Final answer:
To calculate the density of air at STP, you need to determine the molar mass of air and use the ideal gas law. Air is mainly composed of nitrogen and oxygen. Calculate the molar mass of air using the molar masses of nitrogen and oxygen, then use the ideal gas law to calculate the number of moles of air. Finally, use the density formula to find the density of air at STP.
Step-by-step explanation:
To calculate the density of air at STP (standard temperature and pressure), we need to determine the molar mass of air and the ideal gas law. Air is about 78% nitrogen (N2), 21% oxygen (O2), and 1% other gases. We can calculate the molar mass of air using the molar masses of nitrogen and oxygen. Then, we can use the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.
First, let's find the molar mass of air:
Molar mass of nitrogen (N2) = 28.0134 g/mol
Molar mass of oxygen (O2) = 31.9988 g/mol
Now, we can calculate the molar mass of air:
Molar mass of air = (78/100) * 28.0134 g/mol + (21/100) * 31.9988 g/mol + (1/100) * (molar mass of other gases)
Next, we can use the ideal gas law to calculate the number of moles of air:
n = PV / (RT)
Since we are given that the air is at STP, we can use the known values for pressure (1 atm) and temperature (273 K).
Finally, we can calculate the density using the formula:
Density = (molar mass of air * pressure) / (gas constant * temperature)
Substituting the values into the formula should give you the density of air at STP.