Reaction of metal with oxygen

all rection of metal presented in this ppt

1. Welcome to the science presentation of Formative Assessment-3 The topic we are going to discuss now is

2. Metals and Non-metals

3. Group Members Chirag jain Sanyam jain Risahbh Deepanshu Akshay Tushant Uttkarsh Swarndeep Gaurav

4. physical properties of metals ...

5. 1. Metals are malleable , that is , metals can be beaten into thin sheets with a hammer . 2. Metals are ductile , that is , metals can be drawn into thin wires. 3. Metals are good conductors of heat . 4. Metals are lustrous and can be polished . 5. Metals are good conductors of electricity . 6. Metals are sonorous . 7. Metals have high densities .

6. Chemical Reaction of metals Reaction of metal with oxygen Almost all metal combing with oxygen to from metal. For example:- Copper (Cu) reacts with oxygen to from copper ( ll ) oxide , a black oxide. 2Cu + O₂ 2CuO Metal + Oxygen Metal oxide

7. Aluminium (Al) reacts with oxygen to from aluminium Oxide. 4Al + 3O₂ 2Al₂O₃ Sodium reacts with oxygen at room temprature to from sodium oxide . 4Na + O₂ 2Na₂O Magnesium does not react with oxygen at room temprature . On heating in oxygen , magnesium burns with dazzling white light to give magnesium oxide 2Mg + O₂ 2MgO

8. Reaction of metal with water Metal + Water Metal oxide + Hydrogen Metal oxide + Water Metal Hydroxide For Example:- Sodium and Potassium react violently with cold water. The reaction is so violent and exothermic that the evolved hydrogen immediately catches fire. 2K + 2H₂O 2KOH + H₂ + Heat energy 2Na + 2H₂O 2NaOH + H₂ + Heat energy

9. Calcium also reacts with water at room temprature forming calcium hydroxide . Ca + 2H₂O Ca (OH)₂ + H₂ Reaction of metal with Acid When metal reacts with a dilute acid , then a metal salt and hydrogen gas are formed. Metal + Dilute acid Metal salt + Hydrogen E xample will shown in table on next slide

10. Metal Acid Nature of Reaction Reaction Sodium Dil. HCl Dil. H₂SO₄ Sodium reacts vigorously with dil. HCl and dil. H₂SO₄ 2Na + 2HCl 2NaCl + H₂ 2Na + 2H₂SO₄ Na₂SO ₄ + H₂ Magnesium Dil. HCl Dil. H₂SO₄ Magnesium reacts rapidly with dil. HCl and dil. H₂SO₄ Mg + 2HCl MgCl ₂ + H₂ Mg + H₂SO₄ MgSO ₄ + H₂ Zinc Dil. HCl Dil. H₂SO₄ Zinc reacts with dil.HCl and dil. H₂SO₄ at moderate rate . Zn + 2HCl ZnCl ₂ + H₂ Zn + H₂SO₄ ZnSO ₄ + H₂ Iron Dil. HCl Dil. H₂SO₄ Iron reacts with dil.HCl as well as Dil. H₂SO₄ slowly at room temprature . Fe + 2HCl FeCl ₂ + H₂ Fe + H₂SO₄ FeSO ₄ + H₂ Copper Dil. HCl Dil. H₂SO₄ Copper does not react with dil. HCl and dil. H₂SO₄ slowly at room temprature But slowly dissolve in dil. H₂SO₄ in the presence of air. No reaction 2Cu + 2H₂SO₄ + O₂ 2CuSO₄ + H₂O

11. Reaction of metal with salt solution A less reactive metal is displaced from its salt solution by a more reactive metal. Reaction of zinc with copper sulphate solution When a strip of zinc metal is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually due to the formation of colourless zinc sulphate, and red-brown copper metal is deposited on the zinc strip: CuSO ₄ + Zn ZnSO ₄ + Cu

12. Reaction of metals with Chlorine Metals react with chlorine to from ionic chlorides. For example:- Sodium is a metal. So, sodium reacts with chlorine to from an ionic chloride called sodium chloride: 2Na + Cl ₂ 2NaCl Calcium is a metal which reacts vigorously with chloride called calcium chloride: Ca + Cl ₂ CaCl ₂

13. Reaction of metal with hydrogen Only few reactive metal like sodium, potassium, calcium, and magnesium reacts with hydrogen to from metal hydrides. For example: When hydrogen gas is passed over heated sodium then sodium hydride is formed : 2Na + H₂ 2NaH When hydrogen gas is passed over heated calcium then calcium hydride is formed: Ca + H₂ Ca H ₂

14. Chemical properties of non metal Reaction of non-metals with oxygen Non-metals react with oxygen to form acidic oxides or neutral oxides . The acidic oxides of non-metals dissolves in water to form acids . C (s) + o ₂ - co ₂ Carbon oxygon carbon dioxide CO 2 (g) + H 2 O (l) – H 2 CO 3 ( aq ) carbon dioxide water carbonic acid

15. Reaction of non-metals with water Non-metals do not react with water to evolve hydrogen gas . This is because non-metals cannot give electrons to reduce the hydrogen ions of water into hydrogen gas

16. Reaction of non-metals with dilute acids Non-metals do not react with dilute acids . Non-metals do not displaces hydrogen from acids . Non-metals like carbon , sulphur or phosphorus are put into a test tube containing dilute sulphuric acid or dilute hydrochloric acid , then no hydrogen gas is evolved .

17. Reaction of non-metals with salt solutions A more reactive non-metal displaces a less reactive non-metal from its salt solution. 2NaBr ( aq ) + Cl 2 (g) - Br 2 ( aq ) + 2NaCl ( aq ) Sodium chlorine bromine Sodium Bromide chloride

18. Reaction of non-metals with chlorine Non-metals react with chlorine to form covalent chlorides which are non-electrolytes (do not conduct electricity ) H 2 (g) + Cl 2 (g) - 2HCl (g) Hydrogen chlorine hydrogen chloride (non-metal) (covalent hydride) P 4 (s) + 6Cl 2 (g) - 4PCl 3 (l) (non-metal) (covalent hydride)

19. Reaction of non-metals with hydrogen Non-metals react with hydrogen to form covalont hydrides H 2 (g) + S (l) - H 2 S (g) Hydrogen sulphur hydrogen sulphide (non-metal) (covalent hydride) N 2 (g) + 3H 2 (g) - 2NH 3 (g) Nitrogen hydrogen ammonia (non-metal) (covalent hydride)

20. Ionic compounds The compounds containing ionic bonds are called ionic compounds.Theyare formed by transfer of electrons from one atom to another . Ionic compounds are made up of positively charged ions[ cataions ]+ and negatively charged ions [anions]. Ionic compounds are also known as Electrovalent compounds .

21. Some common ions

22. Structure of ionic copounds The forces between the particles are strong. There are no free-moving electrons present, unlike in metals. There are charged particles present, but in solid state they are not free to move. When an ionic compound melts, however, the particles are free to move and the compound will conduct electricity.

23. Electron Dot Structure or Lewis Dot Diagram A notation showing the valence electrons surrounding the atomic symbol.

24. Elements within same groups have same electron dot structure

25. PROPERTIES OF IONIC COMPOUNDS

26. IONIC COMPOUNDS 1 THESE COMPOUNDS ARE USUALL CRYSTALLINE SOLIDS . BECAUSE THEIR OPPOSITELY RGED IONS ATTRACT EACH OTHER.THESE IONIC COMPOUNDS ARE HARD AND BRITTLE . IONIC COMPOUNDS HAVE HIGH MELTING AND HIGH BOILING POINT. EX – SODIUM CHLORIDE HAS HIGH MELTING POINT.

27. SOME IMPORTANT POINTS ON IONIC COMPOUNDS IONIC COMPOUNDS CONDUCT ELECTRICITY WHEN DISSOLVED IN WATER. THERE ARE PLENTY OF FREE IONS IN SOLUTION WHICH ARE ABLE TO CONDUCT ELECTRICITY. EX - ACETONE,KEROSENE etc .

28. EXPERIMENT - SODIUM CHLORIDE HEATED ON A sPATULA TAKE A SMALL AMOUNT OF SODIUM CHLORIDE ON METAL SPATULA . HESTED OVER A FLAME OF BURNER SODIUM CHLORIDE MELTS ONLY ON STRONG HEATING THIS SHOWS THAT SODIUM CHLORIDE HAS A HIGH MELTING POINT

29. EXPERIMENT- SODIUM CHLORIDE CONDUCTS ELECTRICITY FILL A BEAKER HALF WITH WATER AND DISSOLVE SOME SODIUM CHLORIDE IN IT. TWO CARBON AND ELECTRODES ARE PLACED IN IT. AN ELECTRIC SWITCH IS SET UP BY INCLUDING BATTERY BULB AND SWITCH. ON PRESSING THE SWITCH BULB LIGHTS UP . THIS MEANS THAT THE SOLUTION TAKEN IN THE BEAKER IS ALLOWS TO CONDUCT ELECTRICITY. SINCE SODIUM CHLORIDE IS AN IONIC COMPOUND CONDUCT ELECTRICITY WHEN DISSOLVE IN WATER.

30. Corrosion :- The surface of some metals gets corroded when exposed to moist air for a long time. This is called corrosion. Prevention of corrosion of metals :- The corrosion of metals can be prevented by: i ) Applying oil or grease. ii) Applying paint iii) Galvanisation ( coating of metals with non corrosive metals like zinc) iv) Electroplating ( coating of metals with non corrosive metals like chromium tin by passing electricity) v) Alloying ( Eg . When iron is alloyed with chromium and nickel, it forms stainless steel which is resistant to corrosion)

31. An alloy is a homogeneous mixture of a metal with other metals or non metal. Alloy Constituents Uses Steel iron, carbon construction of tools, machines, tanks, vehicles, ships, rails, building, bridges, dams etc. Stainless steel iron, chromium utensils, cutlery, surgical instruments etc. Brass copper, zinc utensils, handicrafts musical instruments etc. Bronze copper, tin statues, medals, bells ornament Alloys :

32. Why alloys are made? Alloys are stronger than the metals from which they are made. Alloy are harder than the constituent metals. Alloy are more resistant to corrosion. Alloy have lower melting points than the constituent metals. Alloys have lower electrical conductivity than pure metals.

33. Questing The most abundant metal in the earth’s crust is: aluminium The constituent of stainless steels are: Iron,nickel,chromium For iron to rust : both air and water are necessary Amalgam is an alloy of one or more metal: mercury