100 grams of magnesium and 2.50 grams of oxygen react together in synthesis reaction to form magnesium oxide. How do you write this balanced reaction?

1 Answer
anor277
Apr 30, 2016

The balanced equation is clearly:

#Mg(s) + 1/2O_2(g) rarr MgO(s)#

Explanation:

It is abundantly clear that magnesium is in vast molar excess:

i.e. #"Moles of metal"# #=# #(100*g)/(24.31*g*mol^-1)# #~=# #5*mol#

#"Moles of dioxygen"# #=# #(2.5*g)/(32.00*g*mol^-1)# #~=# #0.08*mol#

Clearly, #O_2# is the limiting reagent, and our calculation proceeds on the basis of the molar quantity of the gas.

Related questions
See all questions in Chemical Reactions and Equations
Impact of this question
1893 views around the world
You can reuse this answer
Creative Commons License