Enthalpies of Reaction Lab Quiz RETAKE: steps of calculating the enthalpy change
Step 1
find mols of both reactants
Step 2
find temperature change by inputting the value before the increase into the equation. subtract the minimum value from the calculated value
Step 3
write Q = mc delta t
Step 4
input into mc delta t
What goes into mc delta t?
m = volume of cm³
c = 4.18
delta t = change in temperature
Step 5
change Q (which is in joules) to kJ
Step 6
divide kJ by mols of limiting reactant
What is important to remember about the calculated enthalpies?
They should be negative because they are exothermic
Are the enthalpies endothermic or exothermic and why?
Exothermic because heat is being released
How to use Hess’s Law
Rewrite reactions to get reactants and products on the correct side. Use calculated enthalpies to find enthalpy of the third reaction
What is the formula for percent error?
|experimental - literature value| / literature value
multiply by 100 to get percent