Lesson: Stoichiometry

Stoichiometry

​What is Stoichometry

the relationship between the relative quantities of substances taking part in a reaction or forming a compound. In another word, the relationship between the amount of reactants and products in a reaction.

Fill in the Blanks

Given the chemical equation: La + I₂ → LaI₃

If 6.4 moles of LaI₃ are produced, how many moles of La were reacted?

​1 Step Stoichiometry

​2 Steps Stoichiometry

​Conversion Factors:

1 mole = molar mass (g) = 6.02 x 10²³ particles = 22.7 L

Mole Ratio

Given x conversion factor x mole ratio x conversion factor

​Stoichiometry: Railroad Tracks Method

​Stoichiometry: Proportion Method

Given x conversion factor x mole ratio x conversion factor

​Step in solving stoichiometry problems.

1. Write the given value, unit, and substance

2. Convert the given to mole of the given

3. Convert mole of given substance to mole of the want substance

4. Convert mole of wanted substance to unit of the want substance

Multiple Choice

2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

• 5.2 g
• 2.6 g
• 690 g
• 45 g

​2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

​Given: 120 g Na
Want: g of H₂

​Map: g Na → mol Na→ Mol H₂ → g H₂

​Convert g Na to mol Na

​Method 1: Individual Steps

​2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

​Given: 120 g Na
Want: g of H₂

​Map: g Na → mol Na→ Mol H₂ → g H₂

​Convert mol Na to mol H₂ using the mole ration fromt he balanced chemical equation

​2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

​Given: 120 g Na
Want: g of H₂

​Map: g Na → mol Na→ Mol H₂ → g H₂

​Convert mol H₂ to grams of H₂

​2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

​Given: 120 g Na
Want: g of H₂

​Map: g Na → mol Na → Mol H₂ → g H₂

​Method 2 Combine all the steps