Problems B
227
current is passed through the heater, the temperature of the mixture rises
until the dnodobenzene starts to melt, at this point, all of the electrical
energy is used for fusion and none for raising the temperature A current
of 0 500 amp passing for 6 mm 49 sec is required for the period in which
the temperature stays constant and before the temperature again begins to
rise, as both the water and the liquid dnodobenzene rise above the melting
point of 27°C Write the equation for the "reaction "
29 (;) Use Table 14-1 to determine the standard enthalpy of reaction (in kcal)
for each of the accompanying reactions
00 Give the values of the standard enthalpies of reaction in kjoules
(in) Calculate the change in standard internal energy (AE°) for each of the
reactions
(a) C (s) + H 2 0 (s) ?± H 2(fll + C0 (fl)
(b) C 6 H 6(() + 7i0 2(9l ?± 6C0 2(9l + 3H 2 0 ((1
(c) 2K (S) + H 2 SO 4(M) <=* K 2 SO 4(M) + H 2(9)
(d) N 2 0 (9) + H 2(91 ^ H 2 O U) + N 2(9)
(e) NH 3(0) *± iN 2(fl) + liH 2(9)
(f) 2H 2 S (fl) + 30 2(fl) +* 2H 2 0 U1 + 2S0 2(fl)
30 Calculate the standard enthalpy change (per mole) for the following reactions
Also write the equation for the reaction in each case
(a) Dissolving HC1 in water
(b) Combustion of C 4 H 10 vapor
(c) Combustion of liquid C 2 H 5 OH
(d) The production of PC1 5 from PC1 3
(e) The reaction of metallic zinc with dilute H 2 SO 4
31 The enthalpy of combustion of diamond is —94 50 kcal/mole The enthalpy of
combustion of graphite is -9405 kcal/mole What is the standard enthalpy
and entropy of transition from diamond to graphite
9
32 Calculate the standard enthalpy and entropy of vaporization of C 6 H 6 at
250°C
33 Calculate the bond energies in the following gaseous molecules (a) CO, (b)
CO 2 , (c) SO 2 , (d) NaCl The enthalpy of sublimation of NaCl is A// = +54 70
kcal/mole, and the standard enthalpy of formation of NaCl,,, is A//° = -98 23
kcal/mole
34 The observed heat of combustion at constant volume of a common fat,
glyceryl tnoleate (C 57 Hi 04 O 6(s) ) at 25 0°C is A£° = 7986 kcal/mole
(a) Write the equation for the combustion reaction and calculate A//° for the
reaction
(b) Calculate the standard enthalpy of formation of glyceryl tnoleate
(c) The overall metabolism of this fat in your body is the same as the combus
tion reaction in the bomb calorimeter Calculate how much heat is produced in your body for every ounce of this fat that you eat and metabolize
How much heat energy would your body produce while getting rid of one
pound of this fat
9
227
current is passed through the heater, the temperature of the mixture rises
until the dnodobenzene starts to melt, at this point, all of the electrical
energy is used for fusion and none for raising the temperature A current
of 0 500 amp passing for 6 mm 49 sec is required for the period in which
the temperature stays constant and before the temperature again begins to
rise, as both the water and the liquid dnodobenzene rise above the melting
point of 27°C Write the equation for the "reaction "
29 (;) Use Table 14-1 to determine the standard enthalpy of reaction (in kcal)
for each of the accompanying reactions
00 Give the values of the standard enthalpies of reaction in kjoules
(in) Calculate the change in standard internal energy (AE°) for each of the
reactions
(a) C (s) + H 2 0 (s) ?± H 2(fll + C0 (fl)
(b) C 6 H 6(() + 7i0 2(9l ?± 6C0 2(9l + 3H 2 0 ((1
(c) 2K (S) + H 2 SO 4(M) <=* K 2 SO 4(M) + H 2(9)
(d) N 2 0 (9) + H 2(91 ^ H 2 O U) + N 2(9)
(e) NH 3(0) *± iN 2(fl) + liH 2(9)
(f) 2H 2 S (fl) + 30 2(fl) +* 2H 2 0 U1 + 2S0 2(fl)
30 Calculate the standard enthalpy change (per mole) for the following reactions
Also write the equation for the reaction in each case
(a) Dissolving HC1 in water
(b) Combustion of C 4 H 10 vapor
(c) Combustion of liquid C 2 H 5 OH
(d) The production of PC1 5 from PC1 3
(e) The reaction of metallic zinc with dilute H 2 SO 4
31 The enthalpy of combustion of diamond is —94 50 kcal/mole The enthalpy of
combustion of graphite is -9405 kcal/mole What is the standard enthalpy
and entropy of transition from diamond to graphite
9
32 Calculate the standard enthalpy and entropy of vaporization of C 6 H 6 at
250°C
33 Calculate the bond energies in the following gaseous molecules (a) CO, (b)
CO 2 , (c) SO 2 , (d) NaCl The enthalpy of sublimation of NaCl is A// = +54 70
kcal/mole, and the standard enthalpy of formation of NaCl,,, is A//° = -98 23
kcal/mole
34 The observed heat of combustion at constant volume of a common fat,
glyceryl tnoleate (C 57 Hi 04 O 6(s) ) at 25 0°C is A£° = 7986 kcal/mole
(a) Write the equation for the combustion reaction and calculate A//° for the
reaction
(b) Calculate the standard enthalpy of formation of glyceryl tnoleate
(c) The overall metabolism of this fat in your body is the same as the combus
tion reaction in the bomb calorimeter Calculate how much heat is produced in your body for every ounce of this fat that you eat and metabolize
How much heat energy would your body produce while getting rid of one
pound of this fat
9