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Active mass refers to the effective concentration of a substance in a reaction. In general, it represents how much of a substance is available to participate in a reaction. In the context of gases, active mass is often measured in terms of concentration, such as molarity. Molar concentration is a direct measure of active mass in solutions, but in the gaseous state, it is influenced by factors such as temperature and pressure. In this exercise, since each gas is at an equal concentration of 1 gram per liter, the active mass is directly linked to the molar concentration, as molar mass influences how many moles of a gas are present in a given volume.

Molar concentration, or molarity, is a measure of the concentration of a solute in a solution. It is expressed in moles per liter (mol/L). To find the molar concentration of a gas, you need to divide the mass of the gas by its molar mass and the volume it occupies.

• Formula for molarity: \[\text{Molarity} = \frac{\text{mass of gas (g)}}{\text{molar mass of gas (g/mol)}}\]

For this problem, the molarity of each gas helps us compare their active masses. The gases in the mixture all have the same mass per volume, meaning their molarity (or active mass) will vary depending on their molar mass—the heavier the molar mass, the smaller the molarity, and vice versa.

A gaseous mixture consists of different types of gases present in a single container. Each gas behaves independently in terms of pressure, volume, and concentration. This property follows Dalton's Law of Partial Pressures, which states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of individual gases. However, in this exercise, we are more focused on their molarity or molar concentration to analyze the active mass rather than pressure.In our example, since the gases \(\text{NH}_3\), \(\text{N}_2\), \(\text{H}_2\), and \(\text{O}_2\) are mixed, and each is present in equal gram per liter concentration, their individual molarities are crucial to determine their sequence in active mass, not their interactions with each other.

Molar mass is a critical factor in determining the molar concentration of a gas. It tells us how much one mole of a substance weighs and is expressed in grams per mole (g/mol). The molar mass can be calculated by adding the atomic masses of the constituent elements. This calculation is essential to convert the mass of a gas into moles, allowing us to calculate molarity.For example, with the gases in our exercise:

• \( \text{NH}_3 \): Calculated as \( 14 + 3 \times 1 = 17 \text{ g/mol} \)
• \( \text{N}_2 \): Calculated as \( 2 \times 14 = 28 \text{ g/mol} \)
• \( \text{H}_2 \): Calculated as \( 2 \times 1 = 2 \text{ g/mol} \)
• \( \text{O}_2 \): Calculated as \( 2 \times 16 = 32 \text{ g/mol} \)

Understanding how to calculate molar mass allows you to determine the number of moles of the gas you have, which is vital for calculating molar concentration and comparing active masses in mixtures.