Chemistry S3 Revision 2017

Question 1

What are the seven separation techniques?

Answer 1

The seven separation techniques are:

Heating

Distillation

Electrolysis

Filtration

Chromatography

Magnetism

Evaporation

Question 2

What is RF values in chromatography?

Answer 2

RF distance moved by the compound ÷ distance moved by the the solvent.

The RF value of a particular compound is always the same - if the chromatography has been carried out in the same way.
This allows industry to use chromatography to identify compounds in mixtures.

Question 3

What is the reactivity of metals?

Answer 3

If an acid is added to a metal the metal will be quickly corroded by the acid.
We can see a reaction happening because the mixture fizzes and the metal eventual disappears.

Some metals like gold are so unreactive that nothing will happen.

Question 4

What is the reactivity series?

Answer 4

The order of the reactivity series is:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Carbon

Zinc

Iron

Lead

Hydrogen

Copper

Silver

Gold

Platinum.

Question 5

What is the poem for the reactivity series?

Answer 5

Postman
Sends
Cards (with)
Money
And 
Coins 
(to the)
Zoo 
in
Liverpool
His 
Coins (were)
Silver
Gold
Platinum.

Question 6

What is electrolysis?

Answer 6

Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity. During electrolysis metals and gases may form at the electrodes.

Question 7

What is neutralisation?

Answer 7

Neutralisation is the process where an acid (PH 1-6) neutralises an alkali (PH 8-14) to form an neutralised substances (PH7).

All acids contain Hydrogen

This can be tested using the squeaky pop test.

All alkalis contain oxygen + hydrogen.

This can be tested using the re- light spill.

Question 8

What are acids and alkalis measured on?

Answer 8

Acids and acids are measured on a PH scale.

Question 9

What’s the solute?

Answer 9

The solute is the solid that is added to the solvent.

Question 10

What’s the solvent?

Answer 10

The solvent is the liquid the solute is added to.

Question 11

What’s the solution?

Answer 11

The solution is the dissolved mixture of the solute and solvent.

Question 12

What is a displacement reaction?

Answer 12

A displacement reaction is where a more reactive metal displaces (pushes out) a less reactive metal from its compound.

Question 13

What does the atomic structure contain?

Answer 13

Atoms are neutral- they have no charge overall because they have the same number of protons as electrons.

The atomic number tells you how many protons there are.

Question 14

What is a Chromatogram

Answer 14

A Chromatogram is a visible record (such as a graph) showing the result of separating the components of a mixture by Chromatography.

Question 15

What is chromatography?

Answer 15

Chromatography can be used to separate mixtures of coloured compounds. Mixtures that are suitable for separation by chromatography, include inks, dyes and colouring agents in food.

Question 16

What are empirical formulas?

Answer 16

Empirical formulas are used to work out the ratio of elements in a compound, in order to be able to write a formula.

Question 17

What are flame tests?

Answer 17

They are used to detect the presence of a particular metal ion in compound.

Metal ions change the colour of a flame when they are heated in it.

Different metal ions give different ions give different colours, to the flame.

Question 18

How would you carry out a typical flame test?

Answer 18

This is how you would carry out a typical flame test:

Dip a clean flame test loop in the sample solution.

Hold the flame test loop at the edge of a bunsen burner flame.

Observe the changed of the flame and decide which metal it indicates.

Clean the loop in acid and rinse with water, then repeat steps in 1 to 3 with a new sample.

Question 19

Who is the first inventor of the periodic table?

Answer 19

1) Antoine Lavaiosier- French.

In the Periodic Table he put:

Light, Heat

Magnesium oxide- all not an element.

Question 20

Who is the second inventor of the periodic table?

Answer 20

2) Johann Dobereiner- German

He put in a group of tried elements:

Lithium- Li

Potassium- K

Sodium- Na.

Question 21

Who is the third inventor of the periodic table?

Answer 21

Dimiti Mendeleev- Russian

He was the ‘father of the periodic table’. He also made the original periodic table.

Atomic mass corresponded into relative molecular mass.

He used estimated patterns to estimate the atomic masses of unknown elements.

He found out that metals such as solids, liquids or gases were good conductors of heat.

In 1789 he authored a book on his findings ‘The Father of the Modern Science’.

More elements discovered, didn’t fit triads, so in the tables still today, so in the tables still today, they are left out until found out.

The elements of the table were organised horizontally based on their increasing atomic mass.

Question 22

How many elements were in the table?

Answer 22

80.

Question 23

Describe the structure of an atom.

Answer 23

1) The nucleus

It’s the middle of the atom

It contains protons and electrons.

It has a positive charge because of the protons.

Almost the whole mass of the body’s concentrated in the nucleus.

2) The Electrons

Electrons have virtually no mass

Move around the nucleus in atom shells.

Question 24

Explain energy changes that take place during chemical reactions.

Answer 24

Energy changes take place during chemical reactions. Exothermic reactions give out thermal energy and endothermic reactions take in thermal energy.
These changes can be measured experimentally or calculated before being analysed. Knowing the amount of energy involved in a reaction can be used to ensure that resources are used efficiently.

The amount of energy transferred can be used by calorimetry.

Question 25

Which metal could be used to displace sodium from sodium chloride in the reactivity series?

Answer 25

Potassium because its more reactive.

Question 26

Name two metals that can only be extracted by electrolysis.

Answer 26

Potassium and sodium.

Question 27

Name a metal that could be extracted from its ore using carbon.

Answer 27

Iron.

Question 28

Suggest a reason why iron is extracted using carbon rather than by electrolysis.

Answer 28

Iron is extracted using carbon rather than by electrolysis because it is found in ores and not in native state and therefore the oxygen needs to be removed.

Question 29

Suggest reason why gold is expensive, even though it is found native in rock.

Answer 29

Gold is expensive, even though it is found native in rock because its rare therefore it is hard to find (locate. There’s not lots found in the Earth’s crust.
Also people have already mined for it so there is not much left.

Question 30

What are the rules for atomic configuration?

Answer 30

Groups- how many electrons in outer shell.

Periods- how many shells the element will have.

1st- Look at periods, draw the relevant numbers of shells.
Always count up number of electrons at the end and always work out the configurations and then see if it matches the atomic numbers.

Question 31

How many electrons are in the 1st shell?

Answer 31

2 electrons.

Question 32

How many electrons are in the 2nd shell?

Answer 32

8 electrons ( check the atomic number because it could change.

Question 33

How many electrons are in the 3rd shell?

Answer 33

8 electrons.