Question #30788

1 Answer

From the balanced equation 46 grams of Nareacts with 71 grams of Cl_2 gas to form 117 grams of NaCl (numbers obtained from the molar mass/atomic mass)

The law of conservation of mass says that the mass of reactants equals the mass of products.

We can say that 2 moled of Na reacts with 1 mole of Cl_2 molecule to form 2 moles of NaCl.

We see the 117 g of NaCl is 117 g/117 g/mol = 1 mol

(Mole = mass/molar mass)

Hence 1 mole of NaCl will require 1 mole of Cl2 molecule (from the stoichiometry).

1 mole of Cl_2 molecule is equivalent to 2 moles of Cl atom and hence 2* 35.5 g = 71 g.

I would be curious to find out how you got 69.9 grams.

The questioner asked how one can set up the Stoichiometry of this equation. Stoichiometry is nothing but the ratio of reacting species in the balanced chemical equation. In the above equation, one can write,

mol Cl_2: mol NaCl is 1 : 1

Hence the masses of Cl_2 and NaCl would be equivalent.