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Chemistry paper 2 - Coggle Diagram

- - - - Carbon dioxide identified by bubbling through limewater
        
        Limewater will turn cloudy
  - - - Copper ions - green flame
        
        Potassium ions -
        lilac flame
        
        Lithium ions - crimson flame
        
        Sodium ions -
        yellow flame
        
        some flame colours may be masked if the sample contains a mixture of ions
        
        clean a wire loop using hydrochloric acid
        
        hold it in the blue flame until it burns without colour
        
        dip the loop into the sample
        
        place the loop in the flame and observe the change in colour
  - - - Used to detect and identify elements and compounds
        
        Sensitive, accurate and rapid
        
        Analyse metal ions in solution
        
        The sample is placed in a flame and the light given out is passed through a spectroscope
        
        A line spectrum is produced that can be analysed to that can be analysed to identify the ions and their concentrations
  - - - Add barium chloride solution
        
        If sulfate ions are present, a white precipitate will form
        
        Ba2+ + SO4
        2- → BaSO4(s)
  - - - add silver nitrate solution
        
        coloured precipitates produce: silver chloride is white, silver bromide is cream, and silver iodide is yellow
  - - - calcium, aluminium, and magnesium ions all produce white precipitates
        
        Copper II form a blue precipitate, iron II form a green precipitate, and iron III form a brown precipitate
        
        aluminium hydroxide will redissolve in excess sodium hydroxide
- - - - increasing the pressue means the same number of particles are now in a smaller space so there are more collisions
    - - increasing the temperature increases the energy of particles, which makes them move faster and collide more
    - - increasing the concentration increases the number of particles in a given volume which also increases collisions
    - - increasing surface area makes the reaction faster from a greater area of collisions to occur
  - - - g/s or cm3/s
      - mol/s
      - units depend on those of the reactants
- - - - structural and molecular formula
      - functional group: -OH
    - - yeast
      - slightly acidified
      - anaerobic conditions
      - 37°C
    - - balanced equations
    - - pH of solution is neutral
  - - - weak acids - they only partly dissociate in water
    - - functional group: -COOH
      - structural and molecular formula
  - - - addition of hydrogen
        
        Hydrogenation
        
        produces alkanes
        
        Catalyst
      - the double bond can open up to leave a single bond
    - - addition of halogens
        
        reactions of bromine, chlorine and iodine
      - combustion
        
        carbon and carbon monoxide products
        
        incomplete combustion
        
        burns with a smoky flame
      - produces alcohols
        
        ethanol made by mixing ethene with steam
  - - - Ethene,
      - propene,
      - butene,
      - pentene
    - - this is why we cannot have methene
      - functional group
        
        the functional group affects how molecules react
      - unsaturated
- - - - Impurities in the sample will decrease the boiling point and cause the sample to boil over a wider range of temperatures
      - Impurities in the sample will increase the melting point and cause the sample to melt over a wider range of temperatures
      - a pure substance will melt/boil at a specific temperature
  - - - made by mixing the componentsin precise quantities
      - ensures the formulation has the correct properties
  - - - separation depends on the distribution of the substances between the 2 phases
    - - E.g. paper in paper chromatography
    - - the solvent moves up the paper, carrying the substances in the mixture
      - the compounds in a mixtureshould be separate into different spots (depends on solvent)
      - the more soluble a chemical, the more time it spends in the solvent, meaning it will move further up the paper
    - - A solvent, e.g. water or ethanol
    - - Rf values
        
        Different compounds have different Rf values in different solvents
        
        Allows the constituent substances of the mixture to be identified
- - - - oxygen will cause the splint to relight
  - - - chlorine will bleach the litmus paper, making it turn white
  - - - hydrogen will burn rapidly and make a squeaky pop sound
  - - - carbon dioxide makes the limewater turn cloudy
- - - - equilibrium will shift to the direction with fewer molecules
    - - increasing the pressure will move equilibrium in the direction where there are fewer gas molecules
    - - decreasing the temperature will shift equilibrium in the exothermic direction
  - - - this sign shows reversible reactions
- - - - orange bromine water decolourised if an alkene is present
    - - catalytic cracking
        
        vapours passed over hot powdered aluminium oxide catalyst
      - produces short chain alkenes and alkanes
      - steam cracking
        
        hydrocarbon vapours mixed with steam and then heated to very high temperatures
      - breaking down long chain hydrocarbons into shorter chains
        
        smaller molecules are more useful
        
        high demand
  - - - structural and molecular formulas
    - - fractional distillation
        
        produces fuels and feedstock for the petrochemical industry
        
        examples are petrol, diesel, kerosene, heavy fuel oil, and liquified petroleum
        
        petrochemical industry produces polymers, lubricants, detergents, and solvents
        
        process
        
        crude oil is vapourised
        
        vapours condense at different fractions depending on their boiling points
        
        vapours enter distillation column
        
        separates the hydrocarbonsfrom crude oil into fractions
        
        a faction contains molecules with a similar number of carbon atoms
      - hydrocarbons
        
        molecules of hydrogen and carbon only
        
        properties depends on size of the molecules
        
        flammability
        
        decreases with chain length
        
        boiling point
        
        increases with chain length
        
        viscosity
        
        increases with chain length
      - finite