Hydrocarbones Temperature Vapor Pressures

Overview

Engineering reference data for Hydrocarbones Temperature Vapor Pressures in chemistry.

Key Formulas

Ideal Gas Law

$PV = nRT$

Pressure × Volume = moles × gas constant × temperature.

Molarity

$M = \frac{n}{V}$

Moles of solute per liter of solution.

pH

$pH = -\log_{10}[H^+]$

Measure of acidity.

Variables

Symbol	Description	Unit
$P$	Pressure	Pa
$V$	Volume	m³
$n$	Moles	mol
$R$	Gas constant	8.314 J/(mol·K)

Vapor Pressure Data for Common Hydrocarbons

The following table provides representative vapor pressure data for propane, n-butane, n-pentane, and n-heptane at various temperatures. This data is crucial for process design involving separation, storage, and pipeline transport of these compounds.

Hydrocarbon Physical Properties

Understanding vapor pressure requires context about the compounds' basic properties. The following table summarizes key data for the hydrocarbons discussed.

Key Relationships and Equations

The vapor pressure of a pure component is a strong function of temperature. This relationship is quantitatively described by the Clausius-Clapeyron equation, which can be integrated to yield:

$\ln\left(\frac{P_2}{P_1}\right) = \frac{\Delta H_{vap}}{R} \left(\frac{1}{T_1} - \frac{1}{T_2}\right)$

Where:

• $P_1, P_2$ are vapor pressures at temperatures $T_1, T_2$ (in Kelvin).
• $\Delta H_{vap}$ is the enthalpy of vaporization (J/mol).
• $R$ is the universal gas constant (8.314 J/mol·K).

For engineering calculations over wider temperature ranges, the Antoine equation is more commonly used due to its empirical accuracy:

$\log_{10}(P) = A - \frac{B}{C + T}$

Where $P$ is in mmHg, $T$ is in °C, and $A, B, C$ are substance-specific constants.

Interactive Charts

References

• Original Source