IB Topics 5 & 15 Multiple Choice ... 1 IB Topics 5 & 15 Multiple Choice Practice 1. Which...
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IB Topics 5 & 15 Multiple Choice Practice 1. Which statement is correct for this reaction? Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g) ΔH = −26.6 kJ
A. 13.3 kJ are released for every mole of Fe produced. B. 26.6 kJ are absorbed for every mole of Fe produced. C. 53.2 kJ are released for every mole of Fe produced. D. 26.6 kJ are released for every mole of Fe produced.
2. The enthalpy changes for two reactions are given.
Br2 (l) + F2 (g) → 2BrF (g) ΔH = x kJ Br2 (l) + 3F2 (g) → 2BrF3 (g) ΔH = y kJ What is the enthalpy change for the following reaction? BrF (g) + F2 (g) → BrF3 (g) A. x – y B. –x + y
C. (–x + y)
D. (x – y) 3. What is the enthalpy change, in kJ, of the following reaction? 3H2 (g) + N2 (g) 2NH3 (g)
A. (6 × 391) − [(3 × 436) + 945] B. (3 × 391) − (436 + 945) C. −[(3 × 436) + 945] + (3 × 391) D. −(6 × 391) + [(3 × 436) + 945]
4. Which expression gives the mass, in g, of ethanol required to produce 683.5 kJ of heat upon complete combustion?
(Mr for ethanol = 46.0, )
D. 5. Which expression gives the enthalpy change, ΔH, for the thermal decomposition of calcium carbonate?
A. ΔH = ΔH1 − ΔH2 B. ΔH = 2ΔH1 − ΔH2 C. ΔH = ΔH1 − 2ΔH2 D. ΔH = ΔH1 + ΔH2
6. In which order does the oxygen–oxygen bond enthalpy increase? A. H2O2 < O2 < O3 B. H2O2 < O3 < O2 C. O2 < O3 < H2O2 D. O3 < H2O2 < O2
7. What can be deduced from this reaction profile?
A. The reactants are less stable than the products and the reaction is exothermic. B. The reactants are less stable than the products and the reaction is endothermic. C. The reactants are more stable than the products and the reaction is exothermic. D. The reactants are more stable than the products and the reaction is endothermic.
8. Why is the value of the enthalpy change of this reaction calculated from bond enthalpy data less accurate than that calculated from standard enthalpies of formation?
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) A. All the reactants and products are gases. B. Bond enthalpy data are average values for many compounds. C. Elements do not have standard enthalpy of formation. D. Standard enthalpies of formation are per mole.
9. What can be deduced from the facts that ozone absorbs UV radiation in the region of 340 nm and molecular oxygen in the region of 242 nm?
A. The bond between atoms in molecular oxygen is a double bond. B. The bonds in ozone are delocalized. C. The bonds between atoms in ozone are stronger than those in molecular oxygen. D. The bonds between atoms in molecular oxygen need more energy to break.
10. Which statements are correct for ionic compounds?
I. Lattice energy increases as ionic radii increase. II. Within the same group, the melting point of salts tends to decrease as the radius of the cation increases. III. Solubility in water depends on the relative magnitude of the lattice energy compared to the hydration energy. A. I and II only B. I and III only C. II and III only D. I, II and III
11. What is the standard enthalpy of formation, in kJ mol–1, of IF (g)?
IF7 (g) + I2 (s) → IF5 (g) + 2IF (g) ΔH = –89 kJ
ΔH (IF7) = –941 kJ mol–1
ΔH (IF5) = –840 kJ mol–1 A. –190 B. –95 C. +6 D. +95
12. The combustion of glucose is exothermic and occurs according to the following equation: C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g) Which is correct for this reaction?
13. Which equation represents the lattice enthalpy of magnesium sulfide?
A. MgS (s) → Mg (g) + S (g) B. MgS (s) → Mg+ (g) + S– (g) C. MgS (s) → Mg2+ (g) + S2– (g) D. MgS (s) → Mg (s) + S (s)
14. The enthalpy change for the dissolution of NH4NO3 is +26 kJ mol–1 at 25 °C. Which statement about this reaction is correct?
A. The reaction is exothermic and the solubility decreases at higher temperature. B. The reaction is exothermic and the solubility increases at higher temperature. C. The reaction is endothermic and the solubility decreases at higher temperature. D. The reaction is endothermic and the solubility increases at higher temperature.
15. Which equation represents enthalpy of hydration?
A. Na(g) → Na+(aq) + e− B. Na+(g) → Na+(aq) C. NaCl(s) → Na+(g) + Cl−(g) D. NaCl(s) → Na+(aq) + Cl−(aq)
16. Which combination of ΔH θ and ΔS θ will result in a non-spontaneous reaction at all temperatures?
17. Which ion’s hydration energy is the most exothermic?
A. Li+ B. Na+ C. Br– D. I–
18. The Born-Haber cycle for potassium oxide is shown below: Which expression represents the lattice enthalpy in kJ mol–1? A. –361 + 428 + 838 + 612 B. –(–361) + 428 + 838 + 612 C. –361 + 428 + 838 – 612 D. –(–361) + 428 + 838 – 612
19. Which change of state is exothermic?
A. CO2(s) → CO2(g) B. H2O(l) → H2O(g) C. NH3(g) → NH3(l) D. Fe(s) → Fe(l)
20. The C=N bond has a bond length of 130 pm and an average bond enthalpy of 615kJmol-1. Which values would be most likely for the C-N bond?
21. When 25.0cm3 0.100moldm−3 NaOH(aq) is mixed with 25.0cm3 0.100moldm−3 HCl(aq) at the same temperature, a temperature rise, ∆T, is recorded. What is the expression, in kJ mol−1, for the enthalpy of neutralisation? (Assume the density of the mixture = 1.00 g cm−3 and its specific heat capacity=4.18kJkg−1K−1 =4.18Jg−1K−1)
D. 22. Hydrazine reacts with oxygen. N2H4(l) + O2(g) → N2(g) + 2H2O(l) ΔHθ = -623 kJ
What is the standard enthalpy of formation of N2H4(l) in kJ? The standard enthalpy of formation of H2O(l) is -286 kJ. A. -623 - 286 B. -623 + 572 C. -572 + 623 D. -286 + 623
23. What is the enthalpy of formation of ethyne, in kJmol−1, represented by the arrow Y on the diagram?
A. −788−286+1301 B. −788−286−1301 C. +788+286−1301 D. +788+286+1301
24. In which reaction do the reactants have a lower potential energy than the products? A. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) B. HBr(g) → H(g) + Br(g) C. Na+(g) + Cl-(g) → NaCl(s) D. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
25. Which equation represents the average bond enthalpy of the Si−H bond in SiH4?
B. SiH4 (g) → Si(g) + H(g)
C. SiH4(g) → SiH3(g) + H2(g) D. SiH4 (g) → Si(g) + 4H(g)
26. 5.35g of solid ammonium chloride, NH4Cl(s), was added to water to form 25.0g of solution. The maximum decrease in temperature was 14 K. What is the enthalpy change, in kJmol-1, for this reaction? (Molar mass of NH4Cl = 53.5gmol-1; the specific heat capacity of the solution is 4.18 Jg-1K-1)
D. 27. The equation for the formation of ethyne is: 2C(s) + H2 (g) → C2H2 (g)
What is the enthalpy change, in kJ, for this reaction using the enthalpy of combustion data below?
A. 2 × (−394) + (−572) − (−2602) B. 2 × (−394) + (−572) − (−2602)
C. 2 × (−394) + (−572) + (−2602) D. 2 × (−394) + (−572) + (−2602)
28. Which transition represents an enthalpy of hydration?
A. 2H2O (l) → H3O+ (aq) + OH− (aq) B. NaCl (s) → Na+ (aq) + Cl− (aq) C. K+(s)→K+(aq) D. K+(g)→K+(aq)
29. Which represents the enthalpy change of hydration of the chloride ion?
30. What are the signs for the entropy changes associated with this reaction? H2O(g) → H2O(l)
31. Which ionic compound has the largest value of lattice enthalpy?
A. MgS B. MgO C. CaBr2 D. NaF
32. Which processes are exothermic?
III. A. I and II only B. I and III only C. II and III only D. I, II and III
33. Which equation corresponds to the bond enthalpy of the H–I bond?
D. 34. Which combination is correct for the standard enthalpy change of neutralization?
35. When four moles of aluminium and four moles of iron combine with oxygen to form their oxides, the enthalpy changes are –3338 kJ and –1644 kJ respectively.
What is the enthalpy change, in kJ, for the reduction of one mole of iron(III) oxide by aluminium?
A. B. C. D.
36. Which enthalpy changes can be calculated using only bond enthalpy data?
III. A. I and II only B. I and III only C. II and III only D. I, II and III
37. The same amount of heat energy is added to 1.00 g of each substance.
Which statement is correct if all the substances are at the same temperature before the heat energy is added? A. Copper will reach the highest temperature. B. Water will reach the highest temperature. C. All four substances will reach the same temperature. D. Aluminium will reach a higher temperature than sodium chloride.
38. Which equation represents the standard enthalpy of formation of liquid methanol?
D. 39. Which species are arranged in order of increasing entropy?
40. Which combination of and values corresponds to a non-spont