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Hint
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Answer
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what indicator turns pink in alkali
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phenolphthalein
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what does brittle mean
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cannot bend without breaking, very unflexible, not malleable, etc
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what is an ore
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a rock that contains a metal compound or a metal
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how do you test for water
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add anhydrous copper (ii) sulfate to the sample and if water is present the solution turns from white to blue.
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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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describe the greenhouse effect
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the sun emits short wavelength radiation Earth absorbs and reflects this as long wavelength radiation greenhouse gases cannot absorb short wavelength but can absorb long wavelength greenhouse gases absorb reflected radiaiton they re-radiate it as heat energy towards space, Earth and other greenhouse gases then the greenhouse gases that have recieved radiation from other greenhouse gases do the exact same thing as the other greenhouse gases have done, reflect it towards other greenhouse gases, towards Earth and space so heat stays in the atmosphere for longer than it should this heats up the Earth This is good and vital for life, but if too extreme it can cause global warming |
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what metals can react with acid
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metals above hydrogen in reactivity series
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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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why does testing for metal hydroxides work
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most metal hydroxides are insoluble and will precipitate out of the solution if formed. some of these precipitates have a unique colour. So if you get your coloured, insoluble metal hydroxide you can tell what metal was in the compound
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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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why do we not use universal indicator in titrations
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because it has a wide range of colours depending on the specific pH, so the change is too gradual meaning it is hard to see when the exact end point of the titration is. It doesn't have 1 specific colour for an acid, neutral and alkali like other indicators.
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what are things reacting with when they react with air
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oxygen
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how does the sacrificial method work
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by attaching a more reactive metal than the protected metal, this ensures if the protected metal gets into contact with oxygen and water then corrosion will not take place since oxygen and water are reacting with the more reactive metal
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name the 5 group 7 elements in order of reactivity
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astatine, iodine, bromine, chlorine, fluorine
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what are the main ways you coat a substance to stop corrosion
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electroplating, greasing, coating with plastic and painting
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what do metal carbonates thermally decompose into
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carbon dioxide and a metal oxide
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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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what ions do acids contain
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hydrogen ions
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what is produced when metals react with oxygen
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a metal oxide
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what is reduction
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loss of oxygen or gain of electrons
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what is a salt
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an ionic compound
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why is aluminium used in cans and aircraft
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it has a low density and resists corrosion
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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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explain how you would prepare a pure dry sample of lead (ii) sulfate
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First, our reactants are lead (ii) nitrate and sodium sulfate. This gives sodium nitrate and lead (ii) sulfate. So our reaction is obtaining a pure, dry sample of lead ( ii) sulfate from 2 soluble reactants, lead ( ii) nitrate and sodium sulfate. We use the precipitation method. First, mix similar volumes of lead ( ii) nitrate with sodium sulfate in a beaker. The exact volumes are totally irrelevant, any excess is removed later. A white precipitate of lead (ii) sulfate forms. This mixture is filtered, the precipitate on the filter paper is washed with distilled water to remove impurities. The precipitate is transferred to a warm place where it can dry, like a warm oven or desiccator, this removes water, producing anhydrous lead (ii) sulfate crystals.
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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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why is iron used in saucepans
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good conductor of heat, high melting point, malleable
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what trend does group 1 have as you go down the group
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reactivity increases boiling/melting point decreases density/ mass increases |
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what is a nitrate ion
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NO3 -
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are carbonates soluble
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no, except sodium carbonate, potassium carbonate and ammonium carbonate
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what is a sulfate ion
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SO4 2-
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what is the result of the greenhouse effect
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global warming
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what is the oxide that dissolves in water to produce limewater
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calcium oxide
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what is an alloy
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substance made of 2 or more different elements where at least 1 is a metal
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how do you test for carbonate ions
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First add HCl. This HCl is not for removing impurities. If carbonate ions ( CO3 2-) are present then fizzing is noticed which is carbon dioxide being made. To ensure this is definitely carbon dioxide, bubble it through limewater, if it's present it turns from colourless to cloudy.
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what is brass an alloy of
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zinc and copper
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what is a carbonate
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a compound made of a metal and carbonate ions
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name an example of a carbonate
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copper carbonate, potassium carbonate, sodium carbonate
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why is an alloy stronger than a pure metal
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because an alloy has different elements with different sized ions which ruins the regular lattice arrangement of a pure metal. pure metals have a regular lattice arrangement so their layers can slide over each other, but alloys don't have this arrangement so their layers cannot slide over one another as easily.
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what state is chlorine at room temperature
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green gas
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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 do indicators change colour
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because they react to the change in pH
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what is stainless steel mainly comprised of
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carbon, nickel and chromium
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when carbonates react with acids a fizzing is noticed, what is this.
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carbon dioxide (CO2)
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what is a halide
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metal + halogen
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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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what is a valence electron
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outer shell electron
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why is iron used in buildings
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it's very strong
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are all group 7 elements diatomic
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no, astatine and tennessine are controversial, we are unsure if they exist, but some people say they do exist.
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what is a conical flask
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a generic flask
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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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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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how do bases neutralise acids
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combining with the H+ ions in them
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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 is a group 1 metal called
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alkali metals
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how much carbon does low-carbon steel contain
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up to 0.25%
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what are acids called
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proton donors as they give away H+ ions
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what does a metal displace in metal and acid reaction
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it displaces the hydrogen in the acid to form a salt, this hydrogen then forms hydrogen gas.
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an indicator turned blue in alkali, name the indicator
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litmus paper
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what is air made of
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78% nitrogen 21% oxygen 0.9% argon 0.04% carbon dioxide 0.4% water vapour (this is an average across all climates) |
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what is source of H+ ions
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acid
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