Grade 11 Chemistry - Chapter 10 Acids and Bases

Grade 11 Chemistry – Chapter 10 Acids and Bases Test Review Sheet 10.1 Properties of Acids and Bases: Summary: Acids and bases have characteristic physical and chemical properties. According to Arrhenius, acids produce hydrogen ions (H?) in aqueous solution, while bases produce hydroxide ions (OH?). Acids have pH values less than 7, taste sour, react with active metals to produce hydrogen gas, and react with carbonates to form carbon dioxide. Bases have pH values greater than 7, feel slippery, taste bitter, and neutralize acids. Both acids and bases conduct electricity in solution and can be identified using acid–base indicators. Review Questions: 1. (2 marks) Identify two chemical properties that distinguish acids from bases and provide one example reaction for each. 2. (3 marks) Write a balanced chemical equation showing the reaction between hydrochloric acid and magnesium metal. Identify the gas produced. 3. (4 marks) Explain why acids react with carbonate compounds to produce carbon dioxide gas. Include a balanced chemical equation. 4. (5 marks) Name the following acids or bases and justify your answers: HCl(aq), H?SO?(aq), NaOH(aq), Ca(OH)?(aq). 5. (4 marks) Explain why tooth enamel can be damaged by acidic foods and beverages using chemical reasoning. 10.2 Theoretical Acid–Base Definitions: Summary: Several theories have been developed to explain acid–base behavior. The Arrhenius theory, proposed by Svante Arrhenius, defines acids as substances that ionize in water to produce H? ions and bases as substances that dissociate to produce OH? ions. Neutralization reactions occur when acids and bases react to form water. Acids can be classified as strong or weak based on the extent of ionization in solution. The pH scale is logarithmic, meaning each change of one pH unit represents a tenfold change in acidity. Review Questions: 1. (2 marks) State the Arrhenius definition of an acid and a base. Name the scientist associated with this theory. 2. (3 marks) Explain the difference between ionization and dissociation, using one example of each. 3. (4 marks) Compare a strong acid and a weak acid of the same concentration in terms of ionization and pH. 4. (5 marks) A solution has a pH of 3. Another solution has a pH of 6. How many times more acidic is the first solution? Show your reasoning. 5. (4 marks) Write the total ionic and net ionic equations for the neutralization of nitric acid with sodium hydroxide. 10.3 Acid–Base Stoichiometry: Summary: Acid–base stoichiometry involves quantitative analysis of neutralization reactions. Titration is a laboratory technique used to determine the concentration of an unknown solution using a standardized solution. The equivalence point occurs when the moles of H? equal the moles of OH?, while the endpoint is identified by an indicator color change. Stoichiometric calculations require a balanced chemical equation, mole ratios, and proper unit conversions. Review Questions: 1. (3 marks) Define titration and explain the purpose of an acid–base indicator. 2. (4 marks) Distinguish between the equivalence point and the endpoint in a titration. 3. (5 marks) Calculate the concentration of a sodium hydroxide solution if 25.00 mL of it is neutralized by 18.50 mL of 0.100 mol/L HCl. Show all steps. 4. (5 marks) Write the balanced chemical equation for the titration of sulfuric acid with potassium hydroxide and explain the mole ratio used. 5. (5 marks) A 10.00 mL sample of an unknown acid is titrated with 0.200 mol/L NaOH. If 22.40 mL of base is required to reach the endpoint, calculate the concentration of the acid.