ACSBR Acids and Bases - Assignment

Anglo-Chinese School (Barker Road) A Methodist Institution Founded in 1886 CHEMISTRY DEPARTMENT OF SCIENCE Name: ( ) Class: SEC 3 ACIDS & BASES – ASSIGNMENT ALEX LEE/2010 PAGE 1 OF 5 PURE/COMBINED Multiple-Choice Questions [20 Marks] TOTAL SCORE / 30 Write in your selected answer for the multiple-choice questions in the boxes provided. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1. A 50 cm3 sample of acid was placed in a beaker, and universal indicator was added. Aqueous alkali was then added gradually, and the pH of the solution measured at regular intervals. Below shows the graph of the resulting pH against volume of sodium hydroxide added. 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 6010203040500 volume of NaOH(cm3) pH 700.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 6010203040500 volume of NaOH(cm3) pH 70 What is the volume of aqueous sodium hydroxide required to neutralise the acid sample? A 10 cm3 B 28 cm3 C 50 cm3 D 60 cm3 2. Which one of the following statements is the most accurate definition of an acid? A An acid is a substance that liberates carbon dioxide when added to a carbonate. B An acid is a substance that produces hydrogen ions in aqueous solution. C An acid is a substances that turns blue litmus solution red D An acid is a substance that reacts with a base.

ALEX LEE/2010 PAGE 2 OF 5 3. The pH of several household substances is shown below: Substance green tea kitchen cleaner polish remover vinegar pH 7.9 9.9 6.5 5.1 Which of the above substances would most likely produce a blue and yellow colour respectively when tested with universal indicator? blue yellow A green tea polish remover B kitchen cleaner green tea C polish remover vinegar D vinegar kitchen cleaner 4. Which of the following is not a property of an acid? A Acids are soluble in water. C Acids have a sour taste. B Acids dissociate hydrogen molecules. D Acids turn litmus solution red. 5. Which one of the following must be true of an acidic gas? A It is the only salt formed from a dibasic acid. B It has dissociated hydrogen ions. C It turns damp universal indicator paper orange. D It turns dry blue litmus paper red. 6. Which of the following is not a similarity between ethanoic acid and hydrochloric acid? Both acids are A monobasic acids. C weak acids. B of a pH less than 7. D able to react with insoluble bases. 7. Citric acid, found in oranges, is a weak acid because it A is used in food products. C is not completely ionised in solution. B is not very soluble in water. D freezes on a cold day. 8. The pH of four aqueous solutions P, Q, R and S, is as shown in the diagram below. Which of the following sets of substances correctly corresponds with the pH of solutions P, Q, R & S (in this order)? A sulfuric acid; ethanoic acid; sodium chloride; aqueous ammonia B aqueous ammonia, sodium chloride; ethanoic acid; sulfuric acid C ethanoic acid; sulfuric acid; sodium chloride; aqueous ammonia D sulfuric acid; ethanoic acid; aqueous ammonia, sodium chloride P Q R S pH 1.0 pH 7.0 pH 13.0

ALEX LEE/2010 PAGE 3 OF 5 9. Carbonic acid, H2CO3, is considered to be dibasic because A Each molecule of carbonic acid is able to react with two hydroxide ions. B It contains twice the concentration of hydrogen ions compared to hydrochloric acid. C It has two hydrogen atoms in its molecular structure before dissociation. D The pH of carbonic acid is half that of a regular monobasic acid. 10. Jonathan places mixes a small sample of aqueous sodium hydroxide with another small sample of ammonium sulfate in a test tube, and warms the mixture gently over a bunsen burner. sodium hydroxide + ammonium sulfate ⎯→ salt X + gas Y + liquid Z What would be the salt X produced in this reaction? A sulfuric acid C ammonium hydroxide B aqueous ammonia D sodium sulfate 11. Which of the following best describes this reaction: NaOH (aq) + HNO3 (aq) ⎯→ NaNO3 (aq) + H2O (l) A titration reaction C nitrate reaction B water-producing reaction D neutralization reaction 12. Which two substances will react together to form water and a salt as the only products? A dilute nitric acid + aqueous sodium carbonate B aqueous barium chloride + aqueous sodium carbonate C dilute sulfuric acid + zinc D dilute sodium hydroxide + dilute phosphoric acid 13. Which of the following pairs of chemicals, when mixed, will produce salt, gas and water? A sulfuric acid + magnesium metal C nitric acid + sodium hydroxide B hydrochloric acid + calcium carbonate D carbonic acid + ammonium chloride 14. Powdered zinc carbonate is added to a solution of sulfuric acid until effervescence ceases. The pH of the solution A decreases to about 7. C increases to about 12. B increases to about 7. D decreases to about 3. 15. Which of the following correctly shows the ionic equation for the formation of sodium chloride from dilute hydrochloric acid and aqueous sodium hydroxide? A 2 Na+ (aq) + Cl2 (aq) ⎯→ 2 NaCl (s) B H+ (aq) + NaOH (aq) ⎯→ Na+ (aq) + H2O (l) C H+ (aq) + OH- (aq) ⎯→ H2O (l) D Na+ (aq) + Cl- (aq) ⎯→ NaCl (s)

ALEX LEE/2010 PAGE 4 OF 5 16. Below shows some reactions of copper compounds. Which change is made by adding an acid? 17. Which one of the following elements forms a neutral oxide? A carbon B zinc C sulfur D copper 18. Which of the following sets of oxides contain one acidic oxide, one basic oxide, and one amphoteric oxide (not necessarily in order)? A calcium oxide; magnesium oxide; sulfur dioxide B calcium oxide; sulfur dioxide; zinc oxide C aluminium oxide; carbon dioxide; carbon monoxide D aluminium oxide; magnesium oxide; zinc oxide 19. A man suffering from an excess of acid in his stomach has no indigestion tablets. Which substance could he now take to lower this acidity? A lemon juice B salt water C vinegar D baking soda 20. Which of the following substances is most commonly added to increase the pH of soil? A Ca(OH)2 (s) B CH3COOH (aq) C NaOH (aq) D ZnO (s) copper(II) sulfate CuSO4 malachite CuCO3 copper(II) oxide CuO copper Cu A B C D

ALEX LEE/2010 PAGE 5 OF 5 Structured Questions [10 Marks] 21. Ammonium carbonate, due to the presence of both carbonate ions and ammonium ions, is able to behave as a metal carbonate and also as an ammonium salt. It is hence able to react, separately, with both acids and alkalis, producing different products. (a) A sample of aqueous ammonium carbonate is allowed to react with dilute sulfuric acid. (i) Construct the chemical equation, with state symbols, for the reaction. [2] (ii) Construct the ionic equation for the reaction. [1] (b) A separate sample is then allowed to react with aqueous sodium hydroxide. (i) Construct the chemical equation, with state symbols, for the reaction. [2] (ii) Construct the ionic equation for the reaction. [1] 22. Construct chemical equations for (a) the reaction between iron(III) oxide and sulfuric acid, [1] (b) the reaction between ammonium chloride and calcium hydroxide. [1] 23. Construct ionic equations for the following reactions. (a) Mg (s) + 2 HCl (aq) ⎯→ MgCl2 (aq) + H2 (g) [1] (b) (NH4)2SO4 (aq) + 2 LiOH (aq) ⎯→ Li2SO4 (aq) + 2 H2O (l) + 2 NH3 (g) [1] END