JOM KIMIA A1

Let study about Kinetic Theory of Matter.

1.   Matter is anything that occupies space and has mass.  Matter exists in three

      states which is solid, liquid and gas.

2.   Matter is made up of tiny and discrete particles.

3.   An atom is the smallest particle of an element that can participate in a chemical

      reaction.

4.   An ion is a positively-charged or negatively-charged particle.

5.   Particles in matter are in motion.

6.   Diffusion occurs when particles of a substance move in between the particles of 

      another subtance.

7.   Diffusion of matter occurs most rapidly in gases, slower in liquids and slowest in

      solids, due to the different arrangement and movement of particles in the three  

      states of matter.

8.   The change in heat changes the state of matter.

10. When a substance is heated, the particles gain kinetic energy and move faster.

11. When a substance is cooled, the particles loss their kinetic energy and move

      slower.

 

The kinetic theory of matter;

State of Matter Characteristic	solid	liquid	gas
Arrangement of particles	are packed closely together in an orderly manner	are packed closely together but not in orderly manner	Very far apart and in a random motion
Forces of attraction	Strong forces	Strong forces but weaker than the forces in a solid	Weak forces
Movement of particles	Particles vibrate and rotate about their fixed positon	Particles vibrate, rotate and move throughout the liquid.  They collide against each other	Particles vibrate, rotate and move freely. The rate of collision is greater than in liquid
Shape / volume	- has a fixed volume and shape	- has a fixed volume and follows the shape of the container	Does not have a fixed shape of volume
compressibility	Cannot be compressed	Cannot be compressed easily	Can be compressed easily

 

 

The Atomic Structure

A History Of An Atom

 

 

John Dalton  

Imagined the atom as a small indivisible ball similar to a very tiny ball.

 

J.J Thomson

He discovers the electron.

He described the atom as a sphere/cloud of positive charge which contains a few negatively-charged particles called electrons.

 

 

Ernest Rutherford 

He discovers the proton.

He suggested that protons are concentrated in the center of the atom called the nucleus, with a cloud of electrons surrounding the nucleus

 

 

Niels Bohr

He suggested that the electrons are moved in definite orbits surrounding the nucleus.

 

 

 

James Chadwick 

He discovered the neutron. He suggested that nucleus consists of protons and neutrons, with the nucleus surrounded by electron shells.

 

 

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What is Acid and Base?

 

 

Definition;

An acid is a chemical substance, which ionizes in water to produce hydrogen ions, H⁺ 

 

 

A base is a chemical substance that can neutralize an acid to produce a salt and water,  or

 

A base is a chemical substance, which ionizes in water to produce hydroxide ions, OH^-

 

 

Basicity of an acid is the number of mole of H⁺ ion that can be produced by one mole of acid when it dissolves in water.

Monoprotic acid	Ionisation
Hydrochloric acid, HCl	HCl  →   H+  +  Cl-
Ethanoic acid, CH3COOH	CH3COOH  →  H+  +  CH3COO-

 

Diprotic acid	Ionisation
Sulphuric acid, H2SO­4	H2SO4  →  2H+  +  SO42-

 

Chemicals Properties of Acid

a.   Acids react with bases/metal oxide to form salts and water.

      Examples;     

i.    H₂SO₄   +   ZnO   →   ZnSO₄   +   H₂O

 

                   ii.   2HCl   +   CuO   →   CuCl₂   +   H₂O

 

 

b.   Acids react with alkalis to form salts and water.

      Examples;     

i.   HCl   +   NaOH   →   NaCl   +   H₂O                   

 

ii.  H₂SO₄   +   Ca(OH)₂   →   CaSO₄   +   2H₂O

 

 

c.   Acids react with reactive metal to produce salts and hydrogen gas.

      Examples;

i.   2HCl   +   Mg   →   MgCl₂   +   H₂             

 

ii.  H₂SO₄   +   Zn   →   ZnSO₄   +   H₂

 

          Reactive metals: Mg, Al, Zn (use this metals only)

 

 

d.   Acids react with carbonate compound to produce salts, water and carbon

      dioxide.

Examples;

i.   2HCl   +   PbCO₃   →   PbCl₂   +   CO₂   +  H₂O                    

 

ii. H₂SO4   +   CuCO₃   →   CuSO₄   +   CO₂ +  H₂O

 

 

BASES

Most bases are not soluble in water. Bases that are soluble in water are known as alkalis.

 

Na₂O   +  H₂O  →   2NaOH 

Base                                alkali

 

CaO    +   H₂O  →   Ca(OH)₂

Base                                alkaliIn water, an alkali dissociates to produce hydroxide ions, OH- and cations.

Bases that are insoluble in water	Bases that are soluble in water
Zinc oxide, ZnO	Sodium oxide, Na2O
Zinc hydroxide, Zn(OH)2	Sodium hydroxide, NaOH
Copper(II) oxide, CuO	Potassium oxide, K2O
Copper(II) hydroxide, Cu(OH)­2	Potassium hydroxide, KOH
	Calcium hydroxide, Ca(OH)2

 

Chemicals Properties of Alkalis

a.   Alkalis react with acids to form salts and water.

      Examples;

i.   NaOH   +    HCl      →   NaCl   +   H₂O               

 

ii.  Ca(OH)₂   +   H₂SO₄   →   CaSO₄   +   2H₂O 

 

 

b.   When a mixture of an alkali and an ammonium salt is heated, ammonia

      gas is, NH₃ is liberated.

      Examples;

i.   NaOH   +    NH₄Cl      →   NaCl   +   H₂O  +   NH₃               

 

                    ii.  Ca(OH)₂   +   2NH₄Cl   →   CaCl₂   +   2H₂O   +   2NH₃ 

 

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Many students said this chapter is difficult. How about you?

Let me help you to explore this chapter.

 

What is salt?

Salt is an ionic compound formed when the hydrogen ion, H⁺ from acid is replaced by a metal ion or ammonium ion, NH₄⁺

 

In the preparation of salts, we must identify the type of salt.  

This can be done by analyzing the cations and the anions that are present in salts.

 

 Two types of salts

• Soluble salt     : salts that can be dissolve in water at room temperature
• Insoluble salt   : salts cannot be dissolve in water at room temperature

 

 

Salt	Solubility in water
Sodium, potassium and ammonium salts (Na+, K+, NH4+)	·    All are soluble
Nitrate salt (NO3-)	·    All are soluble
Chloride salt (Cl -)	·    All chloride salts are soluble in water except PbCl2, AgCl and HgCl2
Sulphate salt (SO42-)	·    All sulphate salts are soluble in water except PbSO4, BaSO4 and CaSO4
Carbonate salt (CO32-)	·    All carbonate salts are insoluble except Na2CO3, K2CO3 and (NH4)2CO3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PbCl₂, AgCl and HgCl₂               : P A H   chloride

     

 

PbSO₄, BaSO₄ and CaSO_{4          :}P B C   sulphate

 

The table shows the colour of salts in solid , in aqueous solution

 and the solubility of salts in water

Name of Salt	Colour in solid	Solubility in water	Colour in Aqueous solution
1. Ammonium chloride      NH4Cl	white	soluble	colourless
2. Ammonium nitrate     NH4(NO3)3	white	soluble	colourless
3. Calcium carbonate     CaCO3	white	insoluble	-
4. Calcium nitrate     Ca(NO3)2	white	soluble	colourless
5. Magnesium sulphate     MgSO4	white	soluble	colourless
6. Magnesium carbonate     MgCO3	white	insoluble	-
7. Zinc sulphate     Zn SO4	white	soluble	colourless
8. Zinc nitrate      Zn(NO3)2	white	soluble	colourless
9. Lead(II) chloride,     PbCl2	white	insoluble	-
10. Lead(II) sulphate,        PbSO4	white	insoluble	-
11. Lead(II) carbonate,       PbCO3	white	insoluble	-
12. Copper(II) chloride,       CuCl2	Blue	soluble	Blue
13  Copper(II) sulphate,       PbSO4	Blue	soluble	Blue
14. Copper(II) carbonate        PbCO3	Green	insoluble	-
15. Iron(II) sulphate ,       FeSO4	Green	soluble	Pale green
16. Iron(III) chloride ,        FeCl3	Brown	soluble	Yellowish brown
17. Sodium nitrate ,       NaNO3	white	soluble	colourless

 

 

 

The table shows the colour of different cations in the solid form

or in aqueous solution

Observation	Inference
Blue solution	Ion copper (Cu2+ ) present
Pale green  solution	Ion Iron(II) Fe2+ present
Yellow/Yellowish-brown/brown solution	Ion Iron (III) Fe3+ present
Green solid	Hydrated Fe 2+, CuCO3
Brown solid	Hydrated Fe 3+ salt
White solid	Salts of Na+ , K+ ,NH4+, Mg 2+, Ca 2+ Al 3+ , Zn 2+, Pb 2+ (If the anions are colourless
Colourless solution	Na+ , K+ ,NH4+, Mg 2+, Ca 2+ ,  Al 3+ , Zn 2+, Pb 2+

 

 

 

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