Chemical Changes and Structure Acids, Bases and pH NAT 5 Homework One 1. Which of the following oxides will dissolve in water to produce an alkaline solution? (You may wish to use page 8 of the data booklet to help you.) A Carbon dioxide B Copper(II) oxide C Potassium oxide D Nitrogen dioxide (1) 2. Which of the following oxides, when shaken with water, would leave the pH unchanged? (You may wish to use page 8 of the data booklet to help you.) A Carbon dioxide B Copper oxide C Sodium oxide D Sulfur dioxide (1) 3. Which of the following oxides, when shaken with water, would give an acidic solution? A Calcium oxide B Nickel oxide C Lithium oxide D Sulfur dioxide (1) 4. What is the most likely pH value that would be obtained when zinc oxide is added to water? (You may wish to use page 8 of the data booklet to help you.) A 5 B 7 C 9 D 11 (1) 5. Copy and complete the following: The pH scale is a __________ range. ___________ have a pH of less than 7 and ________ have a pH of more than 7. Neutral solutions have a pH equal to __. (2) 6. Slaked lime can be added to lochs to reduce acidity. (a) What causes the lochs to become acidic? (1) Slaked lime can be made from limestone. (1) (b) Name the elements present in calcium carbonate. (c) Suggest a name for chemical X. (1) 7. If hydrogen sulfide is not removed before methane gas is burned, sulfur dioxide is formed. (a) Complete the sentence When sulfur dioxide dissolves in water in the atmosphere, ____ rain is produced. (1) (b) In industry, calcium oxide is reacted with sulfur dioxide to reduce the volume of sulfur dioxide released into the atmosphere. Explain why calcium oxide is able to reduce the volume of sulfur dioxide gas released. (2) 8. Antacid tablets are used to treat indigestion which is caused by excess acid in the stomach. Different brands of tablets contain different active ingredients. (a) Write the formula for aluminium hydroxide. (1) (b) (i) Complete the table to show the cost of using magnesium carbonate to (1) neutralise 20 cm3 of acid. (ii) Which one of the four active ingredients would you use to neutralise excess (1) stomach acid? Explain your choice. .