hi, i think this prob has to do what you did the last time
but how does pressure play appart in this chapter??
What pressure would have to be applied to steam at 325°C to condense the steam to liquid water (ÄH vap = 40.7 kJ/mol)?
http://www.lsbu.ac.uk/water/phase.html
Use the Clausius-Clapeyron Equation to calculate the vapor pressure at 325°C. That is the pressure that must be applied to condense the steam at 325°C.
Ln(P2/P1) = (∆H/R)[(T2-T1)/T2T1]
P1 = 1 atm
∆H = 40700J
R = 8.3145 J/°K.mol
T2 = (325+273) = 598°K
T1 = (100+273) = 373°K
P2 = (unknown)
[NOTE: The pressure needed is quite high]
i solved for lnx=4,852,725
whats next? and i relaly cant put it into the calc. it says (overflow)
Hi! To determine the pressure required to condense steam at a specific temperature, you would use the Clausius-Clapeyron equation. This equation relates the vapor pressure of a substance to its temperature and the enthalpy of vaporization.
The Clausius-Clapeyron equation is given by:
ln(P2/P1) = (-ΔHvap/R) * (1/T2 - 1/T1)
Where:
- P1 and P2 are the initial and final pressures (in this case, vapor pressure and the pressure required to condense the steam).
- ΔHvap is the enthalpy of vaporization (40.7 kJ/mol in this case).
- R is the ideal gas constant (8.314 J/(mol·K)).
- T1 and T2 are the initial and final temperatures (in this case, the boiling point of water and 325°C).
To solve for the pressure required to condense the steam, follow these steps:
1. Convert the given temperature from Celsius to Kelvin by adding 273.15. So, 325°C = 598.15 K.
2. The initial pressure (P1) would be the vapor pressure of steam at 100°C (the boiling point of water). You can find the vapor pressure of steam at different temperatures in tables or use an online resource. At 100°C, the vapor pressure of water is approximately 1.01325 bar.
3. Plug in all the known values into the Clausius-Clapeyron equation and solve for P2.
ln(P2/1.01325) = (-40.7 * 10^3 J/mol) / (8.314 J/(mol·K)) * (1/598.15 K - 1/373.15 K)
4. Solve for P2 by taking the exponential of both sides of the equation: P2 = 1.01325 * e^((-40.7 * 10^3)/(8.314 * (1/598.15 - 1/373.15)))
By following these steps and plugging in the respective values, you can find the pressure required to condense the steam at 325°C.