Principles of Chemistry

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Relative mass and relative charge of electrons, protons and neutrons?
electrons: 1/200 mass, -1 charge. proton: 1 mass, +1 charge. neutron: 1 mass, 0 charge.
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whats the mass and atomic number?
mass number (top number) is the total number of protons and neutrons. The atomic number (bottom) is the number of protons.
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Describe diffusion experiment with potassium and water.
potassium manganate is bright purple, take beaker of water, put potassium manganate at bottom, the purple colour slowly spreads to whole beaker.
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describe ammonia and hydrogen chloride experiment which shows diffusion
Ammonia gives off ammonia gas, hydrochloric acid gives off hydrogen chloride gas. Cotton wool soaked in each solution at either side of closed test tube. They react to form ammonium chloride (white ring).
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Where does the ring of ammonia form and why?
nearer the hydrochloric acid side because the particles of ammonia are smaller and lighter.
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Describe the bromine gas and air diffusion experiment.
bromine gas is brown and strong smelling, fill half a gas jar full of bromine gas and the half full of air - sperate the gases with a glass plate. When the glass plate is removed the brown bromine gas diffuses through air.
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What is filtration used for?
to seperate an insoluble solid from a liquid.
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What is crystallisation used for?
to separate a soluble solid from a solution.
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How do you crystallise a product?
poor solution into evaporating dish, slowly heat solution, some solvent will evaporate and the solution will become more concentrated. stop heating when crystals start to form. wash andleave dish in warm place for solvent to evaporate.
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How to separate rock salt using filtration and crystallisation?
1.) grind up rock salt with pestle and mortar. 2.) Dissolve in beaker ad stir. 3.) Filter through filter paper in a funnel. 4.) Evaporate in a evaporating dish.
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How to do paper chromatography?
draw pencil line near bottom of filter sheet paper. add spots of different dyes to the line. role up paper and put in solvent. put lid on top to stop evaporation. solvent seeps up paper taking dye too. each dye moves up at different speeds.
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what do you learn from the paper chromatography experiment?
the faster the dye goes, the faster that dye would dissolve.
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In paper chromatography, if dyes are at the same place what does that mean?
they are the same dye.
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How to do simple distillation? what could you use it for?
solution is heated, some will evaporate, the vapour is cooled, condensed and is collected. to purify sea water. it can only separate things with different boiling points.
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what is fractional distillation?
the separation of a mixture of liquids.
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How to do fractional distillation? 1
put mixture in flask, stick a fractioning column on top the heat. the different liquids evaporate at different temps so have different boiling points. liquid with lowest boiling points evaporate first. it will reach top of column.
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How to do fractional distillation? 2
liquid with lowest boiling points evaporates first. It will reach the top of the column. liquids with hight boiling points may all start to evaporate but the column is cooler towards the top so they'll only get part of the way before condesing and
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fractional distillation 3?
running back down towards the flask. when the first ones been collected, rasie the temp until next one reaches the top.
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OILRIG?
oxidation is loss, reduction is gain.
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cations group one and group 2?
Li+. Na+. K+. Be2+. Mg2+. Ca2+.
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anions group six and 7?
O2-. S2-. F-. Cl-. Br-.
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What happeneds when cations meet up with any of the anions?
they attract eachother to form ionic compound.
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Whats the attraction like with ionic bonding?
strong, electrostatic attraction, high melting and moiling point.
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3 points about simple molecular structure?
atoms within molecule are held together by strong covalent bonds. the forces of attraction between the molecules are very weak so the melting and boiling points are low as molecules are easy to pull apart.
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5 points about giant covalent structures
similar to giant ionic structures except there are no charged ions. all atoms are bonded to each other by strong covalent bonds. so it takes a lot of energy to break them so giant covelant structures have high melting points and boiling points.
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do giant covelant structures conduct electricity? are they insoluble? 2 examples.
diamond, graphite. dont conduct electicity when molten, insoluble in water.
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Covalent bonding (DOT AND CROSS DIAGRAMS) is sharing pairs of electrons with other atoms, whats the attraction like?
strong attraction between shared electrons and the nuclei of atoms involved.
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Why dont solid ionic compounds conduct electricity?
ions arn't free to move. when an ionic compound is dissolved the ions seperate and are free to move in solution so they'll carry an electric current, so conduct electricity.
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why dont covalent compounds conduct electricity?
they dont contain ions becaue they make bonds by sharing electrons. so they dont have any charge carriers that are free to move so can't carry electric current.
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3 points about metals and metalic bonding.
metals have giant structure of positive ions. the attraction between the positive ions and the electrons is called metallic bonding. metallic bonding gives the metals their properties.
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why are metals good conductors of electricity and why are they malleable?
free electrons carry current and heat energy through material, layers of atoms in a metal can slide over each other.
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6 points about electrolysis.
if you pass an electric current through a ionic substance that's moltern or in solution it breaks down into new substances < electrolysis. requires liquid to conduct electricity < electrolyte, made by melting or dissolving ionic compounds.
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In electrolysis where are electrons taken from and to?
electrons are taken from ions at positive electrode (anode) and given to other ions at negative electrode.
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what do all solid salts consist of?
a lattice of positive and negative ions.
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The water in a lattice is called water of crystallisation whats the difference between hydrated and anhydrous?
a solid containing water of crystallisation is hydrated. If a salt doesnt contain any water of crystallisation its called anhydrous.
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How do you calculate how much water of crystallisation a salt contains?
work out what mass of substance you have. calculate no. of moles of water lost. calculate no. of moles of anhydrous salt made. work out ratio of moles to anhydrous salt to moles of water.
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concentration moles per dm formula?
concentration= no of moles divided by volume/1000
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how to change concentration moles per d to grams dm?
times by mr
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how to calculate mass in reaction?
write out balanced equations, for the 2 bits wanted, work out mr, x them by balancing numbers in equation. divide to get one, multiply to get all.
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moles =?
mass over mr
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how to find relative atomic mass?
x the mass of each isotope by it's relative abundance, add those together, divide by the sum of the relative abundances
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difference between molecula and empirical formula?
empircal formula of a compound is the simplest form, tells you ratio of different elements. the molecular tells you actual number of atoms in each element in a single molecule.
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how to find molecular formula from empirical formula?
You need to find the Mr of the empirical formula 2. See if the Mr of the molecular formula is 1x, 2x, 3x etc the empirical formula. 3. If it is 3x then 3x each of the atoms. - the Mr of this compound should be the same as the Molecular Mr given.
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Other cards in this set

Card 2

Front

whats the mass and atomic number?

Back

mass number (top number) is the total number of protons and neutrons. The atomic number (bottom) is the number of protons.

Card 3

Front

Describe diffusion experiment with potassium and water.

Back

Preview of the front of card 3

Card 4

Front

describe ammonia and hydrogen chloride experiment which shows diffusion

Back

Preview of the front of card 4

Card 5

Front

Where does the ring of ammonia form and why?

Back

Preview of the front of card 5
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