The vapor pressure of dichloromethane, , at 0 is 134 . The normal boiling point of dichloromethane is 40. . Calculate its molar heat of vaporization
correction= The vapor pressure of dichloromethane,ch2, cl2 at 0 degrees celcius is 134mmhg . The normal boiling point of dichloromethane is 40.degrees celcius. Calculate its molar heat of vaporization
Use the Clausius-Clapeyron equation.
Also, note the correct spelling of celsius.
375 Torr
To calculate the molar heat of vaporization for dichloromethane, we can utilize the Clausius-Clapeyron equation. This equation relates the vapor pressure of a substance at different temperatures to its molar heat of vaporization.
The Clausius-Clapeyron equation is given as:
ln(P2/P1) = -ΔHvap/R * (1/T2 - 1/T1)
Where:
P1 is the initial vapor pressure (atmospheres),
P2 is the final vapor pressure (atmospheres),
ΔHvap is the molar heat of vaporization in J/mol,
R is the ideal gas constant (8.314 J/(mol·K)),
T1 is the initial temperature (Kelvin),
T2 is the final temperature (Kelvin).
In this case, we have:
P1 = 134 torr (which we'll convert to atmospheres),
T1 = 0 °C (which we'll convert to Kelvin),
T2 = 40 °C (which we'll convert to Kelvin).
First, let's convert the temperatures from Celsius to Kelvin:
T1 = 0 + 273.15 = 273.15 K
T2 = 40 + 273.15 = 313.15 K
Next, let's convert the initial vapor pressure from torr to atmospheres:
P1 = 134 torr / 760 torr/atm ≈ 0.176 atm
Now we can plug the values into the Clausius-Clapeyron equation and solve for ΔHvap:
ln(P2/P1) = -ΔHvap/R * (1/T2 - 1/T1)
ln(P2/0.176) = -ΔHvap/(8.314) * (1/313.15 - 1/273.15)
Now, let's rearrange the equation to solve for ΔHvap:
ΔHvap = -(ln(P2/0.176) * 8.314 * (1/313.15 - 1/273.15))
To find the value of P2, we need additional information. We can use the fact that at the normal boiling point, the vapor pressure is equal to atmospheric pressure (1 atm). So, we'll use P2 = 1 atm:
ΔHvap = -(ln(1/0.176) * 8.314 * (1/313.15 - 1/273.15))
Calculating this expression will give us the molar heat of vaporization of dichloromethane (CH2Cl2).