What is the vapor pressure of ethanol at 13 C?
To find the vapor pressure of ethanol at 13°C, we can refer to a vapor pressure chart or use the equation given by Antoine equation:
log(P) = A - (B / (T + C))
Where:
P is the vapor pressure in mmHg
T is the temperature in °C
The values of A, B, and C for ethanol are as follows:
A = 8.20417
B = 1642.89
C = 225.69
Let's substitute the given temperature into the equation:
log(P) = 8.20417 - (1642.89 / (13 + 225.69))
Calculating the right-hand side of the equation:
log(P) = 8.20417 - (1642.89 / 238.69)
log(P) = 8.20417 - 6.8768
log(P) = 1.32737
Now, we can solve for P by taking the inverse log:
P = 10^1.32737
P ≈ 21.77 mmHg
Therefore, the vapor pressure of ethanol at 13°C is approximately 21.77 mmHg.
To find the vapor pressure of ethanol at 13°C, you can use available data or reference tables. The vapor pressure of a substance is often determined through experimental measurements at various temperatures and is usually documented in reference books or databases.
One commonly used source is the Antoine equation, which relates the vapor pressure of a substance to its temperature. The equation is typically in the form:
log(P) = A - (B / (T + C))
Where P is the vapor pressure, T is the temperature in Kelvin, and A, B, and C are substance-specific constants.
For ethanol, the Antoine equation constants are typically given as:
A = 8.20417
B = 1642.89
C = -54.424
To find the vapor pressure of ethanol at 13°C (which is 286.15 Kelvin), you can substitute the values into the equation:
log(P) = 8.20417 - (1642.89 / (286.15 - 54.424))
By solving this equation, you will get the logarithm of the vapor pressure. To find the actual vapor pressure, you would then take the antilogarithm (10x) of the result.
However, if you have access to a reliable reference book or online database, it is often easier and more accurate to simply look up the vapor pressure of ethanol at 13°C.
Ethanol has a heat of vaporization of 38.56 kJ/mol and a normal boiling point of 78.4 C.
I assume you have a table but if not, here is a site that allows one to calculate vapor pressure at the desired T.
http://www.s-ohe.com/Ethanol_cal.html