Presentation is loading. Please wait.

Presentation is loading. Please wait.

© Boardworks Ltd 20071 of 55. 2 of 55© Boardworks Ltd 2007  + acidbasea salt How are salts made and named? When an acid reacts with a base, a neutralization.

Similar presentations


Presentation on theme: "© Boardworks Ltd 20071 of 55. 2 of 55© Boardworks Ltd 2007  + acidbasea salt How are salts made and named? When an acid reacts with a base, a neutralization."— Presentation transcript:

1 © Boardworks Ltd 20071 of 55

2 2 of 55© Boardworks Ltd 2007  + acidbasea salt How are salts made and named? When an acid reacts with a base, a neutralization reaction occurs and produces a chemical called a salt. The name of the salt depends on the names of the reactants. The first part of the salt’s name comes from the base: e.g. sodium hydroxide sodium…  The second part of the salt’s name comes from the acid: e.g. sulfuric acid sulfate…  For example, if sodium hydroxide neutralizes sulfuric acid, the product is a salt called sodium sulfate.

3 3 of 55© Boardworks Ltd 2007 What is the name of the salt?

4 4 of 55© Boardworks Ltd 2007 What are salts used for? Table salt is sodium chloride. This is the salt used to flavour and preserve food. Indigestion remedies often contain magnesium salts. Salts can also be used as coloured pigments in paints, and to help fuels burn better. The colours of fireworks are formed when certain salts burn. Calcium chloride, for example, burns a bright red colour.

5 5 of 55© Boardworks Ltd 2007 Water is formed because OH – ions from the alkali react with H + ions from the acid to produce molecules of water (H 2 O). Making salts 1: acid + alkali When an acid reacts with an alkali, the products are a salt and water. acidalkalisaltwater +  + For example: ++  ++  sodium hydroxide NaOH (aq) sodium chloride NaCl (aq) water H 2 O (aq) hydrochloric acid HCl (aq)

6 6 of 55© Boardworks Ltd 2007 When is the reaction complete? There is no obvious sign when this reaction is complete, so an indicator is used to show when the solution is neutral. This process is called titration. The reaction between sodium hydroxide and hydrochloric acid produces sodium chloride, which is soluble in water. ++  ++  sodium hydroxide NaOH (aq) sodium chloride NaCl (aq) water H 2 O (aq) hydrochloric acid HCl (aq)

7 7 of 55© Boardworks Ltd 2007 What is a titration?

8 8 of 55© Boardworks Ltd 2007 Making salts 2: acid + metal When a metal is added to an acid, the products are a salt and hydrogen gas. For example: This method of making salts only works with some metals. hydrochloric acid 2HCl (aq) +  + + +  zinc Zn (aq) zinc chloride ZnCl 2 (aq) hydrogen H 2 (aq) acidmetala salthydrogen +  + What would happen if potassium was used? Or copper?

9 9 of 55© Boardworks Ltd 2007 Which metal will react the most?

10 10 of 55© Boardworks Ltd 2007 Making salts 3: acid + metal oxide When a metal oxide is mixed with an acid, the products are a salt and water. calcium chloride +  water calcium oxide CaO (aq) hydrochloric acid 2HCl (aq) CaCl 2 (aq) + + +  H 2 O (aq) For example: acidmetal oxidesaltwater +  + Water forms because oxygen ions from the oxide join up with H + ions from the acid to produce molecules of water (H 2 O).

11 11 of 55© Boardworks Ltd 2007 Obtaining salts from metal oxides When a metal oxide is added to an acid, it dissolves as it reacts. How could the solid copper sulfate salt be separated from the water? You know when you have added enough of the metal oxide because it stops dissolving. ++  copper oxide CuO (s) sulfuric acid H 2 SO 4 (aq) copper sulfate CuSO 4 (aq) water H 2 O (aq)

12 12 of 55© Boardworks Ltd 2007 Obtaining salts from copper oxide

13 13 of 55© Boardworks Ltd 2007 Making salts 4: acid + carbonate When a carbonate is mixed with an acid, the products are a salt, carbon dioxide and water. copper nitrate +  water + carbon dioxide copper carbonate CuCO 3 (s) nitric acid 2HNO 3 (aq) Cu(NO 3 ) 2 (aq) + + +  H 2 O (aq) + CO 2 (g) For example: What would you expect to observe in this reaction? acidcarbonatesaltwater +  + carbon dioxide + Water and carbon dioxide are formed because the carbonate ions (CO 3 2- ) react with H + ions from the acid.

14 14 of 55© Boardworks Ltd 2007 Making salts – summary Salts can be made by reacting acids with bases. acid + alkalia salt + water acid + metala salt + hydrogen acid + metal oxidea salt + water acid + carbonatea salt + carbon dioxide + water     There are four ways of making salts from acids:

15 15 of 55© Boardworks Ltd 2007 Matching reactants and salts

16 16 of 55© Boardworks Ltd 2007 Complete the neutralization reaction

17 © Boardworks Ltd 200717 of 55

18 18 of 55© Boardworks Ltd 2007 Sometimes when two solutions are mixed, they react to form an insoluble solid product. For example, mixing solutions of lead nitrate and sodium chloride produces a yellow precipitate of lead chloride. What is a precipitation reaction? The insoluble solid product is called a precipitate. You can spot a precipitate because the mixture goes cloudy. lead nitrate Pb(NO 3 ) 2 (aq) sodium chloride 2NaCl (aq) lead chloride PbCl 2 (s) sodium nitrate 2NaNO 3 (aq)   + + + +

19 19 of 55© Boardworks Ltd 2007 How can hard water be softened? Hard water contains magnesium and calcium ions, which can clog up pipes and heating elements. These ions can be removed using precipitation reactions. The magnesium ions are removed by this reaction: What are the word and symbol equations for the removal of the calcium ions? Sodium carbonate is added to the hard water to form precipitates, which can then be removed by filtration. sodium carbonate Na 2 CO 3 (aq) magnesium chloride MgCl 2 (aq) sodium chloride 2NaCl (aq) magnesium carbonate MgCO 3 (s) +  + +  +

20 20 of 55© Boardworks Ltd 2007 Many metals form hydroxide precipitates, which have characteristic colours. Precipitates of hydoxides For example, when sodium hydroxide solution is added to a solution of iron(III) chloride, the reaction produces a brown precipitate of iron(III) hydroxide. ++  FeCl 3 (aq)3NaOH (aq)Fe(OH) 3 (s) ++  3NaCl (aq) iron(III) chloride sodium hydroxide iron(III) hydroxide sodium chloride

21 21 of 55© Boardworks Ltd 2007 Identifying precipitates

22 22 of 55© Boardworks Ltd 2007 Identifying metals

23 23 of 55© Boardworks Ltd 2007 Precipitation – true or false?

24 © Boardworks Ltd 200724 of 55

25 25 of 55© Boardworks Ltd 2007 Glossary acid – A substance that releases H + ions in solution. alkali – A substance that releases OH - ions in solution. base – Any substance that reacts with an acid. decomposition – A type of reaction in which a compound is broken down into two or more substances. neutralization – A type of reaction in which an acid reacts with a base to produce a salt. precipitate – A solid, insoluble product of a reaction. precipitation – A type of reaction in which two aqueous solutions react to form an insoluble product. salt – A substance formed when an acid reacts with a base. titration – A method of indicating when an undetectable reaction, such as neutralization, is complete.

26 26 of 55© Boardworks Ltd 2007 Anagrams

27 27 of 55© Boardworks Ltd 2007 Completing equations

28 28 of 55© Boardworks Ltd 2007 Multiple-choice quiz


Download ppt "© Boardworks Ltd 20071 of 55. 2 of 55© Boardworks Ltd 2007  + acidbasea salt How are salts made and named? When an acid reacts with a base, a neutralization."

Similar presentations


Ads by Google