Chemistry set 9

Q.6 Reactants have high energy than products in:
A) Exothermic reactions C) Photochemical reactions
B) Endothermic reactions D) Non-spontaneous reactions

Q.7 2H2 + O2 2H2O ∆H = +285.5 kJ mol-1
What will be the enthalpy change in the above reaction?
A) 205.5 kJ/mol C) -205.5 kJ/mol
B) Zero kJ/mol D) 1 kJ/mol

Q.9 The equation that represents standard enthalpy of atomization of hydrogen is:
A) 1
2 H2O(l) H2(g) + 1 2 O(g) +218 kJ mol-1 C) 1 2 H2(g) H(g) +218 kJ mol-1
B) 1
2 H2O(l) H2(g) + 1 2 O(g) –218 kJ mol-1 D) 1 2 H2(g) H(g) –218 kJ mol-1
Q.10 Standard enthalpy of combustion of graphite at 25 oC is –393.51 kJ mol-1 and that of diamond
is –395.41 kJ mol-1. The enthalpy change for graphite is:
A) – 1.91 C) –2.1
B) +2.1 D) +1.91

Q.11
1 2
H2(g) H(g) ΔH = 218 kJmol-1
In this reaction, ΔH will be called:
A) Enthalpy of atomization C) Enthalpy of formation
B) Enthalpy of decomposition D) Enthalpy of the dissociation
Q.12 Mg +
1 2
O2(g) MgO(g) + -692 kJmol-1 at STP.
Enthalpy of the above reaction will be called:
A) ΔH°at C) ΔH°sol
B) ΔH°s D) ΔH°l