The Heat of Formation of Magnesium Oxide CHEM 1411 EXPERIMENT
Lab Report Assignment
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Pre-Lab Questions
In determining the Heat of Formation of MgO, you will be using Hess' Law. You will be using the three following reactions:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) (Eqn.1)
MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(b) (Eqn.2)
2H2(g) + O2(g) → 2H2O(l) (Eqn.3)
a. Using Hess' Law, these equations can be rearranged to give the overall reaction of interest for this experiment (Eqn.4):
Mg(s) + 1/2O2(g) → MgO(s) (Eqn.4)
What must be done with Equation 1? (Reversed? Multiplied by a factor? If so, what factor? Left as is?)
What must be done with Equation 2?
What must be done with equation 3 ?
b. In lab you will be determining the values of ΔH for the Mg and MgO reactions (Eqn.1, Eqn.2). IF one of those values of ΔH is negative and that reaction is reversed when applying Hess' Law, what sign will the value of ΔH have for that reaction?
c. What is the meaning of a negative enthalpy value?
Beginning Question
Enter your beginning question for this experiment.
Safety Considerations
What are the safe