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Hint
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Answer
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what's anhydrous
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without water
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what is my solution in terms of acidity if the pH is 11
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strongly alkaline
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what colour is copper carbonate powder
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green
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why is copper used in electrical wires
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good conductor of heat and electricity, ductile
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explain an experiment to obtain a pure, dry sample of a soluble salt from an insoluble reactant
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Let's look at the reaction between copper oxide and sulfuric acid. So preparing pure, dry samples of copper sulfate from copper oxide- an insoluble reactant- and sulfuric acid. This gives us copper sulfate and water. First, heat acid in a beaker to speed up the rate of reaction. Then add the base until in excess, this means that no more base dissolves so we reach a saturated solution, stir with a glass rod to ensure this. This makes sure that all our acid is neutralised. Now filter the mixture using a funnel lined with filter paper, this removes any excess base that hasn't reacted with the acid as it has reached saturation. Now gently heat the filtered solution (filtrate) to evaporate some of the water off, because remember we want anhydrous salts not hydrated. Do this until crystals begin to form on the glass rod. Then let the solution cool, this allows the hydrated crystals to form, this is since our base is less soluble in cold water, so out crystals will actually be created. Now remove the hydrated crystals via filtration and leave in a warm place so they can dry. This evaporates the rest of the water, so now we have anhydrous and pure samples of a soluble salt.
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what is a sulfate ion
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SO4 2-
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what is an alkali
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a soluble base that forms hydroxide ions when dissolved in water
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what ions do bases contain
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OH- ions ( hydroxide ions)
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what's a desiccator
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object which removes water from the surroundings using chemicals.
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what happens when sulfur is exposed to air
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reacts with oxygen in the air with a blue flame to produce sulfur dioxide, which can dissolve in water to give an acidic solution of sulfurous acid.
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what does litmus paper need to be damp
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so gas can dissolve in it and change it's colour
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what happens when magnesium is exposed to air
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it reacts with the oxygen in the air to produce magnesium oxide which is in the form of ash, this burns with a bright, white flame. Magnesium oxide ( MgO) is a base and is slightly alkaline in water so can react with an acid to produce a salt and water.
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how do you test for halide ions
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First add nitric acid ( HNO3) to remove impurities. Then add silver nitrate and if halides are present they will form a silver halide.
If chloride ions (Cl -) are present the precipitate is white (AgCl) If bromide ions (Br -) are present the precipitate is cream (AgBr) If iodide ions ( I -) are present the precipitate is yellow ( AgI) |
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describe how to extract aluminium from it's ore using electrolysis
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first aluminium ore powder (Al2O3) is mixed with cryolite ( an aluminium salt). the reason we do this is because this mixture of cryolite and Al2O3 has a lower melting point than pure Al2O3, so it costs less as less energy is needed to melt it. Once it's molten, a large voltage is applied. This causes aluminium to form at the cathode and oxygen to form at the anode. The anodes are usually made of carbon as they're cheap and a good conductor, so the oxygen produced usually reacts with the carbon anode to produce carbon dioxide, so the carbon anodes are regularly replaced. Loads of energy is needed to melt the ionic compound so it's ions can flow and conduct electricity so this process is very expensive.
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name an example of a carbonate
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copper carbonate, potassium carbonate, sodium carbonate
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what does the pH scale range from
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0-14
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what is high-carbon steel used in
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masonry nails, cutting tools
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what is air
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a mixture of gases
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what state is fluorine at room temperature
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yellow gas
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properties of low-carbon steel
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easily rusts, strong, malleable
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why is iron used in buildings
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it's very strong
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what salt will hydrochloric acid form
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chloride
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what does ductile mean
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a metal that can be drawn into a thin wire
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why is a H+ ion considered a proton
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a proton has a 1+ charge. a hydrogen atom has 1 proton and 1 electron. if it loses this electron to become H+, it will obviously just be a single proton.
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how do you test for 3 metal hydroxides
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To test for copper 2, iron 2 and iron 3 ions, first add NaOH ( sodium hydroxide ) solution to sample and observe the colour.
If copper (ii) ions (Cu 2+) are present the precipitate is blue If iron (ii) ions ( Fe 2+ ) are present the precipitate is green If iron (iii) ions (Fe 3+ ) are present the precipitate is brownish red |
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what are alkalis called
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proton acceptors as they accept H+ ions
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what is a titration
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it's a method used to find out how much of an acid (or alkali) neutralises a known volume of an alkali (or acid). It's a neutralisation reaction
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describe potassium's reaction with water
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fizzing potassium floats and moves around on water's surface very aggressively potassium catches fire with a lilac flame potassium disappears |
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what is a nitrate ion
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NO3 -
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how much indicator should you add
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a few drops
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what is brass an alloy of
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zinc and copper
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what can global warming lead to
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climate change, which is the long-term alteration of weather patterns and temperatures which pushes animals out of their habitats, causing suffering.
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when bases react with acids what form is the salt
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a colourless, aqueous solution
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if the salt is insoluble, what method do you use to extract it
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precipitation method
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describe sodium's reaction with water
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fizzing sodium floats and moves around on water's surface aggressively sodium melts into a silver ball sodium disappears |
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describe the experiment to find the percentage of oxygen in the air using phosphorus
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2 ways: 1st way do same experiment like with copper but just replace copper with phosphorus
2nd way First light phosphorus with a hot wire, phosphorus is very reactive with oxygen but not water. Phosphorus is put on an evaporating dish and floats in the water, a bell jar is placed on top of it and then a bung is put on it. The water level will rise as phosphorus pentoxide is produced and the water rises up to fill the volume of oxygen lost. Record the initial water level and leave it until it is constant. Record the end water level, you will notice that if you subtract the final volume by the initial volume and divide by the initial volume then multiply by 100, we get about 20%. So the phosphorus reacts with the oxygen to produce a phosphorus oxide called phosphorus pentoxide ( C4H10 ). This reaction emits lots of light. |
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an indicator remained colourless in neutral solution, what indicator is this
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phenolphthalein
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what is a halogen displacement reaction
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where a more reactive halogen pushes out a less reactive halogen from it's halide
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what is stainless steel mainly comprised of
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carbon, nickel and chromium
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what salt will nitric acid form
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nitrate
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what is produced when a carbonate reacts with an acid
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carbon dioxide, water and a salt
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how do you test for ammonia
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use damp, red litmus paper, this turns blue in the presence of ammonia gas, it also has a strong smell
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name the 3 most common greenhouse gases
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CH4 ----------------> methane CO2 ---------> carbon dioxide H20 ---------> water vapour |
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why is aluminium used in pots and pans
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strong when alloyed, good conductor of heat and electricity, low density
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what is produced when metals react with water
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a metal hydroxide and hydrogen gas
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what is an oxidising agent
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a substance that oxidises another substance, so it itself is reduced
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what colour flame does copper burn with
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greenish-blue
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why does reactivity decrease down group 7
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as you go down group 7, period number increases. This means the distance between the nucleus and any passing electrons is weaker. Because halogens need to gain an electron to be stable, they need as little shells as possible so the distance between them is little so the nucleus can attract a passing electron. But as forces weaken over distance, a high shell atom that's in group 7 will have a very low reactivity as it's got a large distance to try and attract an electron
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what are things reacting with when they react with air
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oxygen
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why is stainless steel resistant to corrosion
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it forms a strong, protective oxide layer
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what are the common observations to notice when group 1 metals react with water
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fizzing- hydrogen gas is released metal floats and moves about on water's surface metal vanishes metal hydroxide is produced |
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are metal oxides soluble in water
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yes, some are
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what is the colour of copper(ii) sulfate solution
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blue
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another name for low-carbon steel
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mild steel
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describe a titration between hydrochloric acid and sodium hydroxide
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first, get phenolphthalein indicator. Now, measure 25cm3 of HCl using a pipette and pipette filler, and transfer it into a conical flask. Then fill the burette with sodium hydroxide solution. After this, take an initial reading on burette and record it to 2 decimal places. Once that's done, add a few drops of phenolphthalein indicator to the flask containing HCl, this ensures we will know the end point of the neutralisation. Then add the NaOH from the burette slowly, adding it by drops towards the end until the indicator changes colour, this lets us know reaction is complete. You need to give the flask a swirl and mix well when you near the end so you get a specific answer that's exactly correct. The indicator changes colour when all the acid is neutralised, so our indicator turns pink, so we know neutralisation is complete. Now record the final volume on the burette which is the volume of NaOH needed to neutralise 25cm3 of HCl. Then repeat experiment several times, calculating a mean to allow for a more accurate result. So as NaOH is a base and HCl is an acid, we have an : acid + base --> salt + water . so our salt is NaCl and then we have H2O. We swirl flask every time alkali was added to mix the solutions. the numbers on burette increase from top to bottom, and the readings are recorded to the nearest 0.05cm3, meaning to 2 decimal places. So the 2nd decimal is 0 if on the line or 5 if in between 2 lines. And the volume of alkali is the final reading - initial reading on burette.
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what is oxidation
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gain of oxygen or loss of electrons
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what is the chemical name for rust
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hydrated iron(iii) oxide
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how does aluminium resist corrosion
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forms a thin but strong oxide layer
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why do indicators change colour
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because they react to the change in pH
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what metals can react with water
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metals above zinc in reactivity series
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