Ch.5 Classification & Balancing of Chemical Reactions
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Problem 8
Identify the oxidized reactant, the reduced reactant, the oxidizing agent, and the reducing agent in the following reactions: a. Fe(s)+Cu₂+(aq) → Fe₂+(aq)+Cu(s) b. Mg(s)+Cl₂(g) → MgCl₂(s) c. 2 Al(s)+Cr₂O₃(s) → 2 Cr(s) + Al₂O₃(s)Problem 9
Potassium, a silvery metal, reacts with bromine, a corrosive, reddish liquid, to yield potassium bromide, a white solid. Write the balanced equation, and identify the oxidizing and reducing agents.Problem 16
Assume that the mixture of substances in drawing (a) undergoes a reaction. Which of the drawings (b)–(d) represent a product mixture consistent with the law of conservation of mass? a.
b.
c.
d.Problem 17
Reaction of A (green spheres) with B (blue spheres) is shown in the following diagram:
Which equation best describes the reaction? a. A₂ + 2 B → A₂B₂ b. 10 A + 5 B₂ → 5 A₂B₂ c. 2 A + B₂ → A₂B₂ d. 5 A + 5 B₂ → 5 A₂B₂
Problem 20
An aqueous solution of a cation (represented as blue spheres in the diagram) is allowed to mix with a solution of an anion (represented as green spheres) and the following result is obtained:
Which combinations of cation and anion, chosen from the following lists, are compatible with the observed results? Explain. Cations: Na+, Ca2+, Ag+, Ni2+ Anions: Cl−, CO2−3, CrO2−4, NO−3
Problem 22
What is meant by the term 'balanced equation'?Problem 23
Why is it not possible to balance an equation by changing the subscript on a substance, say from H₂O to H₂O₂?Problem 27
Which of the following equations are balanced? Balance those that need it. a. CaC₂+2 H₂O→Ca(OH)₂+C₂H₂ b. C₂H₈N₂+2 N₂O₄→2 N₂+2 CO₂+4 H₂O c. 3 MgO +2 Fe→Fe₂O₃+3 Mg d. N₂O→N₂+O₂Problem 44
When sodium metal is placed in water, the following change occurs: Sodium, Na (s) + Water, H2O (l) → Hydrogen, H₂ (g) + Sodium hydroxide, NaOH (aq) a. Identify the reactants and products and their physical statesProblem 49
In each of the following, tell whether the substance gains electrons or loses electrons in a redox reaction: a. An oxidizing agent b. A reducing agent c. A substance undergoing oxidation d. A substance undergoing reductionProblem 73
High temperature combustion processes, such as in combustion engines and coal-fired power plants, can result in the reaction of nitrogen and sulfur with oxygen to form nitrogen oxides (NO𝓍) and sulfur oxides (SO𝓍), where x can vary. These NO𝓍 and SO𝓍 compounds subsequently undergo further reaction in the atmosphere to create acidic compounds that contribute to acid rain. a. Do some research to determine the common products that are formed (i.e., what are the values of x) for the reactions of N and S with oxygen. Write balanced equations for these reactions.Problem 75
Many pharmaceuticals are marketed with the designation 'HCl' appended to the name of the drug. What does the 'HCl' mean? What type of reaction would be involved in converting a drug to the HCl form? What are the advantages of this form of the drug?Problem 93
Cobalt(II) chloride, a blue solid, can absorb water from the air to form cobalt(II) chloride hexahydrate, a pink solid. The equilibrium is so sensitive to moisture in the air that CoCl₂ is used as a humidity indicator. Write a balanced equation for the equilibrium. Be sure to include water as a reactant to produce the hexahydrate.
