solutions (introduction & classifications)
DESCRIPTION
introduction to the topic of solutionsTRANSCRIPT
SolutionsSolutions
SolutionsSolutions
SolutionsSolutions
Definition
• A homogeneous mixture of two or more substances
• Uniform in composition and properties
Components
• Solutes– Dissolved substances– Substance present in smaller quantity
• Solvents– Dissolving medium– Substance present in greater quantity
Test your knowledge…
Identify the solute and solvent in the following solutions:
• Potassium chloride (KCl crystals) and water
• 10cm3 acetone + 20 cm3 alcohol• 75% nitrogen gas + 25% oxygen
gas
Types
• Properties• Concentration• Ability to conduct electric current
Classification according to phase
liquidliquid
solidsolid gaseousgaseous
Classification according to Concentrations
• Saturated solutions– A solution which
contains, at a specific temperature, an amount of solute that it can normally hold in the presence of a given amount of solvent.
Classification according to Concentrations
• Unsaturated solutions– A solution which
contains less amount of solute that it can normally hold
Classification according to Concentrations
• Supersaturated solutions– A solution which
contains more solute than what it can normally hold
• Laboratory terms– Dilute
• Solutions which contains small quantity of solute relative to the solvent
– Concentrated• Solutions which contains large amounts of
solute compared to the amount of solvent present
Classification according to Concentrations
Classification according to Electrical Conductivity
• Electrolytes– Solutions that conduct electricity– Substances that are ions in solution– Cations (K+, Na+, Mg2+, Ca2+) & anions
(Cl-, CO32-)
• Non-electrolytes– Solutions that do not conduct electricity
Strong electrolyte Weak
electrolyte Non-electrolyte
Sea water Tap water Chemically pure
water
Hydrochloric acid Carbonic acid Alcohol
Sulphuric acid Acetic acid Kerosene
Aqueous copper sulphate
Ammonium hydroxide
Aqueous sugar solution
Molten lead bromide Citric acid Carbon disulphide
Aqueous sodium chloride
Oxalic acid
Nitric acid
Aqueous potassium hydroxide
Examples of Electrolytes
A simple set-up of a
conductivity apparatus