Respuesta :
Answer:
Pv sln = 110.902 torr
Explanation:
- Pv sln = Pv H2O*XH2O + Pvethanol*Xethanol
∴ m sln = 5g H2O + 78g ethanol = 83 g
⇒ X H2O = m H2O/m sln = 5 / 83 = 0.0602
⇒ X ethanol = 78 / 83 = 0.9396
∴ Pv H2O = 47 torr
∴ Pv ethanol = 115 torr
⇒ Pv sln = ((47 torr)*(0.0602)) + ((115 torr)*(0.9396))
⇒ Pv sln = 110.902 torr
Answer:
The vapor pressure of the solution is 105.4 torr
Explanation:
Step 1: Data given
MAss of water = 5.0 grams
Mass of ethanol = 78.0 grams
Temperature = 37 °C = 310 K
Molar mass water = 18.02 g/mol
Molar mass ethanol = 46.07 g/mol
The vapor pressures of ethanol = 115 torr
The vapor pressures of water at this temperature = 47 torr
Step 2: Calculate moles
Moles = mass / molar mass
Moles water = 5.0 grams / 18.02 g/mol
Moles water = 0.277 moles
Moles ethanol = 78.0 grams / 46.07 g/mol
Moles ethanol = 1.693 moles
Step 3: Calculate total moles
Total moles = 0.277 moles + 1.693 moles
Total moles = 1.97 moles
Step 4: Calculate mol fraction
Mol fraction = moles / total moles
Mol fraction H2O = 0.277 moles / 1.97 moles
Mol fraction H2O = 0.141
Mol fraction ethanol = 1.693 moles/1.97 moles
Mol fraction ethanol = 0.859
Step 5: Calculate the vapor pressure of the solution
Vapor pressure solution = pH2O * XH2O + pethanol * Xethanol
⇒with pH2O = the vapor pressure of H2O = 47 torr
⇒with XH2O = the mol fraction of H2O = 0.141
⇒with pEthanol = vapor pressure of ethanol = 115 torr
⇒with Xethanol = mol fraction of ethanol = 0.859
Vapor pressure solution = 47*0.141 + 115*0.859
Vapor pressure solution = 105.4 torr
The vapor pressure of the solution is 105.4 torr
