Chemistry Topic 2

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Group 0 elements.
Noble gases. Inert- don't react much with anything, full outer shell so don't need to.
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Group 1 elements.
Alkali metals. Water=vigorous reaction makes metal hydroxide solution+H2. Go down=more reactive. Go up= electrons more easily lost.
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Group 7 elements.
Halogen. Atomic number increases= elements darker colour + higher boiling point. Higher up = more reactive, shell with missing electron nearer to nucleus, pull from +ve ions is greater.
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Chlorine properties.
Atomic number: 17. Colour: green. Physical state at room temp: gas. Boiling point: -34 degrees C.
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Bromine properties.
Atomic number: 35. Colour: red-brown. Physical state at room temp: liquid. Boiling point: 59 degrees C.
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Iodine properties.
Atomic number: 53. Colour: dark grey. Physical state at room temp: solid. Boiling point: 185 degrees C.
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Why does hydrogen chloride gas dissociate in water?
Halogens combine with hydrogen to form hydrogen halides. HCl is a gas at room temp. When HCl is dissolved in H2O, the HCl molecules split up into H+ ions and Cl- ions.
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Why does hydrogen chloride gas not dissociate in methylbenzene?
If HCl is dissolved in an organic solvent, it doesn't dissociate into H+ ions and Cl- ions. (No H+ ions = not acidic)
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What is a displacement reaction?
A more reactive element pushes out a less reactive element from a compound.
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Displacement of chlorine water (colourless) with potassium chloride solution (colourless).
No reaction.
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Displacement of chlorine water (colourless) with potassium bromide solution (colourless).
Orange solution (Br2) formed.
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Displacement of chlorine water (colourless) with potassium iodide solution (colourless).
Brown solution (I2) formed.
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Displacement of bromine water (orange) with potassium chloride solution (colourless).
No reaction.
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Displacement of bromine water (orange) with potassium bromide solution (colourless).
No reaction.
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Displacement of bromine water (orange) with potassium iodide solution (colourless).
Brown solution (I2) formed.
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Displacement of iodine water (brown) with potassium chloride solution (colourless).
No reaction.
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Displacement of iodine water (brown) with potassium bromide solution (colourless).
No reaction.
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Displacement of iodine water (brown) with potassium iodide solution (colourless).
No reaction.
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What do halogen displacement reactions involve?
A transfer of electrons. EG: Cl2 (aq) + 2KI (aq) -< I2 (aq) + 2KCl (aq). Electrons are passed from the iodine to the chlorine.
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OIL RIG.
Oxidation Is Loss, Reduction Is Gain *OF ELECTRONS*
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What are redox reactions?
Reactions where reduction and oxidation happen at the same time. An oxidising agent accepts electrons and gets reduced, a reducing agent donates electrons and gets oxidised.
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Acid + Metal -> Salt + Hydrogen.
.
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How do you work out how reactive a metal is? (using the formula acid+metal-> salt + hydrogen)
The more reactive the metal, the faster the reaction will go. The speed of reaction is indicated by the rate at which the bubbles of hydrogen are given off.
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The name of the salt depends on the metal and acid used.
Hydrochloric acid will always produce chloride salts, and sulfuric acid will always produce sulfate salts, in the equation acid+metal-> salt+hydrogen
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Equation for metals reacting with water.
Metal + water -> metal hydroxide + hydrogen
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The reactivity series.
K, Na, Li, Ca, Mg, Al, Zn, Fe, Cu, Ag, Au.
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Why will a more reactive metal displace a less reactive metal from its oxide?
More reactive metal displaces a less reactive metal from its oxide because it will bond more strongly to the oxygen. If you put a reactive metal into a solution of a less reactive metal salt the reactive metal will replace the less reactive metal in
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Word equation for the rusting of iron.
iron + oxygen + water -> hydrated iron (III) oxide (RUST)
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Why does iron make rust?
Iron corrodes easily. Rusting only happens when the iron's in contact with both oxygen from the air and water. this is an oxidation reaction.
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How do you prevent the rusting of iron?
Barrier Methods: painting/coating with plastic, oiling/greasing. Sacrificial method: place a more reactive metal with the iron, the water and oxygen will react with that instead (EG ZINC).
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Gases in the atmosphere.
78% nitrogen, 21% oxygen, nearly 1% argon, 0.04% CO2.
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How do you investigate the proportion of oxygen in the atmosphere using copper?
When heated, copper reacts with oxygen in the air to make copper (II) oxide (reaction uses up oxygen). Heat excess of copper in a tube, pass air over it using two syringes, can use markers on syringes to tell how much oxygen has been used up.
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What is the chemical equation for the reaction of copper and air?
2CU + O2 -> 2CuO
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How do you investigate the proportion of oxygen in the atmosphere using iron?
Iron w/ oxygen =rust- iron will remove O2 from air. Soak some iron wool in acetic acid, push wool into test tube, thumb over end, invert tube into beaker of water, level of water rises (filling up space oxygen took). Measure difference start&end.
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How do you investigate the proportion of oxygen in the atmosphere using phosphorus?
White phosphorus smoulders in air to produce phosphorus oxide. Calculate the amount of oxygen in the air in the same way as for iron.
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How do you make pure oxygen?
Made from hydrogen peroxide. H2O2 decomposes into H2O and O2. Slow reaction, sped up with manganese(IV) oxide catalyst. Collect oxygen over water or using gas syringe.
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What is the equation to make pure oxygen?
2H2O2 (aq) -> 2H2O (l) + O2 (g)
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Burning of magnesium in air.
Magnesium burns with a bright white flame in air and white powder formed is magnesium oxide. Slightly alkaline when dissolved in water. 2Mg(s) + O2(g) -> 2MgO
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Burning of carbon in air.
Burns if heated very strongly. Orangey/yellow flame, produces CO2 gas. Slightly acidic when dissolved in water. C(s) + O2(g) -> CO2(g)
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Burning of sulfur in air.
Pale blue flame, produces sulfur dioxide. Acidic when dissolved in water. S(s) + O2(g) -> SO2(g)
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How do you collect gasses in a test tube?
Delivery tube fed directly into test tube. Upward delivery to collect 'lighter than air' gases (eg H2). Downward delivery for 'heavier than air' gases (eg CO2, Cl2)
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The reaction of dilute acid with calcium carbonate to produce carbon dioxide.
The calcium carbonate (marble chips) placed in bottom of a flask and dilute HCl added. HCl reactes with calcium carbonate, produce calcium chloride, water, CO2 gas. CO2 collected in gas syringe, or using downward delivery.
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What is the equation for the reaction for calcium carbonate with dilute acid?
2HCl (aq) + CaCO3 (s) -> CaCl2 (aq) + H2O (l) + CO2 (g)
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How does the thermal decomposition of metal carbonates produce CO2?
Heat a metal carbonate, substance breaks down into simpler substances when heated.
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The thermal decomposition of copper(II) carbonate.
Copper (II) carbonate is a green power, easily decomposes to form CO2 and copper (II) oxide when heated. Heat copper(II) carbonate and collect gas using downward delivery method. CuCO3 (s) -> CuO (s) + CO2 (g)
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What is CO2?
Slightly soluble in water, produce slightly acidic solution when dissolved in water. CO2(g)+H2O(l)->H2CO3(aq)
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Uses of CO2.
Fire extinguishers, carbonated drinks. CO2 is more dense than air so sinks onto flames and stops the O2 reaching the fire, used when water fire extinguishers aren't safe (EG electrical fires).
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Carbon dioxide is a greenhouse gas.
Absorb most of the heat that would normally be radiated out into space, re-radiate it in all directions. Deforestation, burning fossil fuels.
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How is increasing carbon dioxide linked to climate change?
Correlation between increasing levels of CO2 and the gradual heating up of Earth's atmosphere.
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Flame tests (to identify metal ions) results.
Lithium:crimson-red flame. Sodium:yellow-orange flame. Potassium:lilac flame. Calcium:brick-red flame.
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How do you carry out a flame test?
Clean platinum wire loop by dipping it in dilute HCl, hold in a flame. Once loop burns without any colour, dip it into sample then place back into the flame.
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What metals from a coloured precipitate with NaOH?
Copper(II): blue precipitate, Cu^2+(aq) + 2OH-(aq)->Cu(OH)2(s). Iron(II):sludgy green, Fe^2+(aq)+2OH-(aq)->Fe(OH)2(s). Iron(III):reddish brown, Fe^3+(aq)+3OH-(aq)->Fe(OH)3(s).
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How do you test for metal ions?
Many metal hydroxides are insoluble and precipitate out of solution when formed. Add a few drops of sodium hydroxide to solution of compound in test tube. Coloured insoluble hydroxide will form.
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How do you check for ammonia gas?
Use a damp piece of red litmus paper, if ammonium present the paper will turn blue. Add some sodium hydroxide to soluytion of substance in test tube, if ammonia given off this means there are ammonium ions in substance.
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How can HCl help to detect carbonates?
Carbonates give off Co2, with HCl. Add dilute HCl to test sample, CO2 released if carbonates present. CO3^2-(s) + 2H+(aq) -> CO2(g) +H2O(l)
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How do you test for sulfates with HCl and barium chloride? *ppt means precipitate*
Sulfate ions make white ppt. Add dilute HCl followed by barium chloride solutioon. White precipitate of barium sulfate=original compound was a sulfate. HCl is added to get rid of traces of carbonate+sulfate ions before. Ba^2+(aq)+SO4^2-(aq)->BaSO4(s)
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Test for halides with nitric acid and silver nitrate.
Add dilute nitric acid followed by silver nitrate solution. Chloride ion=white ppt of silver chloride. Bromide ion=cream ppt of silver bromide. Iodide ion=yellow ppt of silver iodidde.
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Test for chlorine.
Chlorine bleaches damp litmus paper white.
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Test for oxygen.
Oxygen relights a glowing splint.
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Test for carbon dioxide.
Carbon dioxide turns limewater cloudy- bubble gas through a test tube of limewater.
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Test for hydrogen.
Hydrogen makes a squeaky pop with a lighted splint.
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Test for ammonia.
Ammonia turns damp red litmus paper blue.
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How do you test for water?
When copper(II) sulfate bound to water, blue crystals form. Heat the blue hydrated copper(II) sulfate crystals, drives watter off. Leaves white anhydrous copper(II) sulfate power. Add drops of H2O and it will turn blue again. Pure water boils at 100.
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Other cards in this set

Card 2

Front

Group 1 elements.

Back

Alkali metals. Water=vigorous reaction makes metal hydroxide solution+H2. Go down=more reactive. Go up= electrons more easily lost.

Card 3

Front

Group 7 elements.

Back

Preview of the front of card 3

Card 4

Front

Chlorine properties.

Back

Preview of the front of card 4

Card 5

Front

Bromine properties.

Back

Preview of the front of card 5
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