Stuff from chem revision booklet

Question 1

equation for rate of reaction

Answer 1

rate of reaction = change in amount of a reactant or product/time
or
number of successful collisions / time

Question 2

ways to measure how long it takes for a reaction to finish

Answer 2

how long it takes for…
cross to dissapear (solid sulfur precipitate)
magnesium piece to dissapear
how long it takes to produce a certain amount of gas (?)

Question 3

if the reaction is exothermic, will the triangle H have a negative sign?

Answer 3

yess

Question 4

advantages and disadvantages of ethene route to alcohol

Answer 4

fast, efficient, continuous process,relatively pure product
non renewable finite resource

Question 5

disadvantages and advantages of fermentation

Answer 5

cheap and renewable resource (eg sugar cane)
slow reaction, poor quality products- eg low aqueous concentration <14%

Question 6

industrial formation of ethanol

Answer 6

made from ethene and steam
high temp, high pressure and phosphoric acid catalyst needed
ethene combines with steam to make ethanol which is used as a solvent

Question 7

process of fermentation

Answer 7

sugar solution + yeast warmed
airlock keeps air out
yeast respires anaerobically, releasing enzymes to catalyse the breakdown
C6H12O6 -> 2C2H5OH + 2CO2

Question 8

what is polypropene used for

Answer 8

for plastic crates and ropes, as it is stronger and less flexible than polyehtene

Question 9

what is polyethene used for

Answer 9

plastic bags and plastic bottles- forms a thin, flexible, transparent film

Question 10

what is polytetrafluorene used for

Answer 10

non stick pans

Question 11

what is PVC used for

Answer 11

drain pipes and insultion on electric cables since it is strong, not flexible and doesn’t conduct electricity

Question 12

how do you calculate RF value

Answer 12

distance travelled by component/ distance travelledby solvent

Question 13

substance + oxygen ->

Answer 13

oxide

Question 14

metal + water ->

Answer 14

metal hydroxide + hydrogen

Question 15

metal + acid->

Answer 15

salt+hydrogen

Question 16

oxide + acid ->

Answer 16

salt+water

Question 17

hydroxide+acid->

Answer 17

salt+water

Question 18

carbonate+acid->

Answer 18

salt+water+co2

Question 19

hydrogencarbonate+acid->

Answer 19

salt+water+co2

Question 20

ammonia+acid->

Answer 20

ammonium salt

Question 21

metal carbonate->

Answer 21

metal oxide+co2

Question 22

precautions for toxic substances

Answer 22

wear gloves
if gas, use fume cupboard/well ventilated lab

Question 23

precautions for corrosize substances

Answer 23

wear gloves to prevent burns

Question 24

precautions for harmful substances

Answer 24

wash hands if spilt

Question 25

precautions for irritant substances

Answer 25

wear gloves or wash hands if spilt

Question 26

precautions for flammable substances

Answer 26

keep away from naked flames

Question 27

precautions for oxidising agents

Answer 27

do not mix with easily flammable substances

Question 28

what is an oxidising agent?

Answer 28

allows other substances to burn well, will oxidise other substances

Question 29

precautions for explosive substances

Answer 29

do not use

Question 30

example of an explosive substance

Answer 30

caesium

Question 31

precautions for environment damaging substances

Answer 31

do not flush down sink put waste in a container to be disposed of professionally

Question 32

name two flammable gases

Answer 32

hydrogen and methane

Question 33

hydrogen and methane are...

Answer 33

flammable gases

Question 34

When concentrated, acids and alkalis...

Answer 34

corrosize and can chemically burn skin

Question 35

halogens such as chlorine are...

Answer 35

toxic their vapours are poisonous

Question 36

organic chemicals like ethanol are..

Answer 36

flammable, should be kept away from naked flames

Question 37

what did JJ thompson do?

Answer 37

passed electricity thru low pressure gas tube neg electrode emitted beam of neg charged particles. realised they must've come from inside the atom possible bc electricity

Question 38

when did JJ thompson discover electrons?

Answer 38

late 1800s

Question 39

when was the existance of the neutron confirmed?

Answer 39

1932

Question 40

who confirmed the existance of the neutron?

Answer 40

james chadwick

Question 41

what did james chadwick do?

Answer 41

confirm existance of neutron in 1932

Question 42

relative mass of an electron?

Answer 42

1/1860

Question 43

what happened in 1911?

Answer 43

rutherford concluded positive stuff in atoms must be concentrated in a very small nucleus discovery possible due to radioactivity

Question 44

who first suggested that things were made of atoms?

Answer 44

democritus ancient greek times

Question 45

what did john dalton propose?

Answer 45

matter is composed of tiny particles called atoms atoms of a similar element are alike in shape, size and weight but differ from other elements during chemical changes atoms of different elements unite forming molecules when atoms combine they do so in definite whole number ratios

Question 46

when was john dalton?

Answer 46

early 1800s

Question 47

what is ionic bonding?

Answer 47

complete transfer of one or more electrons from metal to non metal, giving charged ions that electrostatically attract

Question 48

what is a covalent bond?

Answer 48

the electrostatic attraction between positively charged protons in the nucleus and the negative shared pair of electrons

Question 49

What is the structure of metals?

Answer 49

Layers of pos close packed metal ions in "sea" of delocalised electrons

Question 50

Why are metals malleable?

Answer 50

Layers of ions can slide over each other

Question 51

Why do metals have high MPs?

Answer 51

v. strong electrostatic attraction between ions+delocalised electrons lots of energy to overcome

Question 52

Why do simple molecular substances have low BPs?

Answer 52

only weak IMF between the molecules these take little energy to overcome

Question 53

why can't molecular compounds conduct electricity?

Answer 53

no charged particles that can move

Question 54

strcture of diamond/graphite

Answer 54

giant lattice of atoms

Question 55

why do giant covalent structures have high MPs?

Answer 55

many strong covalent bonds between all the atoms that take a lot of energy to break

Question 56

why do some ionic compounds have higher MPs than others?

Answer 56

the higher the charge the stronger the attraction

Question 57

How do you calculate the volume of a gas? (dm^3)

Answer 57

moles x 24

Question 58

Limitations of dot cross representation?

Answer 58

Doesn't show relative size of atoms or shape of molecule - covalent does not show how the ions are arranged in a lattice - ionic

Question 59

Limitations of ball-and-stick representation?

Answer 59

atoms not to scale do not show where the electrons in the bond come from makes it look like there are large gaps between atoms ^^ covalent

Question 60

Limitations of space filling representation?

Answer 60

not always easy to see the 3D shape

Question 61

Limitations of displayed formula representation?

Answer 61

doesn't show 3d shape or correct bond angles

Question 62

Limitations of close packed representation?

Answer 62

difficult to see arrangement of ions

Question 63

limitations of ionic 2d ball and stick

Answer 63

doesn't show 3d arrangement

Question 64

limitations of ionic 3d ball and stick

Answer 64

the ions are actually close together gives a false image of bond direction; it is only electrostatic attraction