Chapter 11 : StoichiometrySection2 : Stoichiometric calculations

Objectives Describe the types of relationships indicated by a balanced chemical equation.

Mole to mole conversionMole to mass conversion

Rally coach:Find all possible mole ratios for the

following equation:-

____ PbBr2 + ____ HCl ____ HBr + ____ PbCl2

Stoichiometric mole-to-mole conversion Reaction between potassium and water 2K(s) + 2 H 2 O(l) → 2KOH(aq) + H 2 (g)

Q1 : how much hydrogen is produced if only 0.0400 mol of potassium is used?

Known Unknown

K= 0.0400 mole H2 = ? moles

Known mole

Unknown mole

Known Unknown

K= 0.0400 mole H2 = ? moles

Answer the following: For the following equation

C 3 H 8 (g) + O 2 (g) → C O 2 (g) + H 2 O(g)How many moles of C O 2 are produced when 10.0 mol of C 3 H 8 are burned in excess oxygen in a gas grill?The answer:

Balance the equations

Follow the way shown above

So C 3 H 8 (g) + 5 O 2 (g) → 3C O 2 (g) + 4 H 2

O(g)

Known Unknown

C 3 H 8 = 10.0 moles C O 2 = ? moles

Stoichiometric mole-to-mass conversionDetermine the mass of sodium chloride (NaCl), commonly called table salt, produced when 1.25 mol of chlorine gas ( Cl 2 ) reacts with sodium

The answer :

1- Write the balanced chemical equation2Na(s) + C l 2 (g) → 2NaCl(s)

2-

Now ,we have the moles of one substance and we need the mass ( grams ) of anther substance so ,

Known Unknown

1.25 mol Cl2 ?grams of NaCl

Known

mole

Unknown mole

Unknown

grams

3-known mole to unknown mole

4- unknown mole to unknown grams