WorksheetsBond energy
Total questions: 8
Worksheet time: 4mins
Which statements about exothermic reactions are correct?
I. They have negative ΔH values II. The products have a lower enthalpy than the reactants III. The products are more energetically stable than the reactants
I and II only
I and III only
II and III only
I, II, and III
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
