C4a Acids And Bases


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C4a Acids And Bases

  1. 1. C4a Acids and Bases neutral Acidic Basic (alkaline) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 strong weak neutral weak strong • Solutions with a pH of ________ than 7 are acids. • Solutions with a pH of ________ than 7 are alkalis/bases. • Solutions with a pH of 7 are_________________. HIGHER What is an acid? Look at the formulae of these acids. Hydrochloric acid HCl Sulphuric acid H2SO4 What element do they all have in common? Nitric acid HNO3 Phosphoric acid H3PO4 Definition: What is an alkali? Definition: What is the difference between an alkalis and a base? We often use the words base and alkali to describe the same chemicals. The difference is that an alkali is a base that _______________ in water. Alkalis – water soluble bases Bases s
  2. 2. Neutralisation • An acid can be neutralised by adding enough _____________ • An alkali can be neutralised by adding enough _____________ • Adding acid to alkali makes the pH go _________ • Adding alkali to acid makes the pH go _________ General equation for neutralisation: HIGHER Ionic equation for neutralisation: Uses of sulfuric acid: 1. 2. 3.
  3. 3. Making Salts Summary Everything on this page has been studied before but if it is not familiar you MUST learn it! Acids to Learn Hydrochloric acid HCl Sulphuric acid H2SO4 Nitric acid HNO3 Phosphoric acid H3PO4 Alkalis – water Salts soluble bases Compounds formed between a metal and the non-metal part of an acid in a neutralisation reaction Bases Acid Name of salt HCl chloride H2SO4 sulphate HNO3 nitrate H3PO4 phosphate metal + acid salt + hydrogen metal oxide + acid salt + water metal hydroxide + acid salt + water Metal carbonate + acid salt + water + carbon dioxide
  4. 4. Reacting acids with bases and carbonates The following are all of the names and symbols that the examiners can expect you to know. Any of these acids could react with any of the bases or carbonates in a neutralisation reaction Acids Bases Carbonates sulfuric acid potassium hydroxide sodium carbonate nitric acid sodium hydroxide calcium carbonate hydrochloric acid copper oxide ammonia Acids Bases Carbonates H2SO4 KOH Na2CO3 HNO3 NaOH CaCO3 HCl CuO NH3 Reactions with Sulfuric Acid Don’t forget state symbols: (aq) (g) (s) (l) sulfuric acid + potassium hydroxide + water H2SO4 (aq) + KOH(aq) + H2O(l) sulfuric acid + sodium hydroxide + water H2SO4 (aq) + NaOH (aq) + H2O(l) sulfuric acid + copper (II) oxide + water H2SO4 (aq) + CuO(s) + H2O(l) sulfuric acid + ammonia H2SO4 (aq) + NH3(aq) sulfuric acid + sodium carbonate + water + carbon dioxide H2SO4 (aq) + Na2CO3 (s) + H2O(l) + CO2 (g) sulfuric acid + calcium carbonate + water + carbon dioxide H2SO4 (aq) + CaCO3 (s) + H2O(l) + CO2 (g)
  5. 5. Do yo bes ur Reactions with Hydrochloric Acid t, d on’t pan Hydrochloric acid + potassium hydroxide ic! HCl(aq) + KOH (aq) Hydrochloric acid + sodium hydroxide HCl(aq) + NaOH (aq) Hydrochloric acid + copper (II) oxide HCl(aq) + CuO (s) Hydrochloric acid + ammonia HCl(aq) + NH3(aq) Hydrochloric acid + sodium carbonate HCl(aq) + Na2CO3 (s) Hydrochloric acid + calcium carbonate HCl(aq) + CaCO3 (s) Reactions with Sulfuric Acid nitric acid + potassium hydroxide nitric acid + sodium hydroxide nitric acid + copper (II) oxide nitric acid + ammonia nitric acid + sodium carbonate nitric acid + calcium carbonate If you got through that lot turn to your nearest neighbour and give them a well deserved high-5 !
  6. 6. small beaker Changing the pH small funnel dilute hydrochloric 1. Use a measuring cylinder to transfer acid burette clamp 30 cm3 of dilute sodium hydroxide solution to a 250 cm3 beaker. 2. Fill a burette with dilute hydrochloric acid as shown in the diagram. By turning the burette tap slightly check that the solution is able to drip out of the tap steadily. Close the tap and record the 100 cm3 beaker reading on the burette. (acting as a drip- tray) Volume of HCl added pH of solution Volume of HCl pH of solution from burette in conical flask added from burette in conical flask 0 15.5 0.5 16.0 1.0 16.5 1.5 17.0 2.0 17.5 2.5 18.0 3.0 18.5 3.5 19.0 4.0 19.5 4.5 20.0 5.0 20.5 5.5 21.0 6.0 21.5 6.5 22.0 7.0 22.5 7.5 23.0 8.0 23.5 8.5 24.0 9.0 24.5 9.5 25.0 10.0 25.5 10.5 26.0 11.0 26.5 11.5 27.0 12.0 27.5 12.5 28.0 13.0 28.5 13.5 29.0 14.0 29.5 14.5 30.0 15.0
  7. 7. Analysis of experiment 1. Describe how the pH changes over the course of the experiment as the acid is added to the alkali. 2. On the graph of your data mark the point on the curve where the pH is 7. What do you notice about the position of this point? 3. At what point on your graph is acid in excess? Explain your answer. (H) 4. The products of this neutralisation reaction are sodium chloride solution and water. Write a word equation for the reaction. 5. Write a symbol equation for the reaction. (H) 6. Suggest how the pH of a dilute solution of hydrochloric acid changes when a solution of sodium hydroxide is added to it until the sodium hydroxide is in excess. (H)