Which sample contains more molecules: 1.00 L of O2 at STP, 1.00 L of air at STP, or 1.00 L of H2 at STP?

Verified step by step guidance

Understand that at Standard Temperature and Pressure (STP), 1 mole of any ideal gas occupies 22.4 L.

Recognize that the number of molecules in a gas sample is directly proportional to the number of moles of the gas.

Since all samples are 1.00 L and at STP, calculate the number of moles for each gas using the formula: \( \text{moles} = \frac{\text{volume (L)}}{22.4 \text{ L/mol}} \).

Apply the formula to each gas: O2, air, and H2, to find the number of moles in each 1.00 L sample.

Compare the number of moles for each gas to determine which sample contains more molecules, as more moles mean more molecules.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Avogadro's Law

Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules. This principle is fundamental in determining the number of molecules in a given volume of gas, allowing us to compare different gases under identical conditions.

Standard Temperature and Pressure (STP)

Standard Temperature and Pressure (STP) is defined as a temperature of 0 degrees Celsius (273.15 K) and a pressure of 1 atmosphere (atm). At STP, one mole of any ideal gas occupies a volume of 22.4 liters, which is crucial for calculating the number of moles and, consequently, the number of molecules in a gas sample.

Composition of Air

Air is primarily composed of nitrogen (approximately 78%), oxygen (about 21%), and trace amounts of other gases, including argon and carbon dioxide. When comparing the number of molecules in 1.00 L of air to pure gases like O2 and H2, it is essential to consider the molar composition of air, as it affects the total number of molecules present in the same volume.

Recommended video:

Guided course

04:19

Matter Composition

Related Practice

Textbook Question

Assume that you have a cylinder with a movable piston. What would happen to the gas volume of the cylinder if you were to do the following? (a) Halve the Kelvin temperature while holding the pressure constant

Textbook Question

Assume that you have a cylinder with a movable piston. What would happen to the gas volume of the cylinder if you were to do the following? (b) Increase the amount of gas by one-fourth while holding the temperature and pressure constant

Textbook Question

Assume that you have a cylinder with a movable piston. What would happen to the gas volume of the cylinder if you were to do the following? (d) Double the Kelvin temperature and double the pressure

Textbook Question

A compressed air tank carried by scuba divers has a volume of 8.0 L and a pressure of 140 atm at 20 °C. What is the volume of air in the tank in liters at STP?