a chemical formula showing the ratio of elements in a compound rather than the total number of atoms -find number of moles and divide by smallest number
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molecular formula
actual number of atoms -find empirical mass and divide rfm by it
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Avogadro constant
in 1 mole of a substance, there are 6.02 x 10^23 particles of the substance
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Percentage yield
Actual yield/ theoretical yield x 100
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theoretical yield
Add the R.F.M
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Atom economy
R.F.M useful products / R.F.M of reactants x 100
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Concentration in mol dm3
Number of moles in solute / volume of solute dm3
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Concentration in mol dm3
Concentration gmd3 / r.f.m solute
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Rf
distance substance travels from origin/ distance solvent travels from origin
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Amount of gas mol
Vol of gas / molar vol (24dm3)
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metal + water →
metal hydroxide + hydrogen
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Metal + Acid
Salt + Hydrogen
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ionic bond
Formed when one or more electrons are transferred from one atom to another, metal + non metal Do not conduct as solid but as liquid or dissolved conduct High melting point: strong electrostatic bonds between ions Soluble in water: water molecules slight electrical charge, attracting ions away from the lattice
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covalent bond
a bond formed when atoms share one or more pairs of electrons, non metal + non metal Molecular solids: low melting ans boiling points however larger solid stronger molecular forces
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Graphite
Only three out of four electrons in carbon involved so can conduct electricity and soft and slippery, lube, malleable
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Diamond
Massive covalent High melting + boiling Can't conduct electricity V hard
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metallic bonding
a bond formed by the attraction between positively charged metal ions and the electrons around them, giant lattice w delocalised electrons\=conduct Malléable: sea of electrons slide over each other High melting point: string bonds
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Smart alloy
Metal that changes shape depending on temperature
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Allotrope
Different structural forms of the same element
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What is pH?
the measure of the hydrogen ion concentration in a solution. If you decrease the concentration of H+ ions by a factor of 10 the ph increase by 1
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Strong acids
Fully dissociate into H+ ions
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Acid + Base
Salt + Water
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Acid + Carbonate
Salt + Water + Carbon Dioxide
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concentrated solution
a solution containing a large amount of solute dissolved in small amount of solvent
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Bases
Bases neutralise acids. They are hydrogen ion acceptors. When they react, they accept H+ions.
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Acids
Acids are hydrogen ion donors. When they react, they release H+ ion(s).
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soluble in water
sodium, potassium, and ammonium compounds, nitrates, MOST chlorides, MOST sulfates
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insoluble in water
Silver lead carbonates, lead barium calcium sulfate, MOST carbonates, MOST hydroxides
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Reactivity series
Potassium sodium calcium magnesium aluminium Carbon zinc iron lead Hydrogen copper silver gold
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Anodes
Electrodes where oxidation occurs, anions (negative ions) go, positive, non metals, oxygen forms
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Cathode
Reduction, negative, cations (positive ions) go, metals, hydrogen forms
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Ore
a rock that contains a large enough concentration of a mineral making it profitable to mine
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METHODS OF EXTRACTION
Higher than carbon: electrolysis Lower than carbon: displacement reaction with carbon
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Bioleaching
Process of extraction of metals from ores using microorganisms. Bacteria produce solution called a leachate where copper extracted via displacement and purified by electrolysis
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Phytoextraction
The process by with plants exact metals from soil or water and store them above ground. Burnt to get the element
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Equilibrium
Increase of temperature exothermic direction (to the right) Increases of pressure favours reaction which produces less moles (to the right)
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Haber process
450 dégrées, 200 atmosphères, iron catalyst
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Properties of transition metals
-malleable -good conductors of electricity -high melting points - high densities - typically show catalytic activity
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Fermentation Advantages
-made from renewable carbohydrates -lower temperature -low pressure HOWEVER ITS SLOW AND PRODUCT IS IMPURE