Question

when 2.40 moles of sodium react with 5.90 moles of chlorine gas in the reaction shown above, how many moles of sodium chloride are produced ?

Answer 1

First we look at the chemical reaction:

2 Na + Cl₂ → 2 NaCl

Now we should see which is the limiting reagent, so we construct the following reasoning:

if        2 moles of Na reacts with 1 mole of Cl₂

then   2.4 moles of Na reacts with X moles of Cl₂

X = (2.4 × 1) / 2 = 1.2 mole of Cl₂ (way lower that the available quantity of chlorine).

So the limiting reagent is sodium, and from here we can calculate the number of moles of NaCl produced.

if        2 moles of Na produces 2 moles of NaCl

then   2.4 moles of Na produces Y moles of NaCl

Y = (2.4 × 2) / 2 = 2.4 moles fo NaCl (sodium chloride)