alcohols, ca, polymers

Question 1

What is fermentation? and a disadvantage.

Answer 1

plant material containing sugars is mixed with water and yeast , enzymes in yeast turn sugars into ethanol and co2.

can’t produce concentrations higher than 15% bc higher concentrations kill yeast cells so u use fractional distilation

Question 2

2 things needed during fermentation process?

Answer 2

1. an air lock to let co2 out but stop o2 coming in because yeast fermentation is an anaerobic process.
   (only occurs in absence of oxygen)
2. correct ph and temps so enzymes can work best

Question 3

using fractional distillation to produce higher concentrations of ethanol?

Answer 3

When a mixture of ethanol and water is
heated it starts to evaporate and rise up
the fractionating column where it cools
and condenses. Ethanol has a lower
boiling point than water, so remains as a
gas for slightly longer and rises slightly
further up the fractionating column.
Therefore the mixture of gases that
reaches the top of the column contains
a greater proportion of ethanol.

Question 4

how are ethane and ethanol diff?

Answer 4

ethanol contains an additional oxygen atom unlike ethane. They are also in diff homologous series.

Question 5

general formula for alcohols?

Answer 5

CnH2n+1OH

Question 6

Why do alcohols have similar chemical properties?

Answer 6

because they all contain one -OH functional group.

Question 7

similar chem properties of alcohols …

Answer 7

1. during cc they produce c02 and h20
2. can be partially oxidised
   to form carboxylic acids

Question 8

what is the oxidation reaction to form ethanoic acid.

Answer 8

ethanol and 02 collide and ethanol loose two hydrogen atoms, the carbon missing the 2 hydrogens forms a double bond with oxygen. the 2 hydrogens atoms from the ethanol combine with 02 molecule to form h20

Question 9

what is ethanoic acid?

Answer 9

a member of the homologous series called carboxylic acids

Question 10

how can a carboxylic acid be made?

Answer 10

formed by gentle oxidation of alcohols using oxidising agents such as hot copper oxide,

Question 11

what are similar chemical properties of carboxylic acids?

Answer 11

• react with metals to form a salt and hydrogen
• react with bases to form a salt and water
• react w carbonates to form a salt, water and co2

Question 12

a polymer is..

Answer 12

a substance of high average relative

molecular mass made up of small repeating units

Question 13

how do ethene molecules combine together in a polymerisation reaction?

Answer 13

poly(ethene) is formed when large no. of ethene monomers join together. The double covalent bond breaks and another ethene monomer joins on.

Question 14

what are some naturally occurring polymers?

Answer 14

some substances such as DNA, starch and proteins

Question 15

list the polymer name, properties and uses for polythene.

Answer 15

poly(ethene)
flexible, cheap, good insulator
plastic bags and bottles, clingfilm

Question 16

list the polymer name, properties and uses for polypropylene.

Answer 16

poly(propene)
flexible, doesn’t shatter
buckets, bowls, rope , carpets

Question 17

list the polymer name, properties and uses for PVC

Answer 17

poly(chloroethene)
tough, good insulator, can be made hard or flexible
window frames, pipes , insulation for elec wires

Question 18

list the polymer name, properties and uses for PTFE

Answer 18

poly(tetrafluoroethene)
tough, slippery,
non-stick coating for frying pans, kitchen utensils, carpets

Question 19

whats condensation polymerisation?

whats a polyester?

Answer 19

monomers join together and eliminate a small molecule such as water

a long - chain molecule that contains many ester links

Question 20

whats the functional group for an ester and how do they form?

Answer 20

-coo-

formed when a carboxylic acid reacts with alcohol in the presence of a catalyst

c.a + alcohol → ester + water

Question 21

suggest why splints are soaked in distilled water before use.

Answer 21

because distilled water contains no ions that will interfere with the test

Question 22

machines can be used to analyse substances, state 3 advantages.

Answer 22

improvement in sensitivity , accuracy , speed

Question 23

why is a flame photometer used?

Answer 23

it measures the light intensity of the flame colours produced by metal ions

Question 24

describe how to carry out a flame test:

Answer 24

1. light Bunsen burner , opening air hole to produce light blue flame
2. pick up small sample of test substance using wire loop
3. hold sample in edge of the flame, observe the flame colour

Question 25

which of these metal ions produce which flame colours?

Lions ruin some young peoples lives cos of crazy brains

Answer 25

lithium ion, Li+ (red)
 sodium ion, Na+ (yellow)
 potassium ion, K+ (lilac)
calcium ion, Ca2+ (orange-red)
copper ion, Cu2+ (blue-green

Question 26

sodium hydroxide can be used to form a couloured preciptate to indicate a metal CATION

iron (II)
iron (III)
copper
calcium 
aluminium

Answer 26

green , brown , blue, white, white

Question 27

how can you identify calcium and aluminium further?

Answer 27

add excess sodium hydroxide solution
 no change with calcium hydroxide 
 precipitate; aluminium hydroxide 
precipitate dissolves; to produce a 
colourless solution.

Question 28

how to test for carbonate ions? NEG

Answer 28

add dilute hydrochloric acid, look for bubbling caused by co2, do a confirmatory test , if bubbles have co2, turn limewater milky

Question 29

test for sulfate ions?

Answer 29

few drops hydrochloric acid to acidify solution & removes carbonate ions that might also form precipitate , few drops barium chloride , white precipice of bc forms if theres sulfate ions

Question 30

test for halide?

Answer 30

few drops dilute nitric acid , acidifies colution & removes carbonate ions , few drops silver nitrate solution. Chloride = white p, bromide = cream , iodide = yellow

Question 31

what are ceramics? List properties.

what are some examples?

Answer 31

a range of durable compounds that change very little when heated
chemically unreactive, high mp ,brittle , poor elec conductors ,
brick , porcelin, china they are giant structures

Question 32

composite materials? eg

compressive strength?

Answer 32

mixture of 2 or more materials. concrete

how well a material resists being squashed

Question 33

nanoparticles?

nanoparticulate?

Answer 33

a bulk materials (lumps and powders) consist of a huge no. of atoms. Nanoparticles consist of a few hundred (1-100nm) in size

substances consisting of nanoparticles.

Question 34

why are nanoparticles used in sunscreens?

Answer 34

titanium dioxide

np. absorb UV light

Question 35

why are np useful for catalysts

Answer 35

they have a large surface area : volume

Question 36

risks of np.

Answer 36

damage to human health, may catlyse harmful reactions. usues of np materials havent been out for long tho.