Using the answer from problem 8.61, how many grams of nitrogen are in Whitney's lungs at STP if air contains 78% nitrogen?

Verified step by step guidance

1. Identify the conditions of STP (Standard Temperature and Pressure), which are 0°C (273.15 K) and 1 atm pressure.
2. Recall that at STP, 1 mole of an ideal gas occupies 22.4 liters.
3. Determine the volume of air in Whitney's lungs using the answer from problem 8.61.
4. Calculate the volume of nitrogen in Whitney's lungs by multiplying the total volume of air by 0.78, since air contains 78% nitrogen.
5. Convert the volume of nitrogen to moles using the molar volume at STP (22.4 L/mol), and then convert moles to grams using the molar mass of nitrogen (N2, approximately 28.02 g/mol).

Key Concepts

Standard Temperature and Pressure (STP)

STP refers to a standard set of conditions used in chemistry, defined as a temperature of 0 degrees Celsius (273.15 K) and a pressure of 1 atmosphere (atm). Under these conditions, one mole of an ideal gas occupies 22.4 liters. Understanding STP is crucial for calculating gas volumes and conversions in stoichiometric problems.

Composition of Air

Air is primarily composed of nitrogen (approximately 78%), oxygen (about 21%), and trace amounts of other gases. This composition is essential for calculations involving the amount of nitrogen in a given volume of air. Knowing the percentage of nitrogen allows for the determination of its mass when the total volume of air is known.

Mass Calculation from Molar Volume

To find the mass of a gas, one can use the relationship between moles, molar mass, and volume. At STP, the molar volume of a gas is 22.4 L, and the molar mass of nitrogen (N2) is approximately 28 g/mol. By calculating the number of moles of nitrogen in a given volume of air and multiplying by its molar mass, the total mass of nitrogen can be determined.