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Q1 – What do we mean by an “oxide of a non metal”?

Before we start: Part of the focus of section two is on pollution, the sources of this pollution and the effects of pollution (acid rain for e.g.) Today’s lesson looks at acidic and basic oxides of the elements. From there we can understand better the behaviour or atmospheric pollution.

myles-evans
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Q1 – What do we mean by an “oxide of a non metal”?

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  1. Before we start: Part of the focus of section two is on pollution, the sources of this pollution and the effects of pollution (acid rain for e.g.) Today’s lesson looks at acidic and basic oxides of the elements. From there we can understand better the behaviour or atmospheric pollution.

  2. AE S2 K1 : identify oxides of non-metals which act as acids and describe the conditions under which they act as acids. Q1 – What do we mean by an “oxide of a non metal”? Examples: Carbon dioxide, sulphur dioxide, nitrogen dioxide. Q2 – How can they act as acids if they do not have hydrogen? See demo!

  3. AE S2 K1 : identify oxides of non-metals which act as acids and describe the conditions under which they act as acids. Oxides of non metals such as CO2, NO2 and SO2 dissolve in water to form acidic solutions as shown in the equations: CO2(g) + H2O (l)  __________ SO2(g) + H2O(l)  _________ NO2(g) + H2O(l) ?????????

  4. AE S2 K1 : identify oxides of non-metals which act as acids and describe the conditions under which they act as acids. Oxides of non metals such as CO2, NO2 and SO2 dissolve in water to form acidic solutions as shown in the equations: CO2(g) + H2O (l)  H2CO3(aq) SO2(g) + H2O(l)  H2SO3(aq) 2NO2(g) + H2O(l) HNO3(aq) + HNO2(aq)

  5. AE S2 K1 : identify oxides of non-metals which act as acids and describe the conditions under which they act as acids. NOTE: CO, NO, N2O are pH neutral as they do not dissolve in water.

  6. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides As discussed, oxides of non-metals dissolve in water to form acidic.

  7. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Oxides of metals dissolve in water to form basic solutions Na2O(s) + H2O(l)  ? MgO + H2O(l)  ?

  8. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Oxides of metals dissolve in water to form basic solutions Na2O(s) + H2O(l)  2NaOH(aq) MgO + H2O(l)  Mg(OH)2(aq)

  9. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides There are some elements that form oxides that show acidic and basic chemical behaviour. These are called amphoteric oxides. Where do these elements appear on the periodic table?

  10. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Elements on the border of the metals and non-metals form oxides which are amphoteric. Al2O3(s) + HCl(aq)  AlCl3(s) + H2O(l) Q1) Balance the equation Q2) How is Al2O3 acting here?

  11. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Elements on the border of the metals and non-metals form oxides which are amphoteric. Al2O3(s) + 6HCl(aq)  2AlCl3(s) + 3H2O(l) It is acting as a base.

  12. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Elements on the border of the metals and non-metals form oxides which are amphoteric. Al2O3(s) + NaOH(aq)  NaAlO2(s) + H2O(l) Q1) Balance the equation. Q2) How is Al2O3 acting here?

  13. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Elements on the border of the metals and non-metals form oxides which are amphoteric. Al2O3(s) + NaOH(aq)  NaAlO2(s) + H2O(l) It is acting as an acid.

  14. AE S2 K2 : Analyse the position of these non-metals in the PT and outline the relationship between the position of elements and the acidity/basicity of oxides Now fill in the periodic table chart! Look at p116. Shade the acidic, basic and amphoteric oxides. Write two examples of each. Write a short paragraph to answer this dot point. Key points. Acid oxides = non-metals Basic = metals Amphoteric = close to the metal/non-metal border. Q1) Which are the most acidic. Q2) Which are the most basic?

  15. What does all this mean and how can we use this information to make the world a better place?

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