Chapter 5: Water and Solution Flashcards
State water’s characteristics.
Pure water is colourless, odourless and tasteless.
What is the density of water?
1 g cm^3
What is surface tension?
Surface tension is a result of cohesive force between the molecules of water at the surface that allows insects to stay afloat on water
What is capillary action?
Cohesive force and adhesive force between water molecules and the cell walls of xylem allow water to be drawn up from the roots to the leaves of plants
What is produced at the anode part of electrolysis?
Oxygen
What is produced at the cathode part of electrolysis?
Hydrogen
What is a solute?
A solute is a substance that can dissolve in a
liquid,
What is a solvent?
A solvent is a liquid that dissolves a substance.
What are a dilute solution, concentrated solution and saturated solution?
Dilute solution:
• Less amount of solute in the solvent
• Can dissolve more solute
Concentrated solution:
• More amount of solute in the solvent
• Can dissolve less solute
Saturated solution: • Excess amount of solute in the solvent • Cannot dissolve anymore solute and form precipitate
What is a suspension?
Suspension is a cloudy mixture formed from undissolved solute particles in a solvent.
What is solubility?
Solubility of a solute is the maximum amount of the solute that can dissolve in 100 ml of solvent at a specific temperature.
What are the factors that affect the rate of solubility?
Temperature
Rate of stirring
Size of solute
What is a colloid?
A colloid is a mixture of two or more solutes dispersed evenly in a solvent.
State 5 organic solvents and their uses.
Alcohol: Perfume, Antiseptic Kerosene: Lamp oil Turpentine: Nail varnish, Lacquer Acetone: Paint remover, Paint thinner Ether: Oil extractor
State 4 water purification methods.
- Boiling
- Filtration
- Distillation
- Chlorination
Why is water purification necessary?
Water purification is essential to remove odour, colour, taste, microorganisms and harmful chemicals so it is safe for consumption.
What does filtration do?
Removes large suspended particles such as tree branches and leaves
What does coagulation do?
- Alum is added so that mud particles stick together and sink to the bottom of the tank
- Slaked lime (calcium hydroxide) is added to reduce the acidity of water
What does oxidation do?
Increases oxygen content in the water to get rid of unpleasant smell and taste
What does sedimentation do?
Suspended particles deposit at the bottom of the tank
What do chlorination and fluoridation do?
- Chlorine is added to kill microorganisms in water
* Sodium fluoride is added to prevent tooth decay
State laws to ensure industrial waste is treated
before being discharged into the river.
- Environmental Quality (Scheduled Wastes) Regulations 2005
- Environmental Quality (Industrial Effluent) Regulations 2009
- Environmental Quality (Sewage) Regulations 2009
