The density of nitrogen gas (N2) at standard temperature and pressure (STP) is approximately 1.25 grams per liter (g/L).
To understand this, we need to consider what STP means. Standard temperature is defined as 0 degrees Celsius (273.15 K) and standard pressure is 1 atmosphere (atm). Under these conditions, one mole of any ideal gas occupies a volume of 22.4 liters.
Nitrogen gas has a molecular mass of about 28 grams per mole (since each nitrogen atom has a mass of about 14 grams, and there are two of them in N2). To calculate density, we can use the formula:
Density = Mass/Volume
At STP, the volume for 1 mole of N2 is 22.4 L. Thus, the density is:
Density = 28 g / 22.4 L ≈ 1.25 g/L
This means that at STP, nitrogen gas is relatively light compared to liquids and solids, which is why it’s commonly used in various industrial applications, including the production of fertilizers and in the food packaging industry.