Getting substances

• the is unit for mass is kilogram (kg)
• the si unit for temperature is kelvin (k)
• si unit for time is second (s)
• 1kg = 1000g
• 1g = 1000mg
• 1 tonne = 1000kg
• kelvin = degree Celsius +273
• 1ms = 0.001s
• 1 min = 60 seconds
• 1hr = 60 min = 3600 seconds
• beam balance is accurate to +- 0.1g
• electronic balance accurate to +-0.01g
• digital thermometer accurate to +-0.1 degree Celsius
• mercury/alcohol thermometer accurate to +-0.5 degree Celsius
• Burette is accurate to 0.05cm cube
• pipette can be used to measure liquids in fixed volumes
• displacement of water is used to measure gases that are insoluble or slightly soluble in water
• downward delivery is used for gases which are denser than air AND soluble in water
• upward delivery is used when gases are less dense than air AND soluble in water
• gas syringes are use to monitor the rate of evolution of the gas produced
• drawing for setup of displacement of water

  
• Drawing for downward delivery

  
• Upward delivery

  
• drawing for seperation using a gas syringe

  
• use concentrated sulfriction acid, using quicklime and using fused calcium chloride to dry a gas
• add concentrated sulfuric acid only when gases are acidic, or do not react with acids. CANNOT use alkaline gases that react with sulfuric acid
• use quicklime for alkaline gases. CANNOT use for acidic gases that react with bases, such as calcium oxide
• quicklime must be heated before use to absorb moisture and carbon dioxide from the air. the dryer it is, the more effective it is
• use magnetic attraction to separate magnetic substance from non magnetic substance
• use sieving when particles are of different sizes, with one particle being larger than the sieves pore size, and one being smaller
• use solvent to separate when there is two solids, where one is soluble in the solvent and one is not.
• use sublimation to separate a solid that sublimes from one that does not
• sublimation is the process of changing directly from solid to gaseous state on heating
• Use filtration to spectate insoluble solids from liquids
• filtration steps:

  1. put mixture into a filter funnel that is lined with filter paper.
  2. collect filtrate in a conical flask
  3. collect residue and dry it on a piece of filter paper
• Filtrate is a liquid or solution that passes through the filter paper
• residue is a solid that remains on the filter paper
• evaporation to dryness is used to obtain solid (solute) from a solution by heating the solution until all the solvent has been boiled off
• crystalliastion is used to obtain pure solid from its solution
• crystals are formed when the solvent is removed by heating a solution until a hot saturated solution is formed. upon cooling, the solute will form pure crystals.