What colour flame does sodium produce?
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what is qualitative analysis?
the type of substance
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the amount of substance
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Describe the test for metal cations
1. dissolve sample in water. 2. add some sodium hydroxide. 3. metal cations form insoluble precipitates
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The colours of different cation precipitates
calcium- white. aluminium- white then colourless. copper- pale blue. iron 11- green. iron 111- brown
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describe the test for halide ions
add a few drops of nitric acid then a few drops of silver nitrate. chloride- white. iodide- yellow. bromide- cream
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the test for ammonium ions
warm with sodium hydroxide. smelly alkaline gas given off. turns damp red litmus paper blue
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Why are some things added to wateR?
Chlorine- to kill microorganisms. Aluminium sulphate- to move small solids ( link with Alzheimer's) sodium fluoride- tooth decay
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Describe the test for carbonate ions
add dilute hydrochloric acid. bubbles because of co2 and turns limewater milky
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The test for sulphate ions
add water and a few drops of HCL. add a few drops of barium chloride. white precipitate if sulphate ions present
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What makes water hard?
dissolved magnesium or calcium ions
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whAT ARE the problems with hard water?
doesn't easily form a lather, ions react with soap to form precipitate called scum, this causes soap to be wasted
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What causes temporary hardness?
dissolved calcium hydrogen carbonate
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What causes permanent hardness?
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What is avogadros number?
6.02 x 10 (23) 1 mole of any substance= 1 avogadros number
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how to make a soluble salt using an insoluble reactant
1. add excess of insoluble base. 2. remove excess by filtration. 3. evaporate to produce crystals of salt or leave to cool ( slower=larger crystals)
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Getting a soluble salt using soluble reactants ( titration)
1. add acid to conical flask 2. add a few drops of phenophalein 3. fill burette with acid and note reading 3. open tap and let acid flow out slowly 4. swirl flask to mix contents 5. when indicator goes colourless close tap and note burette reading.x2
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During electrolysis where do anions and cations go?
cations to cathode and gain electrons. anions to anode and lose electrons
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what is an electrolyte?
a substance that can conduct electticiy because the ions are free to move
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uses of sodium
street lamps- gives off yellow light when electric current passes through sodium vapour. coolant in nuclear power stations- take a lot of energy to raise its temp
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Electrolysis of copper
cathode- copper ions move here, gain electrons and discharged as pure copper. anode- copper atoms lose 2 electrons, become ions, dissolve in solution and move to cathode
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cathode is object to be plated. anode is pure metal. ions from electrolyte move and are discharged on the object as metal atoms
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promote plant growth and increase yield. replace soil minerals needed for growth. cause eutrophication
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when the forwards and backwards reaction are happening at the same rate
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The Haber Process
forwards reaction exothermic. backwards endothermist. iron catalyst used, 450 degrees and 250 x ap
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Why is high pressure used in the haber process?
4 gas molecules on left, 2 on right. pressure shifts EQ to right so increases yield. too high pressure would be too expensive
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Making ethanol by fermentation
sugar + yeast makes ethanol and co2. anaerobic respiration. ethanol isn't pure
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What is the symbol for ethanol?
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Ethanol by hydration
ethene+steam and a catalyst= ethanol. ethene from cracking crude oil. produces 95% pure ethanol
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Effects of alcohol
slower reaction times, violent/aggressive behaviour, vomiting, fainting, dehydration leads to hangover
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heat fractionated column to 80 degrees. ethanol gas evaporates is condensed to produce spirits
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a series of compounds with similar physical/ chemical properties and the same general formula
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single bonds only. CnH2n+2
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double bond. CnH2n
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contain hydroxyl group ( O-H) CnH2n+1OH
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oxidised to form ethanoic acid
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reacts with base and carbonate to form euthanatise. orange- universal indicator
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C=O-O-H. CnH2n+1 COOH
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made when alcohol reacts with acid and water. pleasant, fruity smell, used in perfumes and as food flavouring
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long chain of esters, can be woven to make fleeces
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What is the symbol for ethyl ethanoate?
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Symbol for ethanoic acid?
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boil oil or fat ( esters) with concentrated alkali. esters break down to form glycerol. sodium or potassium salts are formed ( soaps)
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tail is hydrophobic- dissolves in dirt or grease. head is hydrophilic dissolves in water. soap anions get between grease and lift it off fabric
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Describe catalytic hydrogenation
oils react with hydrogen in the presence of a catalyst. the catalyst converts carbon double bonds into single bonds. unsatyrate bonds become saturate
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Other cards in this set
what is qualitative analysis?