mol) * (0.0821 L·atm/(mol·K)) * (308 K)
Simplifying this equation gives us:
V = (2.084 * 0.0821 * 308) / 2.15
V = 19.68 L
So, it seems like there was a small mistake in your calculation. The correct volume of oxygen needed to produce 50.0 g of nitric oxide at 35 degrees C and 2.15 atm is approximately 19.68 liters.