1. Understand STP
STP stands for Standard Temperature and Pressure. It's defined as:
* Temperature: 0°C (273.15 K)
* Pressure: 1 atm (101.325 kPa)
2. Ideal Gas Law
The ideal gas law relates pressure (P), volume (V), temperature (T), and the number of moles (n) of a gas:
PV = nRT
Where:
* R is the ideal gas constant (0.0821 L·atm/mol·K)
3. Density Calculation
Density (ρ) is mass (m) per unit volume (V):
ρ = m/V
To find the density of SF₆ at STP, we can use the ideal gas law and the following steps:
* Molar Mass: Find the molar mass of SF₆ (32.06 g/mol for sulfur + 6 * 18.998 g/mol for fluorine = 146.06 g/mol)
* Solve for Volume: Rearrange the ideal gas law to solve for volume: V = nRT/P
* Substitute and Calculate: Since we want density at STP, we can assume 1 mole of SF₆ (n = 1 mol) and substitute the values:
* V = (1 mol * 0.0821 L·atm/mol·K * 273.15 K) / 1 atm = 22.4 L
* Calculate Density: Divide the molar mass by the volume:
* ρ = 146.06 g/mol / 22.4 L/mol = 6.52 g/L
Therefore, the density of sulfur hexafluoride (SF₆) at STP is approximately 6.52 g/L.
