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25 Cards in this Set
- Front
- Back
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Percentage mass of an element in a compound |
Ar X number of atoms of that element ------------------------------------------------------ x100 Mr of the compound |
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Avogadro's constant |
6.02x10^23 |
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Number of moles |
Mass in grams ---------------------- Mr (of the element or compound) |
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Balance equations using reacting masses |
Divide the mass of each substance by its relative formula mass to find molesDivided moles by the smallest molesIf numbers not whole treat them as ratios Put numbers Infront of equation Divided moles by the smallest moles molesDivided moles by the smallest molesIf numbers not whole treat them as ratios Put numbers Infront of equation If numbers not whole treat them as ratios Put numbers Infront of equation |
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What is the limiting reactant |
The reactant that's used up in a reaction. The amount of product formed is directly proportional to the amount of limiting factor. |
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Working out the amount of product needed |
Write out balanced equation Work out Mr of reactant and product u want Find how many moles there are of the substance u know Use the balanced equation to work out how many moles there will be of the other substance Use this number of moles to calculate mass |
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Concentration g/dm3 |
Mass of solute g /volume of solvent dm3 |
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Ph probe |
Measures ph ( the concentration of H+ ions in the soloution) |
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Describe acids |
Substance that forms aqueous Soloutions with a pH of less then 7 Form H+ ions in water |
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Describe bases |
Substance with a pH greater then 7 |
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Describe alkalis |
Base that dissolves in water to form a solution with a pH greater then 7 Form OH- ions in water |
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Neutralisation |
Acid + base - salt + water H+ + OH- - H2O Products are neutral |
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Metal oxides and hydroxides which dissolve in water are |
Soluble compounds that are alkali |
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Metal oxide and hydroxide neutralisation reaction |
Acid +metal oxide - salt + water Acid + metal hydroxide - salt + water |
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Metal carbonates are also |
Bases. They react with acid to produce a salt water and carbon dioxide |
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Metal carbonates reaction |
Acid + metal carbonate - salt + water + carbon dioxide |
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How do you make soluble salts |
Using an insoluble base. Pick right acid and insoluble base. Eg copper chloride could be made mixing hydrochloric acid and copper oxide Warm the dilute acid using Bunsen burner Add insoluble base to the acid a bit at a time untill no more reacts (base is in excess) Filter out the excess solid to get salt soloution Then use crystilation and dry salts |
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Acid + metal |
Acid +metal - salt + hydrogen (Or with water can be used to show how reactive it is) |
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Metal + water |
Metal + water - metal hydroxide + hydrogen |
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Reduction with carbon |
The ore is reduced and carbon is oxidised |
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If is to reactive for carbon what happens |
Electrolysis |
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In displacement reactions what happens to metal ion and metal atom |
Metal ions gains electrons and is reduced Metal.atom loses electrons and is oxidised. |
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Describe electrolysis |
An electric current passed through an electrolyte, molten ionic compound, ions move toward the electrodes were they react and decompose . Positive ions in electrolyte move to the cathode whilst negative ions move towards the anode. They form the uncharged element and are discharged from the electrolyte |
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Electrolysis of aqueous solutions |
As well as ions from the ionic compound there will be hydrogen ions , hydroxide ions from the water. At the cathode if H+ ions and metal ions are present hydrogen gas will be produced If the metal ions form an elemental metal that is more reactive then hydrogen. If the metal ions form an elemental metal that is less reactive then hydrogen (e.g. copper ions )a solid layer of the pure metal will be produced instead At the anode if OH- and halide ions are present, molecules of chlorine , bromine or iodine will be formed. If no halide ions are present then the OH- ions are discharged and oxygen wil be formed. |
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Chlorine hydrogen and oxygen test |
Chlorine bleached damp litmus paper white Hydrogen makes a squeeky pop with a lighted splint Oxygen will relight a glowing splint |
