CHEMISTRY FORM 2
- 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
- 2.1 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
- 3.1 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
- 4.1 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
- 5.1 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
- 6.1 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
Effect of an electric current on substances: Electrical conductivity of substances in aqueous state
5.0 Effect of an electric current on substances
5.3 Electrical conductivity of substances in aqueous state
Observe the effect of adding sodium chloride to water when used to complete a circuit.
NB:Forward the video to begin at the 2:45th minute.(courtesy Youtube-conductors and insulators - Electrical conductivity by The Organic Chemistry Tutor)
- What type of bond exists between sodium and chlorine in solid sodium chloride?
- What is the structure of solid sodium chloride? Explain.
- Write the formulae of sodium ions and chloride ions, indicating their state symbols when dissolved in water.
- Which ions move to the anode and which ones move to the cathode?
- Explain why sodium chloride conducts electricity in aqueous solution but not in solid state.
- Identify at least 5 other substances that conduct electricity in aqueous solutions but not in solid state (Consider solubility as well).
Answers to Questions 5.3
Ionic compounds conduct electricity in aqueous solution (if soluble) and in molten state, but not in solid state. This is because water and heat cause ions to dissociate (ionic dissociation), setting them free to move about.
During conduction, metallic ions (positive) move to the cathode and negative non-metallic ions to the anode. These properties can be used to identify substances with ionic structure.