Calculate the number of molecules of CH4 in 48g CH4?

To answer this question, you must understand how to convert grams of a molecule into the number of molecules. To do this, you have to utilize the concepts of moles and molar mass.

A mole is just a unit of measurement. Avogadro's number is equal to #6.022*10^23# molecules/mole. This number is the number of molecules of a specific compound in which when you multiply the compound by it, it converts atomic mass into grams.

For example, one mole of hydrogen gas (#H_2#) or #6.022*10^23# molecules of #H_2# weighs 2.016 grams because one molecule of #H_2# has an atomic weight of 2.016.

So the overall solution for this problem is to use molar mass of #CH_4# (methane) to convert grams of methane into moles of methane. Then, use Avogadro's number to convert moles of methane into molecules of methane.

One mole of methane equals 16.04 grams because a molecule of methane has an atomic weight of 16.04. The conversion factor will be 16.04 grams/mole.

#48g CH_4*(1 mol CH_4)/(16.04 g CH_4)* (6.022*10^23 mcls CH_4)/(1 mol CH_4) #

When you multiple and divide everything out, you get #1.8021 *10^24# molecules of #CH_4#

Notice this is a modified T-chart so the grams #CH_4# cancels out when you do the first conversion, and the moles #CH_4# cancels out when you do the second conversion. This leaves you with the unit molecules of #CH_4# which corresponds to what the question asks.