1. What is the Density Equation?

The density equation calculates the density of a gas from its molecular weight, pressure, temperature, and the gas constant. It's derived from the ideal gas law and provides the mass per unit volume of a substance.

2. How Does the Calculator Work?

The calculator uses the density equation:

Where:

• \( \rho \) — Density (kg/m³)
• \( M \) — Molecular weight (g/mol)
• \( P \) — Pressure (Pa)
• \( R \) — Gas constant (8.314 J/mol·K)
• \( T \) — Temperature (K)

Explanation: The equation relates the density of a gas to its molecular weight and the state conditions (pressure and temperature).

3. Importance of Density Calculation

Details: Density calculations are essential in chemical engineering, thermodynamics, and fluid dynamics for designing processes, equipment, and understanding material properties.

4. Using the Calculator

Tips: Enter molecular weight in g/mol, pressure in Pascals, gas constant (default is 8.314 J/mol·K), and temperature in Kelvin. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal gas constant?
A: The gas constant (R) is 8.314 J/mol·K in SI units. It relates energy scale to temperature scale for a mole of particles.

Q2: Can this be used for liquids?
A: No, this equation is specifically for ideal gases. Liquids have different density relationships.

Q3: What are typical density values for gases?
A: At STP (273.15K, 101325 Pa), air has density ~1.225 kg/m³, while hydrogen is ~0.08988 kg/m³.

Q4: How does temperature affect density?
A: Density decreases with increasing temperature at constant pressure (inverse relationship).

Q5: What are the limitations of this equation?
A: It assumes ideal gas behavior. For real gases at high pressures or low temperatures, more complex equations are needed.