Determine the density of CO2 gas at STP.
You should remember that 1 mole of a gas at STP occupies 22.4L.(and 1 mole CO2 has a mass of 44 g). density = m/v
To determine the density of CO2 gas at STP (Standard Temperature and Pressure), we need to know the molar mass of CO2 and the values of STP.
1. Molar Mass of CO2:
The molar mass of CO2 can be calculated by adding up the atomic masses of carbon (C) and two oxygen atoms (O). The atomic masses can be found on the periodic table.
Carbon (C) atomic mass: 12.01 amu
Oxygen (O) atomic mass: 16.00 amu
Molar mass of CO2 = (12.01 amu) + (16.00 amu) + (16.00 amu) = 44.01 amu/mol
2. STP Conditions:
Standard Temperature and Pressure (STP) refer to a temperature of 273.15 Kelvin (0 degrees Celsius or 32 degrees Fahrenheit) and a pressure of 1 atmosphere (atm) or 101.3 kilopascals (kPa).
3. Ideal Gas Law:
The density (d) of a gas can be calculated using the Ideal Gas Law:
PV = nRT
Where:
P = pressure (in atm or kPa)
V = volume (in liters)
n = number of moles
R = ideal gas constant (0.0821 L.atm/(mol.K) or 8.314 J/(mol.K))
T = temperature (in Kelvin)
At STP, the volume and number of moles are fixed values. Therefore, we can simplify the equation as follows:
PV = nRT
n/V = P/RT
Thus, density (d) can be calculated as:
d = m/V = (molar mass x n)/V = (molar mass x P)/(R x T)
4. Calculating Density:
Using the values for molar mass (44.01 amu/mol), pressure (1 atm or 101.3 kPa), ideal gas constant (0.0821 L.atm/(mol.K) or 8.314 J/(mol.K)), and temperature (273.15 K), we can calculate the density.
d = (44.01 amu/mol x 1 atm)/(0.0821 L.atm/(mol.K) x 273.15 K)
Simplifying and converting units:
d = (44.01 g/mol x 101.3 kPa)/(8.314 J/(mol.K) x 273.15 K)
d = 1.98 g/L (approximately)
Therefore, the density of CO2 gas at STP is approximately 1.98 g/L.