seperate chemistry 2

Question 1

Flame tests

Answer 1

First clean a nichrome wire loop by dipping in hydrochloric acid then rinse in distilled water
Dip wire in sample of substance and put in blue part of flame
record what colour flame turns

Question 2

Flame test result for Lithium

Answer 2

red

Question 3

Flame test result for sodium

Answer 3

yellow

Question 4

Flame test result for pottasium

Answer 4

lilac

Question 5

Flame test result for calcium

Answer 5

orange-red

Question 6

Flame test result for copper

Answer 6

blue-green

Question 7

Precipitate test

Answer 7

Many metals are insoluble and precipitate out of solution when formed. Some take a characteristic colour
First add drops of sodium hydroxide solutiom.
If a hydroxide precipitate forms, you can use its colour to tell which ion was in compound

Question 8

What substances do we use in precipitate test

Answer 8

Aluminium
calcium
copper
Fe(II)
Fe(III)

Question 9

Precipitate colour that forms in aluminium

Answer 9

white but redisolves in excess NaOH

Question 10

Precipitate colour that forms in calcium

Answer 10

white

Question 11

Precipitate colour that forms in copper

Answer 11

blue

Question 12

Precipitate colour that forms in Fe(II)

Answer 12

green

Question 13

Precipitate colour that forms in Fe(III)

Answer 13

brown

Question 14

What happens when you add NAOH to Ammonium ions

Answer 14

Produces ammonia

Question 15

how do you test for ammonia

Answer 15

holding damp red litmus paper over it

Question 16

Tests for Anions

Answer 16

Test for Halides using silver Nitrate solution.
Test for Carbonates using dilute acid
Test for Sulfate ions using Barium Chloride solution

Question 17

Test for Halides

Answer 17

Chloride, bromide, iodide
Add some dilute nitric acid followed by a few drops of silver nitrate solution.

Question 18

Halide test result for chloride

Answer 18

white precipitate of silver chloride

Question 19

Halide test result for bromide

Answer 19

Cream precipitate of silver bromide

Question 20

Hallide test result for iodide

Answer 20

yellow precipitate of silver iodide

Question 21

Test for Carbonates

Answer 21

add some dilute acid
if carbonate solution present the mixture should fizz because a reaction causes carbon dioxide gas to be produced.
You can check if it is carbon dioxide by bubbling it throughlimewater. and it turns milky

Question 22

Test for sulfate ions

Answer 22

first add dilute hydrochloric acid- this stops any preciptation reactions not involving sulfate ions to take place

Then add barium chloride solution.
if present white precipiate of barium sulfate forms

Question 23

how to work out the different ions in a solution

Answer 23

using flame photometry
using machines

Question 24

using machines

Answer 24

very sensitiv
very fast
very accurate

Question 25

how can you test for a alkene

Answer 25

Using bromine water. when sahken together an alkene will decolourise water, turning it from ORANGE to COLOURLESS. This is because and addition reaction takes place where bromine is added accross the alkene double bond

Question 26

alkenes and alkanes burn in oxygen in combustion reaction

Answer 26

the products are carbon dioxide and water

Question 27

properties of different polymers of polymers

Answer 27

poly(ethene)- flexible, electrical insulator, cheap poly(propene)- flexible, strong, tough, mouldable poly(chloroethene) (PVC)- tough, cheap poly(terafluroroethene) (PTFE) - unreactive, tough, non-stick

Question 28

uses of poly(ethene)

Answer 28

plastic bags, bottles, wire insulator

Question 29

uses of poly(propene)

Answer 29

crates, furniture ropes

Question 30

uses of PVC

Answer 30

window frames, water pipes

Question 31

uses of PTFE

Answer 31

non-stick pans, waterproof clothing

Question 32

naturally occuring polymers

Answer 32

DNA- made up of nucleotide monomers Amino acids monomers form protien via condensation plymerisation, carbohydrates

Question 33

Polyesters

Answer 33

are condesation polymers. Polyesters form when dicarboxylic and diol monomers react together Dicarboxylic monomers contain two carboxylic acid (-COOH) groups and diol monomers contain two alcohol (-OH) groups when the two bond forms an ester link you get an ester and water (pick out H2O molecules

Question 34

how do you make ethanol

Answer 34

fermentation using yeast to convert a type of carbohydrate called sugar into a alcahol yeast contains enzymes. 1) mix yeast and solution of a carbohydrate 2) keep the mixture between 30 and 40 degrees- fermentation happens faster betweeen these temperatures. 3) keep mixture in anaerobic conditions (no oxygen) as oxygen converts the ethanol to ethanoic acid 4)when concentration of alcahol gets to 10 to 20% the reaction stops as the yeast is killed. 5) yeast will fall to bottom of the container

Question 35

how do you increase the concentration of ethanol

Answer 35

Using fractional distillation Heat ethanol till evaporates (ethanol has a lower boiling point then water) gas rises and funneled into tube condenser condenses the gas into stronger concentration ethanol

Question 36

devise experiment to investigate the difference in how alcahols heat up water

Answer 36

1) put some alcahol in a spirit burner and measure the mass of the burner and fuel using a mass balance 2) measure 100cm3 distilled water into copper calorimeter 3) insulate cariometer by using a draught excluder, then cover with an insulating lid 4) take initial temperature of water 5) stir water throughout, when water ruses to 20 degrees blow out alcahol 6) immediatly reweigh the burner and fuel 7) repeat the experiment using another alcahol