How many molecules are in 3 moles of #H_2S#?

1 Answer
Jun 27, 2016

Answer:

#1.8 * 10^(24)"molecules"#

Explanation:

As you know, a mole is simply a very, very large collection of molecules.

In order to have one mole of a molecular substance, you need to have #6.022 * 10^(23)# molecules of that substance #-># this is known as Avogadro's number and it can be used as a conversion factor to go from number of molecules to moles and vice versa.

#color(blue)(|bar(ul(color(white)(a/a)"1 mole" = 6.022 * 10^(23)"molecules"color(white)(a/a)|)))#

Now, you want to know how many molecules are present in #3# moles of hydrogen sulfide, #"H"_2"S"#.

According to Avogadro's number, #1# mole of hydrogen sulfide contains #6.022 * 10^(23)# molecules of hydrogen sulfide, which means that #2# moles will contain

#3 color(red)(cancel(color(black)("moles H"_2"S"))) * overbrace((6.022 * 10^(23)"molecules H"_2"S")/(1color(red)(cancel(color(black)("mole H"_2"S")))))^(color(blue)("Avogadro's number")) = color(green)(|bar(ul(color(white)(a/a)color(black)(1.8 * 10^(24)"molecules H"_2"S")color(white)(a/a)|)))#

I'll leave the answer rounded to two sig figs.