Today’s goal is for you to connect symbols and molecular level understanding with observations! We’ll also do some review for your quizzes next week and you’ll practice predicting single replacement reactions.


  1. What kind of reaction occurs between a pure element and a compound?
  2. When Mg reacts with Aluminum chloride, will Mg bond with Al or Cl? How do you know?
  3. Write a balanced equation (with state symbols) for the reaction between elemental magnesium with aqueous aluminum chloride.
  4. What is the type of energy used to convert Mg from a neutral atom to a positive ion?
  5. If 0.50 g of Mg reacts with 50.0 mL of 0.50 M AlCl3 what mass of precipitate will form? How many moles of excess reactant will be left? (ans: 0.37 g precipitate and 0.011 moles excess reactant)
  6. How could you recover the precipitate?
  7. How could you determine the concentration of mercury ions dissolved in a sample of water using a double displacement reaction?
The warm-up took about 30 minutes or so since some of you are still having difficulty with limiting reactant problems.   The rest of class you completed the chemical change lab.  The point of this was to connect observations to symbols to molecular level understanding so instead of doing all the analysis questions, you worked primarily on #7.
Homework: Finish Chemical Change Lab, Study for Limiting Reactant Quiz