Reacting a Metal with an Acid info@ormalearn.com +254721524786 Home Chemistry Chemistry Form 1 Chemistry form 2 Resource center About us Contacts ☰ MENU ☰ Topics × Home Chemistry Chemistry Form 1 Chemistry form 2 Resource center About us Contacts × CHEMISTRY FORM 2 1. STRUCTURE OF THE ATOM, AND THE PERIODIC TABLE 1.1 Structure of the atom 1.2 Atomic Number and Mass Number 1.3 Isotopes 1.4 Energy levels and electron arrangement 1.5 Development of the Periodic Table 1.6 Relative Atomic Mass and Isotopes 1.7 Ion Formation 1.8 Chemical Formulae 1.9 Chemical Equations 2. CHEMICAL FAMILIES AND PATTERNS IN PROPERTIES 2.1 Alkali metals (Group I elements) 2.2 Alkali Earth Metals (Group II elements) 2.3 Halogens (Group VII elements) 2.4 Noble gases (Group VIII elements) 2.5 Properties and Trends Across the Periodic Table 3. CHEMICAL BONDING AND STRUCTURE 3.1 Bond 3.2 Ionic bond 3.3 Giant ionic structure 3.4 Covalent bond 3.5 Co-ordinate bond 3.6 Molecular structures 3.7 Giant covalent structures 3.8 Metallic Bond 3.9 Types of bond across a period 3.10 Oxides of elements in Period 3 3.11 Chlorides of Period 3 elements 4. SALTS 4.1 What is a salt? 4.2 Types of salt 4.3 Solubility of salts in water 4.4 Methods of preparing salts 4.4.1 Reacting a Metal with an Acid 4.4.2 Reacting an Acid with a Base (Neutralization) 4.4.3 Reacting an Acid with a Carbonate (or hydrogencarbonate of metal) 4.4.4 Combining elements Directly (Direct Combination of elements) 4.4.5 Precipitation (Double decomposition) 4.5 Action of heat on salts 4.6 Uses of salts 5. EFFECT OF AN ELECTRIC CURRENT ON SUBSTANCES 5.1 Electrical conduction 5.2 Electrical conductivity of molten substances 5.3 Electrical conductivity of substances in aqueous state 5.4 Electrolysis 5.5 Applications of electrolysis 6. CARBON AND SOME OF ITS COMPOUNDS 6.1 Allotropes of carbon 6.2 Chemical properties of carbon 6.3 Carbon (IV) oxide 6.4 Carbon (II) oxide (CO) 6.5 Large scale production of sodium carbonate and sodium hydrogencarbonate 6.6 Effect of carbon (II) oxide and carbon (IV) oxide on the environment 6.7 Carbon cycle Content developer Salts: Reacting a Metal with an Acid 4.0 Salts 4.4.1 Reacting a Metal with an Acid The choice of metal and acid depends on the salt we want to make. Which salt do you want: iron (II) sulphate (used in iron tablets), or zinc sulphate (medicine for zinc deficiency in humans)? Suppose we pick zinc sulphate. Questions 4.4.1(a) Which metal should we use to prepare zinc sulphate? Which acid is required to make this salt? The salt produced is soluble; so it will be in solution. Why are we certain of this, without testing? Write a balanced chemical equation for the reaction. How can we proceed to obtain crystals of zinc sulphate from the solution? Why is it not advisable to prepare sodium sulphate (or potassium sulphate) in a similar manner although they also produce salts with acids? Magnesium also reacts with acids to produce salts. But the salt is not pure. Suggest a reason why the salt is not pure. Hint: What else does magnesium produce? Besides carefully handling apparatus and chemicals, explain any safety precaution we should take during the reaction. Answers to Questions 4.4.1(a) In this method, we need a metal and an acid that make up the salt we want. For example, if we want iron (II) chloride, we use iron metal and hydrochloric acid. For aluminium sulphate, we need aluminium metal and sulphuric acid, and so on. This method is suitable for metals that do not react with cold water but react with dilute acids. They are zinc, aluminium, lead, and iron which are above copper in the reactivity series. Caution: Care must be taken to avoid bare flame during the reaction because hydrogen gas is produced. This burns explosively and can cause accident. Observe the video on preparation of zinc sulphate crystals below . ( courtesy Youtube-C11 - Salts (Salts Preparation using Method 1) by Nick Ng ) Questions 4.4.1(b) Describe step-by-step how you would prepare the salt, zinc sulphate. Answers to Questions 4.4.1(b) The acid is warmed so that the reaction occurs faster. Warming is stopped before the metal is added to avoid presence of a flame during the reaction. A small excess of the metal is an indication that all the acid is used up; so it will not contaminate the salt made. A glass rod is used to stir the reacting mixture because it (glass) is unreactive. Soluble salts should not be washed after filtration because they would re-dissolve in water. Figure 4.4.1 shows zinc sulphate crystals produced by this method. Figure 4.4.1(a) Zinc sulphate crystals Questions 4.4.1(c) Describe how you would prepare iron (II) sulphate from iron metal dust and a suitable dilute acid. Include an equation for the reaction. Answers to Questions 4.4.1(c) Have you noticed that preparation of salts from metals and acids follows the same procedure? It makes work easier. Figure 4.4.1(b) shows the appearance of iron (II) sulphate. Figure 4.4.1(b) Iron (II) sulphate Due to reaction with oxygen of the air (oxidation), iron (II) sulphate slowly turns brown as it gets oxidized to iron (III) sulphate. PREVIOUS NEXT Facebook Twitter Youtube Home About Acknowledgement Terms of service Contacts Privacy policy Content developer copyright@ormalearn