Name: _____________________________
1. ____ A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which
combination of these samples has the fastest reaction rate?
(1) a zinc strip and 1.0 M HCl(aq)
(3) zinc powder and 1.0 M HCl(aq)
(2) a zinc strip and 3.0 M HCl(aq)
(4) zinc powder and 3.0 M HCl(aq)
2. ____ For a given reaction, adding a catalyst increases the rate of the reaction by
(1) providing an alternate reaction pathway that has a higher activation energy
(2) providing an alternate reaction pathway that has a lower activation energy
(3) using the same reaction pathway and increasing the activation energy
(4) using the same reaction pathway and decreasing the activation energy
3. ____ Which reaction releases the greatest amount of energy per 2 moles of product?
(1) 2CO(g) + O2(g) →2CO2(g)
(2) 4Al(s) + 3O2(g) →2Al2O3(s)
(3) 2H2(g) + O2(g) →2H2O(g)
(4) N2(g) + 3H2(g)→2NH3(g)
4. ____ Which changes occur when Pt2+ is reduced?
(1) The Pt2+ gains electrons and its oxidation number increases.
(2) The Pt2+ gains electrons and its oxidation number decreases.
(3) The Pt2+ loses electrons and its oxidation number increases.
(4) The Pt2+ loses electrons and its oxidation number decreases.
Given the equation representing a reaction at equilibrium:
N2(g) + 3H2(g) ↔ 2NH3(g) + energy
5. ____ Which change causes the equilibrium to shift to the right?
(3) increasing the concentration of N2(g)
(1) decreasing the concentration of H2(g)
(2) decreasing the pressure
(4) increasing the temperature
6. Explain, in terms of collision theory, why the rate of a chemical reaction increases with an increase in temperature.
7.
On the diagram provided, draw a potential energy diagram for this
reaction.
8. Determine the total amount of energy released when 2.50 moles of
propane is completely reacted with oxygen.
Given the balanced equation representing a reaction:
H+(aq) + OH–(aq) ↔H2O(l) + 55.8 kJ
9. ____ In this reaction there is conservation of
(1) mass, only
(3) mass and energy, only
(2) mass and charge, only
(4) mass, charge, and energy
Regents Review – Reactions
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Created: April 2008
Name: _____________________________
10. ____ Which statement must be true when solution equilibrium occurs?
(1) The solution is at STP.
(2) The solution is supersaturated.
(3) The concentration of the solution remains constant.
(4) The masses of the dissolved solute and the undissolved solute are equal.
Given the balanced equation representing a reaction:
Cl2(g) ↔Cl(g) + Cl(g)
11. ____ What occurs during this change?
(1) Energy is absorbed and a bond is broken.
(2) Energy is absorbed and a bond is formed.
(3) Energy is released and a bond is broken.
(4) Energy is released and a bond is formed.
Given the balanced equation representing a reaction:
Zn(s) + 2HCl(aq) →H2(g) + ZnCl2(aq)
12. ____ Which set of reaction conditions produces H2(g) at the fastest rate?
(1) a 1.0-g lump of Zn(s) in 50. mL of 0.5 M HCl(aq) at 20.°C
(2) a 1.0-g lump of Zn(s) in 50. mL of 0.5 M HCl(aq) at 30.°C
(3) 1.0 g of powdered Zn(s) in 50. mL of 1.0 M HCl(aq) at 20.°C
(4) 1.0 g of powdered Zn(s) in 50. mL of 1.0 M HCl(aq) at 30.°C
Base your answers to questions 13 through 15 on the reaction represented by the balanced equation below.
2H2(g) + O2(g) ↔2H2O(l) + 571.6 kJ
13. Identify the information in this equation that indicates the reaction is exothermic.
14. On the axes provided, draw a potential energy diagram
for the reaction represented by this equation.
15. Explain why the entropy of the system decreases as the reaction proceeds.
Base your answers to questions 16 through 18 on the information below.
Rust on an automobile door contains Fe2O3(s). The balanced equation representing one of the reactions between iron in
the door of the automobile and oxygen in the atmosphere is given below.
4Fe(s) + 3O2(g) ↔2Fe2O3(s)
16. Identify the type of chemical reaction represented by this equation.
17. Determine the gram-formula mass of the product of this reaction.
18. Write the IUPAC name for Fe2O3.
19. ____ Which equation shows conservation of atoms?
(3) 2H2 + O2 →2H2O
(1) H2 + O2 →H2O
(4) 2H2 + 2O2 →2H2O
(2) H2 + O2 →2H2O
Given the equation representing a system at equilibrium:
20. ____ At which temperature does this equilibrium exist at 101.3 kilopascals?
(1) 0 K
(2) 0°C
(3) 32 K
(4) 273°C
Regents Review – Reactions
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Created: April 2008
Name: _____________________________
Base your answers to questions 21 and 22 on the information below.
The equilibrium equation below is related to the manufacture of a bleaching solution. In this equation, Cl–(aq) means that
chloride ions are surrounded by water molecules.
Cl2(g) + 2OH–(aq) ↔ OCl–(aq) + Cl–(aq) + H2O(l)
21. Use the key to draw two water molecules in the box,
showing the correct orientation of each water molecule toward
the chloride ion.
22. Explain, in terms of collision theory, why increasing the
concentration of Cl2(g) increases the concentration of OCl–
(aq) in this equilibrium system.
23. ____ Which term refers to the difference between the potential energy of the products and the potential energy of the
reactants for any chemical change?
(1) heat of deposition
(2) heat of fusion
(3) heat of reaction
(4) heat of vaporization
Given the balanced equation representing a reaction:
N2(g) + O2(g) + 182.6 kJ Æ 2NO(g)
On the labeled axes, draw a potential energy diagram for this reaction.
Base your answers to questions 14 and 25on the information below.
A beaker contains 100.0 milliliters of a dilute aqueous solution of ethanoic acid at
equilibrium. The equation below represents this system.
24. Compare the rate of the forward reaction to the rate of the reverse reaction for this system.
25. Describe what happens to the concentration of H+(aq) when 10 drops of concentrated HC2H3O2(aq) are added to this
system.
Base your answers to questions 26 through 28 on the information below.
“Hand Blasters” is a toy that consists of a set of two ceramic balls, each coated with a mixture of sulfur and potassium
chlorate, KClO3. When the two balls are struck together, a loud popping noise is produced as sulfur and potassium
chlorate react with each other.
26. Balance the equation for the “Hand Blaster” reaction, using the smallest whole-number coefficients.
27. Identify one source of the activation energy for this reaction.
28. Determine the oxidation number of chlorine in the reactant that contains chlorine.
Regents Review – Reactions
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Created: April 2008