Answer :

To determine the pressure of an ideal gas under specific conditions, we can use the Ideal Gas Law, which is given by the equation [tex]\( PV = nRT \)[/tex]. Here’s a detailed, step-by-step solution:

1. Identify the given values:
- Number of moles ([tex]\( n \)[/tex]) = 33.5 mol
- Volume ([tex]\( V \)[/tex]) = 35.5 L
- Temperature in Celsius ([tex]\( T_{C} \)[/tex]) = 85.00°C

2. Convert the temperature from Celsius to Kelvin:
The Ideal Gas Law requires the temperature in Kelvin. To convert Celsius to Kelvin, use the relationship:
[tex]\[ T_{K} = T_{C} + 273.15 \][/tex]
So,
[tex]\[ T_{K} = 85.00 + 273.15 = 358.15 \text{ K} \][/tex]

3. Use the Ideal Gas Constant [tex]\( R \)[/tex]:
The value of the ideal gas constant [tex]\( R \)[/tex] in the correct units (L.atm/(mol.K)) is:
[tex]\[ R = 0.0821 \text{ L.atm/(mol.K)} \][/tex]

4. Substitute all the known values into the Ideal Gas Law equation and solve for pressure ([tex]\( P \)[/tex]):
[tex]\[ PV = nRT \][/tex]
Rearrange to solve for [tex]\( P \)[/tex]:
[tex]\[ P = \frac{nRT}{V} \][/tex]
Plug in the values:
[tex]\[ P = \frac{(33.5 \text{ mol}) \times (0.0821 \text{ L.atm/(mol.K)}) \times (358.15 \text{ K})}{35.5 \text{ L}} \][/tex]

5. Calculate the pressure:
[tex]\[ P = \frac{33.5 \times 0.0821 \times 358.15}{35.5} \][/tex]
Simplifying this:
[tex]\[ P \approx 27.74754514084507 \text{ atm} \][/tex]

Hence, the pressure of the gas under the given conditions is approximately [tex]\( 27.75 \)[/tex] atm.