I need help with answering this question.
What is the absolute entropy of 1.9 mol of gaseous ammonia at 2.8 bar and 298 K?
Thank you
To find the absolute entropy of 1.9 mol of gaseous ammonia at 2.8 bar and 298 K, we can use the standard molar entropy data. The absolute entropy is usually given as S° (pronounced "S naught").
1. Start by looking up the standard molar entropy of ammonia (NH3) in a reference source, such as a chemistry textbook or an online database.
For ammonia (NH3), the standard entropy is typically given as 192.66 J/(mol·K).
2. Note that the standard molar entropy is given under standard conditions, which are defined as 1 bar of pressure and usually 298 K.
In this case, the given conditions are at 2.8 bar and 298 K. So, we will need to adjust the standard entropy value to account for the different pressure.
3. Calculate the change in entropy (∆S) using the equation:
∆S = R ln (P2 / P1)
Where R is the ideal gas constant (8.314 J/(mol·K)), P1 is the standard pressure (1 bar), and P2 is the given pressure (2.8 bar).
∆S = (8.314 J/(mol·K)) × ln(2.8 bar / 1 bar)
4. Calculate the absolute entropy (S) using the equation:
S = S° + ∆S
Where S° is the standard molar entropy and ∆S is the change in entropy calculated in the previous step.
S = 192.66 J/(mol·K) + ∆S
5. Substitute the value of ∆S into the equation and calculate the absolute entropy (S).
S = 192.66 J/(mol·K) + ∆S
After performing the calculations, you should obtain the absolute entropy of 1.9 mol of gaseous ammonia at the given conditions.
Please note that the calculation provided here assumes ideal gas behavior and that the standard molar entropy value is valid for the given compound under the specified conditions.