- A quantity of 1.00×102 mL of 0.5 M HCl was mixed with 1.00×102 mL of 0.500 M NaOH in a constant-pressure calorimeter of negligible heat capacity. The initial temperature of the HCl and NaOH solution was the same, 22.5 oC, and the final temperature of the mixed solution was 25.86 oC. Calculate the heat change for the neutralization reaction on molar basis.
NaOH(aq) + HCl(aq) = NaCl(aq) + H2O (l)
Assume that the densities and specific heats of the solutions are the same as for water (1.00 g/mL and 4.184 J/g. oC, respectively).
- 2.18 kJ/mol
- -2.18 kJ/mol
- -56.2 kJ/mol
- 56.2 kJ/mol
- 280.3 kJ/mol
- Given the following data,
S(s) + O2(g) = SO2(g) ∆Ho(kJ/mol) = -395
S(g) + O2(g) = SO2(g) ∆Ho(kJ/mol) = -618
Find the heat required for the reaction converting solid sulfur S(s) to gaseous sulfur S(g) at 298 K and 1 atm pressure.
- -1406 kJ/mol
- -1264 kJ/mol
- -2670 kJ/mol
- +223 kJ/mol
- 142 kJ/mol
- From the following data ,
N2(g) + 3/2O2(g) = N2O3(s) ∆H = 83.7 kJ
N2(g) + O2(g) = 2NO(g) ∆H = 180.4 kJ
½ N2(g) + O2(g) = NO2(g) ∆H = 33.2 kJ
Calculate the enthalpy change ∆H for the reaction
N2O3(g) = NO(g) + NO2(g)
- -207.1 kJ
- -39.7 kJ
- 24.3 kJ
- 39.7 kJ
- 207.1 kJ
- Cerium is a common inorganic oxidant. Ce4+ reacts with Fe2+ as follows;
Ce4+ + Fe2+ = Ce3+ + Fe3+
The following initial rates at a given temperature were obtained for the concentration below:
Exp. [Ce4+] (M) [Fe2+] Initial Rate (M/s)
1 1.10 x10-5 1.80 x 10-5 2.00 x 10-7
2 1.10 x10-5 2.80 x 10-5 3.10 x 10-7
3 3.40 x10-5 2.80 x 10-5 9.50 x 10-7
The experimental rate law is
- rate = k[Ce4+]
- rate = k [Ce4+]1/2[Fe2+]
- rate = k [Ce4+][ Fe2+]1/2
- rate = k [Ce4+]2[Fe2+]
- rate = k [Ce4+ ][Fe2+]
- The rate constant k for the above reaction will be; (Answer from question 4)
- 1 M-1s-1
- 10 M-1s-1
- 101 M-1s-1
- 1010 M-1s-1
- 10101 M-1s-1
- What will be rate of reaction if [Ce4+] = 2.40 x10-5 M and [Fe2+] = 2.80 x 10-5?
(Answer from question 4)
- 9.80 x 10-7 M/s
- 6.80 x10-7 M/s
- 3.80 x 10-7 M/s
- 2.80 x 10-7 M/s
- 1.80 x 10-7 M/s
- A first-order chemical reaction is observed to have a rate constant of 35/min. What is the corresponding half-life of the reaction?
- 18 min
- 20 min
- 3.2 s
- 1.2 s
- 0.83 s
- For the reaction system
CoO(s) + H2(g) Co(s) + H2O(g)
at 550oC, K =67. The equilibrium constant expression is
- [CoO][H2]/[Co][H2O]
- [Co][H2O]/[CoO][H2]
- [Co][H2O]/[H2]
- [H2]/[H2O]
- [H2O]/[H2]
- For which reaction will Kc be equal to Kp?
a) H2O(g) ßà 2H(g) + O2(g)
b) H2(g) + S(s) ßà H2S(g)
c) 3H2(g) + N2(g) ßà 2NH3(g)
d) H2(g) + Br2(l) ßà 2HBr(g)
e) 2NO2(g) ßà N2O4(g)
- Consider the reaction;
SO2(g) + ½ O2(g) ßà SO3(g) Kc = 49 at 1000K
What is the value of Kc for the reaction below?
SO3(g) ßà 2SO2(g) + O2(g)
- 1/49
- 1/7
- 1/(49)2
- 7
- 49
- What is the pH of a 0.40 M ammonia NH3 solution if Kb is 1.8 x10-5?
- 12.42
- 1.30
- 11.43
- 2.42
- 5.94
- The oxidation of carbon monoxide proceeds as follows:
2CO(g) + O2(g) ↔ 2CO2(g) ∆Hro = -133.5 KJ
Which of the following will cause an increase in the equilibrium
concentration of CO?
- increasing the pressure of the system at constant temperature
- adding more O2 to the system
- removing CO2from the system as it is formed
- increasing the temperature of the system
- adding a catalyst
- Which of the following is a Lewis acid?
- I–
- NH3
- BCl3
- OH–
- CO2
- A solution which is formed by combining 300 mL of 0.020 M NaOH with 700 mL of 0.010 M HCl has a pH of
- 1.0
- 2.0
- 5.0
- 4.0
- 3.0
- All of the following have the free energy of formation value zero except
a) Br2(l) b) Fe(s) c) N(g) d) Na(s) e) Ne(g)
- 30 mL of 0.20 M NaOH are added to 30 mL of a 0.20 M CH3COOH. What is the pH of the resulting solution? ( Ka for CH3COOH is 1.8 x 10-5)
- 8.9
- 7.5
- 9.2
- 3.5
- 9.4
- For Cu(OH)2, Ksp = 2.6 x10-19. What is the molar solubility of Cu(OH)2?
- 6.4 x 10-7
- 2.7 x 10-11
- 5.1 x 10-10
- 1.7 x 10-10
- 4.0 x 10-7
- How many Faradays are required to convert a mole of Cr2O72- to Cr3+?
- 3 b) 4 c) 5 d) 6 e) 7
- Calculate the Eo for the cell reaction 2Cr + 3Sn4+ = 3Sn2+ + 2Cr3+
Cr3+ + 3e– = Cr Eo = -0.74 V
Sn4+ + 2e– = Sn2+ Eo = 0.15 V
- 1.93 V
- 0.89 V
- 0.59 V
- 0.45 V
- -0.59 V
- A weak acid (formic acid HCCOH) solution is titrated with strong base KOH solution. At the equivalence point;
- pH < 7.0
- pH = 7.0
- pH > 7.0
- pH = pKa
- the maximum buffering capacity is achieved
Answer Key:
- C 11. C
- D 12. D
- D 13. C
- E 14. E
- D 15. C
- B 16. A
- D 17. E
- E 18. D
- B 19. B
- C 20. C


