Skip to main content
Ch.5 - Gases
Chapter 5, Problem 87

A sample of neon effuses from a container in 76 seconds. The same amount of an unknown noble gas requires 155 seconds. Identify the second gas.

Verified Solution

Video duration:
3m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

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

Graham's Law of Effusion

Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass. This means that lighter gases effuse faster than heavier gases. The relationship can be expressed mathematically as (Rate1/Rate2) = √(Molar Mass2/Molar Mass1), allowing for the comparison of effusion rates between two gases.
Recommended video:
Guided course
01:14
Graham's Law of Effusion

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is a critical factor in determining the behavior of gases, including their rates of effusion. For noble gases, molar masses vary significantly, which influences their effusion rates and can be used to identify unknown gases when compared to known values.
Recommended video:
Guided course
02:11
Molar Mass Concept

Noble Gases

Noble gases are a group of elements in Group 18 of the periodic table, known for their low reactivity due to having a full valence shell of electrons. Common noble gases include helium, neon, argon, krypton, xenon, and radon. Each noble gas has a distinct molar mass, which is essential for calculations involving effusion and can help identify unknown gases based on their effusion rates.
Recommended video:
Guided course
00:44
Noble Gas Compounds Example