Chemistry Q3 Review

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

KNO₃ --> KNO₂ + O₂
What coefficients are needed to balance the reaction?

• 2, 2, 1
• 2, 3, 2
• 1, 2, 2
• 1, 3, 1

O₂ + CS₂ --> CO₂ + SO₂
What coefficient would go in front of the O₂?

• 1
• 2
• 3
• 4

 The equation for Percent Yield:

• (predicted/experimental) X 100
• (experimental/predicted) X 100
• (experimental - predicted)/ Predicted X 100

True or False. You must convert grams to moles to do stoichiometry.

• True
• False

2H₂   +   O₂  →  2H₂O
How many moles of water can be produced if 8 moles H₂ are used?

• 4 moles
• 8 moles
• 16 moles
• 2 moles

What is a Limiting Reagent?

• speeds up a reaction
• what you run out of first
• what you have left over
• slows down a reaction

What is a Excess Reagent?

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

You need 2 pieces of bread, 1 tablespoon of peanut butter and 2 tablespoons of jelly to make a sandwich.  If you have 10 pieces of bread, 4 tablespoons of peanut butter and 20 tablespoons of jelly, what is the limiting reactant?

• bread
• jelly
• peanut butter
• sandwich

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