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universal indicator alkali

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Chemistry

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1

universal indicator alkali

blue/purple

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2

universal indicator acid

red

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3

element which forms a basic oxide

copper

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4

bromine at room temp

red-brown liquid

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5

chlorine at room temp

yellow-green gas

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6

iodine at room temp

grey solid

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7

rf equation

distance moved by substance/distance moved by solvent

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8

obtain pure dry crystals from salt solution

heat to evaporate water,

leave to cool,

filter to obtain crystals,

leave to dry (oven)

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9

diamond electricity

does not conduct electricity as no free electrons

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10

diamond melting point

very high as strong covalent bonds in rigid structure

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11

diamond uses

cutting tools as very hard

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12

graphite electricity

conducts electricity as contains delocalised electrons free to move

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13

graphite melting point

high as contains lots of strong covalent bonds

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14

graphite uses

lubricant as layers can slide over each other

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15

diamond and graphite structure

giant covalent structures

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16

diamond structure

tetrahedral

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17

graphite structure

hexagonal

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18

why ionic compound has high melting point

giant structure, strong electrostatic attraction between oppositely charged ions so large amount of energy needed to break bonds

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19

forces of attraction in covalent bond

sharing of electrons between two attracted nuclei

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20

half equation for formation of oxygen during electrolysis

4OH- = O2 + 2H2O + 4e

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21

why do ionic compounds need to be molten to conduct electrolysis

when solid, ions arent free to flow and conduct charge but when molten are mobile

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22

why metals are malleable

layers of atoms which can slider over eachother

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23

what happens at anode

oxidation, loss of electrons

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24

what happens at cathode

reduction, gain of electrons

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25

percantage change

change/original x 100

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26

why use powder

larger surface area so reacts quicker

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27

why is argon unreactive

full outer shell so doesnt lose or gain electrons

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28

percentage of oxygen in air

21%

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29

what forms acid rain

nitrogen dixoide and water (nitric acid), or sulfur dioxide and water (sulfuric acid)

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30

magnesium and oxygen observation

bright white flame, formation of white powder

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31

test for carbon dioxide

bubble through limewater and turns cloudy

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32

variables to be controlled

concentration of acid, surface area of metal, temperature, volume of acid,

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33

percentage of nitrogen in air

78%

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34

percentage of argon in air

1%

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35

percentage of carbon dioxide in air

0.04%

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36

colour of methyl orange

yellow in alkali, red in acid

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37

method to produce dry crystals of hydrated

add powder to acid until powder is in excess,

filter off excess,

heat to evaporate water,

cool,

filter crystals,

leave in warm place to dry

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38

phenolphthalein colours

colourless in acid, pink in alkali

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39

titration method

use pipette to add 25cm3 of acid to conical flask,

add a few drops of indicator,

add acid to burette and record initial reading,

drop acid into flask and swirl continuously until it changes colour,

take final burette reading and find volume of acid needed by working out the difference,

repeat to get concordant results

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40

why is the reaction exothermic in terms of bonds

more energy is given out when bonds are made than is when taken in when bonds are broken

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41

why is soot formed

incomplete combustion due to limited oxygen supply

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42

soot name

carbon

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43

heat energy equation

q x c x temp change

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44

why is volume collected less than expected

gas escaped before bung is placed on flask

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45

why is measuring cylinder not necessary

acid is in excess so an accurate measurement isnt needed

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46

dynamic equilibrium

position in a reversible reaction where the concentration of reactants and products remain constant and the forward and backward reactions continue to occur

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47

pressure increase effect on equilibrium

moves to direction of fewer molecules of gas

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48

concentration increase effect on equilibrium

moves away from what gained more conc

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49

temperature increase effect on equilibrium

moves in endothermic direction

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50

catalyst effect on yield

none as increases rate of both backwards and forwads reaction

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51

catalyst effect on rate of reaction

provides alternate pathway so lower activation energy needed for reaction to begin, meaning more collisions so speeds up rate of reaction

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52

yield change depending on equilibrium

if equilibrium shifts to the right the yield of products will increase

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53

test for chlorine

damp litmus paper goes from red to white

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54

test for ammonia

turns red litmus paper blue

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55

lithium flame test

crimson

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56

potassium flame test

lilac

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57

calcium flame test

orange-red

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58

sodium flame test

yellow

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59

copper flame test

blue-green

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60

iron 3 hydroxide colour

brown

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61

iron 2 hydroxide colour

green

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62

copper hydroxide colour

green

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63

test for halides

silver nitrate + nitric acid

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64

test for sulfates

barium chloride + hydrochloric acid

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65

positive result for sulfate

white precipitate

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66

test for water

white copper 2 sulfate turns blue, cobakt 2 chloride strips turn pink

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67

test for pure water

boils at 100*C or melts at 0

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68

products of incomplete combustion of an alkane

carbon monoxide, water

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69

general formula for alkene

CnH2n

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70

unsaturated meaning

contains a double bond

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71

test that a hydrocarbon is unsaturated

add bromine solution and it will turn from orange to colourless

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72

enthalpy change equation

heat energy/moles

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73

why crack long chains into short ones

short chains are more useful and have a higher demand

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74

solid to gas change

sublimation

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75

test for copper and iron 2

add sodium hydroxide solution, if blue precipitate forms copper is present, if green precipitate forms iron is present

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76

test for chloride and bromide

add silver nitrate, if white precipitate forms chloride is present, if cream precipitate forms bromide is present

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77

test to distinguish between alkane and alkene

bromide solution stays orange for alkane, and becomes colourless for alkene

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78

ionic bond

electrostatic attraction between oppositely charged atoms

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79

why is it not safe to heat alcohol in an evaporating basin with a bunsen burner

they are flammable

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80

properties of aluminium

high mp, resistant to corrosion, good conductor of thermal energy

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81

why is fermentation of ethanol anaerobic

ethanol would react with oxygen to make ethanoic acid

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82

equation for complete combustion of ethanol in air

C2H5OH + 3O2 = 2CO2 + 3H2O

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83

conditions for making ethanol with steam

300*C, 60-70 atm

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84

dynamic equilibrium

state where a reaction is taking place in both reactions at the same rate at the same time

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85

mol equation for mol/vol topic

vol/24000cm3

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86

why is pencil line below water line

so inks dont mix with water

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87

hydrogen qualities

flammable, low density

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88

isomer

compound with the same molecular formula but different structural formula

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89

exothermic energy profile

products below reactants

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90

bond breaking

endothermic, needs heat energy

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91

bond making

exothermic, releases heat energy

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92

problem with disposal of addition polymers

landfill sites getting full, greenhouse gases produced when burned

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93

lower hydrocarbon qualities in crude oil

darker colour, higher boiling point, high viscosity

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94

why is carbon monoxide poisonous

reduces capacity of blood to transport oxygen

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95

complete combustion of hydrocarbon products

carbon dioxide + water

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96

crude oil fractions top to bottom

gases, petrol, kerosene, diesel oil, fuel oil, bitumen

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97

crude oil rhyme

good penguins keep diving for bass

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98

chemical test for water

anhydrous copper sulfate turns from white to blue

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99

reactivity trend down group 7

gets less reactive as you go down

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100

combustion of hydrogen in air

2H2 + O2 = 2H2O

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