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SS1: CHEMISTRY - 1ST TERM

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  1. Introduction to Chemistry and Laboratory Apparatus | Week 1
    5Topics
    |
    1 Quiz
  2. Nature of Matter | Week 2
    3Topics
    |
    1 Quiz
  3. Separation Techniques I | Week 3
    1Topic
    |
    1 Quiz
  4. Separation Techniques II | Week 4
    5Topics
    |
    1 Quiz
  5. Particulate Nature of Matter I | Week 5
    5Topics
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    1 Quiz
  6. Particulate Nature of Matter II | Week 6
    9Topics
    |
    1 Quiz
  7. Symbols, Formulae & Oxidation Number | Week 7
    7Topics
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    1 Quiz
  8. Laws of Chemical Combination | Week 8
    4Topics
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    1 Quiz
  9. Chemical Equation & Chemical Combination (Chemical Bonding) I | Week 9
    4Topics
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    1 Quiz
  10. Chemical Combination (Chemical Bonding) II | Week 10
    4Topics
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    1 Quiz
  11. Chemical Combination (Chemical Bonding) III & Shapes of Covalent Molecules | Week 11
    3Topics
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    1 Quiz
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Matter may be classified into elements, compounds, and mixtures.

Element:

An element is a substance which cannot, by any chemical process, be split up into two, or more, simpler substances. Examples include – oxygen, hydrogen, chlorine, sodium, magnesium, etc.

Compound:

A compound is a substance which contains two or more elements, chemically combined together. Examples include water (H2O), carbon (IV) oxide (CO2), sodium chloride (NaCl), etc.

Mixture:

A mixture contains two or more constituents which can easily be separated by physical methods. The components of mixtures may be elements or compounds or both.

Types of Mixtures:

1. Homogenous Mixture.

2. Heterogeneous Mixture.

Homogenous Mixture: Sometimes called solutions are mixtures of relatively uniform composition, where the components are in the same phase. Example sugar solution, air, seawater, brass, salt solution, etc.

Heterogeneous Mixtures are mixtures in which their components are in different phases e.g kerosene and water, mud water, etc.

Other examples of mixtures are blood, crude oil, soil, urine, palm wine, milk, coca-cola.

Differences between Mixtures and Compounds

MixturesCompounds
1May be homogenous or heterogeneousAlways homogenous
2Constituent elements are not chemically bonded together and therefore can be separated by physical means.Constituent elements are chemically bonded and cannot be separated by physical method.
3Cannot be represented by chemical formula because the constituents are not in a fixed ratio.Can be represented by chemical formula because the constituents are present in a fixed ratio.
4Properties of mixtures are a sum of their individual elements.Properties of a compound differ from those of its component elements.

Essay Questions

1. (a) What is matter?  

(b) Give three physical properties of matter.

View Answer

2. Classify each of the following as physical change or chemical change 

(i) Boiling of egg                     (ii) Melting of wax 

(iii) Rusting of iron                 (iv) Digestion of Glucose

View Answer

3. Write four examples in each case of

 (a) Physical change     (b) Chemical change

View Answer

4. (a) define the following: (i) Compound (ii) Mixture

(b)Give three differences between Compound and Mixture

View Answer

5. (a) State the difference between a homogeneous mixture and a heterogeneous mixture 

(b) Classify the following into homogenous and heterogeneous mixtures; Brine, Sweat, Muddy water, Table salt, Sand, Blood

View Answer

Theory Question 1

1. (a) What is matter?  

Matter is defined as anything that has mass and occupies space.

(b) Give three physical properties of matter.

(i) Colour (ii) texture (iii) melting point

Theory Question 2

2. Classify each of the following as physical change or chemical change 

(i) Boiling of egg                     (ii) Melting of wax 

(iii) Rusting of iron                 (iv) Digestion of Glucose

 

Physical Change

Chemical Change

Melting of wax

Rusting of iron

Boiling of egg

Digestion of glucose

Theory Question 3

3. Write four examples in each case of

 (a) Physical change     (b) Chemical change

a. Physical Change

  1. Melting of wax
  2. Magnetization of iron
  3. Liquification of gases
  4. Freezing of liquid to solid

b. Chemical Change

  1. Rusting of iron
  2. Changes in electrochemical cell
  3. Slaking of lime
  4. Fermentation of substance

Theory Question 4

4. (a) define the following: (i) Compound (ii) Mixture

(b)Give three differences between Compound and Mixture

4a. (i) A compound is a substance that contains two or more elements chemically combined together. E.g. water (H2O)

(ii) A mixture contains two or more constituents which can easily be separated by physical compounds. E.g. Blood.

4b. 

 

Compound

Mixture

(i)

Always homogenous

May be homogenous or heterogenous

(ii)

Can be represented by chemical formula because the constituents are present in a fixed ratio

Cannot be represented by chemical formula because the constituents are not in a fixed ratio

(iii)

Constituents elements are chemically bonded and cannot be separated by physical method

Constituent elements are not chemically bonded together and therefore can be separated by physical means

Theory Question 5

 5. (a) State the difference between a homogeneous mixture and a heterogeneous mixture 

Answer:

Homogenous mixtures are mixtures of relatively uniform compounds where the components are on the same phase e.g. air

While

Heterogeneous mixtures are mixtures whose components are in different phases e.g. kerosene and water.

 

(b) Classify the following into homogenous and heterogeneous mixture Brine, Sweat, Muddy water, Table salt, Sand, Blood

Answer:

5b. 

Homogenous mixture

Heterogeneous mixture

Sweat, Table salt

Muddy water, Blood, Sand

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