Download PRACTICE * Naming and Writing Ionic Compounds

Chemistry
Unit Six
PRACTICE – Energy and Chemical Changes – Part I
1. Label each area on the reaction diagram with the appropriate letters listed below. Not all letters
will be used.
A.
reactants
B.
products
C.
∆H
D. activation energy (Ea)
E.
activation complex
F.
energy absorbed
PE
(kJ)
G. energy released
Reaction Pathway
For #2-5, specify whether each reaction is exothermic (EXO) or endothermic (ENDO).
2. ________ The reaction shown in the diagram above.
3. ________ Steam rising from the shower.
4. ________ 4Fe(s) + 3O2(g) → 2Fe2O3(s) + energy
5. ________ A test tube that feels cold to the touch after two substances have been
mixed.
6. Using Hess’s Law, calculate the heat of reaction for the following reaction:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
CH4
O2
CO2
H2O(g)
∆Hf°
∆Hf°
∆Hf°
∆Hf°
= - 17.9kJ/mol
= 0kJ/mol
= - 393.5kJ/mol
= - 241.8kJ/mol
7. Calculate the heat given off when one mole of B5H9 reacts with excess O2 according to the
following reaction:
2B5H9(g) + 12O2(g) → 5B2O3(g) + 9H2O(g)
Compound
B5H9(g)
B2O3(g)
O2(g)
H2O(g)
Hf° (kJ/mol)
73.2
-1272.77
0
-241.82
Answer the following questions using the energy diagram below.
8. __________________ Is the forward reaction represented by the curve exothermic or
endothermic?
9. ___________________ Estimate the magnitude and sign of H.
10. __________________ Estimate E a' .