This boiling point calculator is a valuable tool in chemistry designed to compute the temperature at which a liquid transitions to a gas at a specific pressure.
This calculator takes into account various factors that influence boiling point, such as atmospheric pressure, altitude, and the properties of the substance in question.
Boiling Point Calculator
| Substance | Pressure (atm) | Calculated Boiling Point (°C) |
|---|---|---|
| Water | 1.0 | 100.0 |
| Water | 0.9 | 96.6 |
| Water | 0.8 | 92.5 |
| Water | 0.7 | 88.3 |
| Water | 0.5 | 81.3 |
| Ethanol | 1.0 | 78.4 |
| Ethanol | 1.2 | 82.5 |
| Ethanol | 1.5 | 89.7 |
| Ethanol | 0.8 | 70.5 |
| Acetone | 1.0 | 56.1 |
| Acetone | 0.9 | 54.2 |
| Acetone | 0.8 | 49.2 |
| Acetone | 0.6 | 43.7 |
| Hexane | 1.0 | 68.7 |
| Hexane | 0.9 | 66.5 |
| Hexane | 0.8 | 64.3 |
| Benzene | 1.0 | 80.1 |
| Benzene | 0.9 | 77.6 |
| Benzene | 0.8 | 75.2 |
Boiling Point Formula
The boiling point formula is:
ΔTb = Kb * m * iWhere:
- ΔTb is the change in boiling point
- Kb is the molal boiling point elevation constant
- m is the molality of the solution
- i is the van ‘t Hoff factor
What is Boiling Point?
The boiling point of a substance is the temperature at which its vapor pressure equals the surrounding atmospheric pressure.
At this point, the liquid begins to vaporize and form bubbles throughout its volume, not just at the surface.
Let’s consider ethanol boiling point at standard atmospheric pressure (1 atm) is approximately 78.37°C (173.07°F). This means that when ethanol reaches this temperature, it will begin to boil and transform into a gas.
How do you calculate boiling point?
Here’s a step-by-step approach:
Determine the atmospheric pressure: This is crucial as it directly affects the boiling point.
Identify the substance: Each substance has unique properties that influence its boiling point.
Use the Clausius-Clapeyron equation for a more precise calculation:
ln(P2/P1) = (ΔHvap/R) * (1/T1 - 1/T2) Where:
- P1 and P2 are pressures
- T1 and T2 are temperatures
- ΔHvap is the heat of vaporization
- R is the gas constant
To calculate the boiling point of water at 0.9 atm, we would use this equation with known values for water at 1 atm and 100°C, then solve for T2.
What is the formula for boiling point correction?
The formula is:
Corrected Boiling Point = Observed Boiling Point + 0.00012(760 - P)(273 + t)Where:
- P is the observed atmospheric pressure in mm Hg
- t is the observed boiling point in °C
If water boils at 98°C when the barometric pressure is 740 mm Hg, we can use this formula to correct the boiling point to standard conditions.
The boiling point correction formula is used to adjust observed boiling points to account for variations in atmospheric pressure.
How to calculate boiling point under vacuum?
The Antoine equation is commonly used for this purpose:
log10(P) = A - (B / (C + T))Where:
- P is the vapor pressure
- T is the temperature
- A, B, and C are substance-specific constants
To find the boiling point under vacuum, you would:
- Determine the vacuum pressure.
- Use the Antoine equation with known constants for your substance.
- Solve for T to find the boiling point at that pressure.
For example, to find the boiling point of acetone at 0.5 atm, you would use its specific Antoine constants and solve for T.
Sources / References
- NIST Chemistry WebBook
- Journal of Chemical & Engineering Data
- International Union of Pure and Applied Chemistry (IUPAC)
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