Calculate Normal Boiling Point of Ethyl Alcohol

In summary, To find the normal boiling point of ethyl alcohol in Celsius, we use the equation (Delta) Tb = Kb x m, where Kb is provided as 1.22 (Celsius x kg)/mol and m is the molality calculated by dividing the moles of glucose by the mass of ethyl alcohol in kg. After converting 26g of glucose to moles and 285g of ethyl alcohol to kg, we get a molality of 0.491. Plugging this into the equation, we get a change in boiling point of 0.599 Celsius. Subtracting this from the given boiling point of 79.1 Celsius, we get a normal boiling point of 78.5 Celsius
  • #1
Torshi
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Homework Statement


What is the normal boiling point in Celsius of ethyl alcohol if a solution prepared by dissolving 26.0g of glucose C6H12O6 in 285g of ethyl alcohol has a boiling point of 79.1 Celsius? Kb for ethyl alcohol is 1.22( Celsius x kg)/mol .


Homework Equations



26g of glucose Mole conversion.
285 gram ----> kg
Molality, m = mole/kg

Equation = (Delta) Tb= Kb x m
Kb is given. m is what I found.

The Attempt at a Solution


Mole of 26g glucose is 26/180g (molar mass)= .14 moles
285g equals .285k kg
.14 mol/.285 kg = .491 m
---------------------------------------
Kb x m -------------> 1.22 x .491 = .599 Celsius
Delta T: 79.1 celsius - .599 celsius = 79 Celsius

My calculation has a rounding error? I'm close with the answer, idk what I'm doing wrong.
 
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  • #2
Try subtracting 0.599 from 79.1 again.
 

1. What is the normal boiling point of ethyl alcohol?

The normal boiling point of ethyl alcohol (also known as ethanol) is 78.37 degrees Celsius or 173.03 degrees Fahrenheit.

2. How do you calculate the normal boiling point of ethyl alcohol?

The normal boiling point of ethyl alcohol can be calculated using the Clausius-Clapeyron equation, which takes into account the vapor pressure and enthalpy of vaporization of the substance. This equation is often simplified to: ln(P2/P1) = -(ΔHvap/R)(1/T2 - 1/T1), where P1 and T1 are the initial pressure and temperature, P2 and T2 are the final pressure and temperature, ΔHvap is the enthalpy of vaporization, and R is the gas constant.

3. What is the enthalpy of vaporization for ethyl alcohol?

The enthalpy of vaporization for ethyl alcohol is 38.56 kJ/mol, or 9.2 kcal/mol.

4. How does altitude affect the normal boiling point of ethyl alcohol?

As altitude increases, the atmospheric pressure decreases, resulting in a decrease in the normal boiling point of ethyl alcohol. This is because the substance will require less energy to overcome the lower pressure and reach its boiling point.

5. Can the normal boiling point of ethyl alcohol be changed?

The normal boiling point of ethyl alcohol can be changed by altering the atmospheric pressure. For example, at higher altitudes where the atmospheric pressure is lower, the boiling point will also be lower. Additionally, impurities in the substance can also affect the boiling point.

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