Suppose a mixture contains helium and oxygen gases. If the partial pressure of helium is the same as the partial pressure of oxygen, what do you know about the number of helium atoms compared to the number of oxygen molecules? Explain.

Verified step by step guidance

1. Identify the concept of partial pressure: In a mixture of gases, each gas exerts a pressure independently of the others, known as its partial pressure.
2. Apply Dalton's Law of Partial Pressures: The total pressure of a gas mixture is the sum of the partial pressures of each individual gas.
3. Understand the relationship between partial pressure and moles: According to the ideal gas law, the partial pressure of a gas is directly proportional to the number of moles of that gas, assuming constant temperature and volume.
4. Since the partial pressures of helium and oxygen are equal, infer that the number of moles of helium is equal to the number of moles of oxygen.
5. Recognize the difference in particles: Helium is a monoatomic gas (He), while oxygen is diatomic (O_2). Therefore, the number of helium atoms is equal to the number of oxygen molecules.

Key Concepts

Dalton's Law of Partial Pressures

Dalton's Law states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of each individual gas. This principle helps us understand how gases behave in mixtures and allows us to relate the partial pressures to the number of moles of each gas present.

Mole Concept

The mole concept is a fundamental principle in chemistry that relates the amount of substance to its mass and volume. One mole of any gas at standard temperature and pressure (STP) occupies the same volume, which means that the number of moles can be directly related to the number of particles, such as atoms or molecules, in a given volume.

Ideal Gas Law

The Ideal Gas Law (PV=nRT) describes the relationship between pressure (P), volume (V), temperature (T), and the number of moles (n) of a gas. This law allows us to understand how changes in one variable affect the others, and it is particularly useful for comparing the behavior of different gases under the same conditions, such as in the case of helium and oxygen in this question.