Chemistry Stoichiometry Review

2H₂  +   O₂  →  2H₂O
How many moles of oxygen are consumed if 8 moles H₂ are used?

• 2
• 4
• 6
• 8

2 KClO₃ → 2 KCl + 3 O₂
How many moles of oxygen are produced when 6.7 moles of KClO₃ decompose completely?

• 6.7 mol
• 1.0 mol
• 10.05 mol

• 4.5 mol

For the Balanced Reaction: 3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe; What is the Ratio of moles of MgO to moles Fe?

• 3mol Mg / 2 mol Fe
• 2 mol Mg/ 3 mol Fe
• 1 mol Fe/ 2 mol Fe
• 3 mol MgO / 2 mol Fe

What is a Excess Reagent?

• amount you end with
• what you run out of first
• what you have left over
• what you start with

What is the first thing you must do to solve a stoichiometry problem?

• Write a Balanced Equation
• Panic
• Write an Unbalanced Equation
• Ask for help

2Na + 2H₂O → 2NaOH+ H₂ How many grams of hydrogen are produced if

120 g of Na are available?

• 5.27 g

• 2.63 g

• 690 g

• 45 g

Stoichiometry is -

• a balanced reaction with the same number of elements on both sides of the reaction

• Calculating moles

• using the balanced reaction and moles to calculate amounts needed and used

• percentage yield

What are the coefficients to balance the following:

Fe + CuCl₂ --> Cu + FeCl₃

• 1,1,1,1

• 2,3,3,2

• 3,2,3,2

• 4,6,6,4

When does a chemical reaction stop?

• When the lab is finished
• When the excess reactant is used up
• When the limiting reactant is used up
• Chemical reactions never stop

What is the mole ratio of HCl to CaCl₂ in this reaction:

Ca(OH)₂ + 2 HCl --> CaCl₂ + 2 H₂O

• 2:2

• 1:1

• 1:2

• 2:1