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Worksheetsquiz 3 - 1 sec - Bond Energy
Total questions: 14
Worksheet time: 4hrs 30mins
The average bond enthalpies for O-O and O=O are 146 and 496 kJ/mol respectively. What is the enthalpy change, in kJ, for the reaction below?
H-O-O-H(g) → H-O-H(g) + ½O=O(g)
-102
+102
+350
+394
When the solids Ba(OH)2 and NH4SCN are mixed, a solution is produced and the temperature drops. Which statement about the energetics of this reaction is correct?
The reaction is endothermic and ΔH is negative
The reaction is endothermic and ΔH is positive
The reaction is exothermic and ΔH is negative
The reaction is exothermic and ΔH is positive
The following equation shows the formation of magnesium oxide from magnesium metal. Which statement is correct for this reaction?
2Mg(s) + O2(g) → 2MgO(s) ΔH = -1204 kJ
1204 kJ of energy are released for every mole of magnesium reacted
602 kJ of energy are absorbed for every mole of magnesium oxide formed
602 kJ of energy are released for every mole of oxygen reacted
1204 kJ of energy are released for every two moles of magnesium oxide formed
For the reaction 2H2(g) + O2(g) → 2H2O(g) the bond enthalpies (in kJ/mol) are
H-H = x, O=O = y, O-H = z
Which calculation will give the value, in kJ/mol, of ΔH for the reaction?
2x + y - 2z
4z - 2x - y
2x + y - 4z
2z - 2x - y
Does breaking bonds require energy, release energy, or not involve energy at all?
requires energy to break
releases energy when broken
No energy involved
What kind of energy change happens in the photosynthesis reaction in plant leaves?
Endo
Exo
No change
Burning leaves and burning a fuel provide a(n) _______ change.
endothermic
exothermic
physical
When new chemical bonds form, energy ____________.
is taken into the system.
is released from the system.
stays the same in the system.
In a reaction old bonds _______ and new bonds _______.
form , break
break, form
stay, added
Is this equation endo- or exo-thermic?
PCl3 (s) + Cl2 (g) --> PCl5 (s) + energy
endothermic
exothermic
Is this equation endo- or exo-thermic?
2KNO3 (s) + energy --> 2KNO2 (s) + O2
endothermic
exothermic
Is this reaction endo- or exo-thermic?
NH4NO2 + energy --> N2 (g) + 2H2O (g)
endothermic
exothermic
