Unit 4: Chemical Attractions

What is a limiting reactant?

• the reactant that determines how much product can be made
• the reactant that is in excess
• the product that you can make the most of
• the amount of reactants that react with each other

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 12 moles of O₂ reacts with 1.1 mole of C₁₀H₈ what is the limiting reactant?  C₁₀H₈ + 12 O₂ --> 10 CO₂ + 4 H₂O

• Oxygen
• C₁₀H₈
• Water
• Carbon Dioxide

CH₄ + 2H₂O --> CO₂ + 4H₂
What is the limiting reactant when 20g CH₄ react with 15g H₂O?

• CH₄
• H₂O
• CO₂
• H₂

Use the equation 2 Al + 3 Cl₂ ---> 2 AlCl₃.  If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.

• AlCl3
• Cl2
• Al

Fe + S --> FeS
If 7.62g Fe react with 8.67g S, what is the limiting reactant?

• Fe
• S
• FeS
• none 

SO₂ + PCl₅ --> SOCl₂ + POCl₃
How much SOCl₂ is produced when 16.2g SO₂ react with 13.7g PCl_5? 

• 7.87g
• 30.1g
• 26.4g
• 19.8g 

Determine the solubility for the substances at 55'C and arrange them in order from lowest to highest solubility.

• NaCl, NH4Cl, KBr, NaNO3

• NaCl, NH4Cl, NaNO3, KBr

• NH4Cl, NaCl, NaNO3, KBr

• NaNO3, KBr, NH4Cl, NaCl

How could you change a saturated solution to an unsaturated solution?

• Add solvent

• Add solute

Identify a method to decrease the dissolving rate of a solution:

• decrease the temperature

• add KE

• stir the solution

• increase the temperature