Howe would you calculate the number of moles of Cl atoms in #3.61x10^24# formula units of magnesium chloride, #MgCl_2#?

2 Answers
Mar 26, 2017

Use Avogadro’s number to calculate the number of moles of #MgCl_2#. The number of moles of Cl is twice as much, because the ratio of Cl in #MgCl_2# to #MgCl_2# is 2:1.

#(3.61*10^24)/(6.022*10^23) = 5.99#
Therefore, there are 12 moles of Cl.

Mar 26, 2017

Answer:

There are #7.22xx10^24# atoms #"Cl"# in #3.61xx10^24# formula units of #"MgCl"_2"#.

Explanation:

Each formula unit of magnesium chloride, #"MgCl"_2"#, contains two chlorine, #"Cl"#, atoms.

Multiply the number of formula units by the conversion factor

#(2color(white)(.)"atoms Cl")/(1color(white)(.)"formula unit MgCl"_2#.

#3.61xx10^24color(red)cancel(color(black)("formula units MgCl"_2))xx(2color(white)(.)"atoms Cl")/(1color(red)cancel(color(black)("formula units MgCl"_2)))=7.22xx10^24"Cl atoms"#