Thermochemistry
Level 2
Serial Multiple Choice
The next 2 questions
relate to the information below:
I. C(s) + O2(g) à CO2(g) +
393.3 kJ; II.
CO(g) + 1/2 O2(g) à CO2
+ 282.8 kJ.
309. On the basis of the
information given in equation II and assuming no change in
temperature or pressure, one can correctly conclude that
1)
The rate of the reaction is rapid.
2) The total number of moles of product is
the same as the total number of moles
of reactants.
3) The reaction is exothermic.
4) The masses of the product is greater
than those of the reactants.
5) There will be an increase
in volume of reactants and products taken together as
the reaction proceeds.
ANS: 3
310. When 112 grams of CO are
used, which of the following occurs?
1) 1.0 mole of CO2 is produced.
2) 282.8 kJ of heat are generated. 4)
0.25 mole of CO2 is produced.
3) 2.0
moles of O2 are consumed. 5) 0.5 mole of O2 is
consumed.
ANS: 3
The next 2 questions deal with the following reactions:
I. Se(s)
+ O2(g) à SeO2(g); DH = -397.9 kJ
II.
Se(s) + 1.5 O2(g) à SeO3(g); DH = -297.1 kJ
III.
SeO2(g) + 1/2 O2(g) à SeO3(g).
311.
The heat of reaction, DH, for reaction III is:
1) –100.8 kJ; 2) +100.8 kJ; 3) –195.4 kJ; 4) +267.4 kJ; 5) –199.0 kJ.
ANS: 2
312. Which statement about
these three reactions is false?
1) In each case, the heat content of the
reactants is greater than that of the products.
2) The first two reactions are exothermic,
the third is endothermic.
3) The potential energy of the reactants of
the third reaction is less than the product’s
potential energy.
4) The potential energy in
the product of the 1st reaction is less than the potential
energy in the
reactants of that reaction.
5) The kinetic energy in the reactants of
the 3rd reaction is greater than the product’s
kinetic energy.
ANS: 1
The next 3 questions
use the equations below:
I. C6H6(l) + __ O2(g) à ___ CO2(g) + __
H2O(l)
II. 6 C(s) + 3 H2(g) + 82.8
kJ à C6H6(l)
III. C(s) + O2(g) à CO2(g) +
393.3 kJ
IV. H2(g) + ½ O2(g) à H2O(l) +
285.8 kJ.
313. The heat of formation,
DH,
of 1 mole of C6H6(1) is:
1) –13.8 kJ; 2) –82.8 kJ; 3) +82.8 kJ; 4) –679.1 kJ; 5) +679.1 kJ.
ANS: 3
314. The coefficient for O2
in the combustion of 1 mole of C6H6(1) is
1) 5; 2) 7; 3) 7.5; 4) 15; 5) 9.
ANS: 3
315. The heat of combustion of one mole C6H6(l)
in equation I is obtained by combining
equations in which of the of
ways?
1) 6 III + 3 IV + II 3) 6 III - 3 IV + II
2) –6 IV + 3 IV + II 4) 6 III + 3 IV – II 5) 6 III + 6 IV + II
ANS: 4