How many moles of #"Al"# are needed to form #3.7# moles of #"Al"_2"O"_3#?

#4"Al" + 3"O"_2 -> 2"Al"_2"O"_3#

1 Answer

Answer:

#"7.4 mol Al"#

Explanation:

The balanced chemical equation for it is

# 4Al + 3O_2 -> 2Al_2O_3 #

You have #3.7# moles of #Al_2O_3#. When you balanced the equation, you got #2# moles of #"Al_2O_3# and #4# moles of #Al#, so

"4 mol #Al# gives #2# mol #Al_2O_3#

After you cancel out the units of measurement to check the order of the conversion, multiply #3.7# with #4# and then divide the answer by #2#. You get #7.4# moles of #Al#.