Chemistry Paper 3

    Cards (43)

    • Liquid
      A state of matter where particles are close together but can move freely.
    • Gas
      A state of matter where particles are far apart and can move freely.
    • Melting
      Solid to a Liquid
    • Freezing
      Liquid to solid
    • Condensing
      Gas to a Liquid
    • Evaporating/Boiling
      Liquid to a Gas
    • Sublimiation
      Solid to a Gas
    • Desublimation
      Gas to a Solid
    • What is an element
      A substance that consists of only atoms with the same atomic number
    • What is a compound?

      A compound is a substance composed of two or more elements chemically bonded together.
    • What is a pure substance?

      Consists of only one element or compund
    • What do you use Simple Distillation for?

      Separate a solvent from a solution
    • What apparatus do you need for simple distillation?

      Heat source, Condenser,Round bottom flask, reciever flask
    • How does simple distillation work?

      Separating liquids based on their boiling points.
      • The solvent boils because it has a lower boiling point
      • The solvent vapour passes into the condenser
      • The vapour is cooled and condensed back to liquid state
      • The liquid reaches the receiver flask
    • What do you use Fractional Distillation for?

      To separate a liquid from a mixture of liquids
    • What apparatus do you need for fractional distillation?

      Round bottom flask, Fractioning Column, Condenser, Flask
    • How does Fraction Distillation work?

      The liquids in the mixture have different boiling points
      When the mixture is heated
      • The mixture boils
      • Hot vapour rises up the fractioning column
      • Vapour condenses when it hits the cool surface of the column and drips back
      • The fraction with the lowest boiling point reaches the top first
      • It vapour passes into condenser
    • What do you use filtration for?

      Separate an insoluble substance from a liquid or a solution.
    • Why do we use filtration?

      • To purify a liquid or a solution by removing solid impurities from it
      • To separate the solid you want from the liquid it is mixed with
    • What apparatus do you need for filtration?

      Two beakers -> One with mixture, Other empty
      Filter funnel
      Filter paper
    • How does filtration work?

      The mixture is poured through the filter paper and funnel. The solid is left in the paper and liquid residue is left in the beaker underneath
    • How does filter paper benefit a filtration practical?

      • Paper has tiny pores -> Water molecules and dissolved substances can run through.
      • Small enough to stop insoluble solid particles going through
    • What do you use crystallisation for?

      To produce solid crystals from a solution
    • What apparatus do you need for crystallisation?

      Heat source, Evaporating Basin, Tripod.
    • How does crystallisation work?

      • The solution is heated to remove enough solvent to produce a saturated solution
      • The saturated solution cools when solids start to form in the solution
      • Once cool and the water has evaporated, solid crystals are formed
    • What is paper chromatography used for?

      Separate mixtures of soluble substances
    • What is the stationary phase?

      The stationary phase is the phase in chromatography where the sample components do not move
    • What is the mobile phase?

      The solvent that moves through the stationary phase
    • How does paper chromatography work?

      • A pencil line is drawn onto the chromatography paper.
      • The Ink is dotted onto the pencil line
      • The paper is then lowered into the solvent and the ink spreads up the paper
      • You then measure the distance from the solvent front and the distance the ink moved to calculate the Rf value
    • How do you calculate the Rf value?

      Distance traveled by spot/ Distance traveled by solvent
    • What does potable water mean?

      Water that is safe to drink
    • What must potable water have?

      • Low levels of contaminating substances
      • Low levels of microbes
    • What are the stages of water treatment?
      1. Sedimentation - Large insoluble particles sink to the bottom of a tank
      2. Filtration - Small insoluble particles are removed by filtering through beds of sand
      3. Chlorination - Chlorine gas is bubbled from the water to kill microbes
    • What are Acids?

      Substances that have a pH less than 7
      (a source of hydrogen ions)
    • What are Alkali's
      Substances that have a pH over 7
      (source of hydroxide ions)
    • What is the pH scale?

      The pH scale is a measure of the acidity or alkalinity of a solution, ranging from 0 (most acidic) to 14 (most alkaline). Neutral =7
    • The strength and concentration determines...
      pH
    • What is a base?

      Any substance that reacts with an acid to form a salt and water.
    • Base + Acid=
      Salt+Water
    • How do you name a salt?
      First part - the metal in the base
      Second part - from the acid used