Chemistry: 3.4 - Molar Mass

Ultimately, what is a chemical compound

A chemical compound is, ultimately, a collection of atoms.

molar mass

the volume of one mole of an ideal gas; equal to 22.42 liters at STP Standard temperature and pressure (STP) the condition 0℃ and 1 atmosphere of pressure

example of chemical compound, ultimately, being a collection of atoms.

For example, methane (the major component of natural gas) consists of molecules that each contain one carbon and four hydrogen atoms (CH₄). How can we calculate the mass of 1 mole of methane; that is, what is the mass of 6.022 × 10²³ CH₄ molecules? Since each CH₄ molecule contains one carbon atom and four hydrogen atoms, 1 mole of CH₄ molecules contains 1 mole of carbon atoms and 4 moles of hydrogen atoms. The mass of 1 mole of methane can be found by summing the masses of carbon and hydrogen present: Mass of 1 mol C = 12.01 g Mass of 4 mol H = 4 × 1.008 g Mass of 1 mol CH₄ = 16.04 g (In this case, the term 12.01 limits the number of significant figures) Because 16.04 g represents the mass of 1 mole of methane molecules, it makes sense to call it the 𝑚𝑜𝑙𝑎𝑟 𝘮𝑎𝑠𝑠 for methane.

How is the molar mass of a known substance obtained?

The molar mass of a known substance is obtained by summing the masses of the component atoms

What is the molar mass of a substance?

The molar mass of a substance is 𝑡ℎ𝑒 𝑚𝑎𝑠𝑠 𝑖𝑛 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 A substance's molar mass is the mass in grams of 1 mole of the substance.