STOICHIOMETRY (2) !!

Example 1 :
a) How many grams of Fe(Ⅱ) will be needed to react with 3.20 mol of HCl?

Step1: Balance the equation.
1Fe + 2HCl → 1FeCl2 + 1H2

Step2: Make a "ROAD MAP"

Step 3: Do calculation

3.2 mol HCl × 1mol Fe/ 2mol HCl × 56g Fe/ 1mol Fe = 90g Fe

b) How many grams of Fe will be needed to produce 10.0 g H2

10.0 g × 1mol/2.0 g H2 × 1mol Fe/ 1mol H2 × 56 g Fe/1 mol Fe =280 g Fe

Note: grams (X) ↔ mol(x) ↔ mol(y) ↔ grams(y)

Example 2 :

a) Using the following equation : 2 NaOH + 1H2SO4 → 2H2O + 1Na2SO4

How many grams of sodium sulphate will be formed if you start with 200 grams of sodium hydroxide?

200 g NaOH × 1mol NaOH/ 40 g × 1mol Na2SO4/2 mol NaOH × 355.3g Na2SO4/ 1mol = 888.25 g

                                                                                                                                            = 900 g