To measure a range of volumes to the nearest 0.5 cm3
What is the function of a burette
To measure volumes to the nearest 0.05cm3
How to measure gases
Using the gas syringe
What are the methods to collect gases
Displacement of water, upward delivery, and downward delivery
What gases are suitable for displacement of water
Gases that are insoluble or slightly soluble in water. Since these gases do not dissolve in water, they would rise to the top of the gas jar and be collected there.
What gases are suitable for upward delivery
Gases that are less dense than air.
What gases are suitable for downward delivery
Gases that are more dense than air
How to know whether a gas is denser than air
If their molecular mass is higher than air, which is 39
What are the three drying agents
Concentrated sulfuric acid, quicklime (calcium oxide), and fused calcium chloride
Which gases are not suitable for concentrated sulfuric acid
Gases that react with sulfuric acid
Which gases are not suitable for quicklime
Gases that react with calcium oxide
What gases are not suitable for fused calcium chloride
Gases that react with calcium chloride
What should be done before using quicklime
Freshly heat quicklime, as calcium oxide absorbsmoisture and carbon dioxide from the air
What should be done before using fused calcium chloride
Freshly heat the calcium chloride, as calcium chloride readily reacts with the moisture and carbon dioxide from the air
What are the separation techniques to separate solid-solid mixtures
Filtration, Evaporation to dryness, Crystallization, and simple distillation
What are the steps to perform filtration
Pour the solution into a beaker, through a filter funnel with filter paper
Collect the filtrate from the beaker
Collect the residue from the filter paper
What are the steps to perform crystallization
Heat the solution until a saturated solution is formed
Cool the saturated solution until crystals are formed
Filter the crystals and collect them from the filter paper
Wash the crystals with distilled cold water and dry the crystals with the filter paper
How are crystals formed
When the liquid is heated from the solution, the volume of the solvent decreases, causing the amount of solute to dissolve in the solvent to also decrease. Hence, the solute that cannot be dissolved would form crystals
How do we perform simple distillation
Heat the solution
When the thermometer shows 100 degree celcius, the solution will start to boil
Vapour will pass through the condenser
The condenser cools the vapour, causing the vapour to condense into liquid, that will be collected as the distillate
What is the function of the condenser in a simple distillation set up
To cool and condense the vapour so that the vapour can condense into a liquid that will be collected as the distillate
What is the function of boiling chips in a simple distillation set up
To ensure smooth boiling
What is the function of a thermometer in a simple distillation set up
To measure the temperature of the vapour before it passes into the condenser
What are the separation techniques to separate solid-solid mixtures
Magnetic attraction, sublimation, and sieving
What are examples of magnetic materials
Steel, Iron, Nickel, and Colbalt
What is the meaning of sublime
The ability of a substance to change from a solid to gas directly
What is the difference between fractional distillation and simple distillation
Fractional distillation separates liquids with differentboiling points, while simple distillation separates liquids with similar boiling points
What happens during fractional distillation
Liquids in the round bottom flask would gain heat and start to boil. The liquids with the higher boiling point with condense along the fractionating column and return to the round bottom flask, while the liquid with the lowest boiling point would reach the top of the round bottom flask and pass through the condenser, losing heat and condensing to form a liquid that will be collected as the distillate