New tre Dalton's Atomic Theory Quiz
Sodium chloride, NaCl, can be formed by the reaction of sodium metal, Na, and chlorine gas, Cl2, as summarized in the chemical equation below.
2 Na
+ Cl2 --> 2 NaCl
If 45.98 g of sodium, Na, combines with an excess of chlorine gas, Cl2, to form 106.89 g of sodium chloride, NaCl, what is mass of chlorine used in
the reaction?
O 0.3934 g Cl2
O 12.542 g Cl2
O 60.91 g Cl2
152.87 g Cl2
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n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.

the answer is 303.15 or 303