Chemisty || Basics C1 - C12

Question 1

Hazard Symbol: Oxidising?

Answer 1

Circle with fire on top.

Question 2

Hazard Symbol: Harmful?

Answer 2

Punctuation point.

Question 3

Hazard Symbol: Environment Hazard?

Answer 3

Tree and fish.

Question 4

Hazard Symbol: Toxic?

Answer 4

Skull.

Question 5

Hazard Symbol: Highly Flammable?

Answer 5

Fire.

Question 6

Hazard Symbol: Corrosive?

Answer 6

Broken test tube and hand.

Question 7

What Changes Did Mandeleev Make To The Periodic Table?

Answer 7

Sorted them into elements based on their properties,

Put them in order of atomic mass,

Predicted elements not yet found.

Question 8

Oxidation?

Answer 8

Gain of oxygen,

On left of arrow.

Question 9

Reduction?

Answer 9

Loss of oxygen,

On right of arrow.

Question 10

Ionic Compounds Are?

Answer 10

Ions with a giant ionic lattice stucture.

Question 11

Ionic Compound Properties?

Answer 11

High melting and boiling points due to strong attraction,

Don’t contact electricity,

Will conduct electricity when they are dissolved or molten.

Question 12

Covalent Bond?

Answer 12

A pair of electrons is shared between two atoms,

Only have 1 electron each and they share that 1 electron with another element with 1 electron.

Question 13

Covalent Bond Properties?

Answer 13

Have simple molecular structures,

Weak attraction,

Don’t conduct electricity unless dissolved but some cannot dissolve,

They are gases or liquids at room temperature,

Melting points are low because easily separate from each other.

Question 14

Giant Covalent Structure Properties?

Answer 14

All atoms are bonded together with strong bonds,

High melting points and boiling points,

Don’t conduct electricity because they don’t have charged particles,

Aren’t soluble in water.

Question 15

Giant Covalent Structure?

Answer 15

All atoms are bonded together by strong bonds,

All atoms touch/bond together.

Question 16

Finding Relative Formula Mass Of Two Ions?

Answer 16

Using abundance,

Times the ion by the percentage,

Times the other ion by their percentage,

Add together,

Dived by 100 because it was out of 100%,

Answer.

Question 17

Relative Formula Mass?

Answer 17

Finding the atomic number of all the atoms and adding them together,

This is Mr.

Question 18

Pure Substances Melting Points?

Answer 18

They are sharp,

Suddenly go from a solid to a liquid.

Question 19

Mixed Substance Melting Points?

Answer 19

They are gradual,

Gradually melt from a solid to a liquid.

Question 20

Simple Distillation?

Answer 20

Separating a liquid from a solution,

Involves heating a test tube and condensing the evaporated solution.

Question 21

Fractional Distillation?

Answer 21

This is used to separate a mixture (mixed liquid),

Start by heating the test tube gradually and each solution will leave at different temperatures,

Liquids with higher boiling points will come last and liquids with lower will come out first.

Question 22

Filtration?

Answer 22

Used to separate a insoluble solid from a liquid.

Question 23

Crystallisation?

Answer 23

Separates a soluble solid from a solution (liquid),

Pour solution into evaporating dish,

Heat the dish,

Water will evaporate so the solution left will be more concentrated,

Remove dish when crystals form,

It is insoluble in the cold air so crystals start to form,

Filter the crystals out from the solution.

Question 24

How Do We Make Water Drinkable?

Answer 24

Filtration,

Sedimentation,
Iron or aluminium sulphate used to make fine particles clump together and settle at bottom of water,

Chlorination,
Chlorine gas is bubbles through to Kidd bacteria and microbes.

Question 25

Ph Scale?

Answer 25

0-6 (Acidis),

7 (Neutral),

8-14 (Alkalis).

Question 26

Necessaries For Making A Salt?

Answer 26

Reacting acid with a insoluble reactant such as:

• A metal,
• A metal oxide,
• A carbonate,

The reactant depends on what salt you are making,

For example: copper doesnt react with dilute acids so copper salts can’t be made this way,

Sodium is too reactive to be used safely to make salts.

Question 27

Why Use Metal Oxide Instead Of Pure Metals While Making Salts?

Answer 27

Because the pure metals are flammable whilst carbonates are not.

Question 28

Salt Names?

Answer 28

First part comes from metal, second part comes from acid,

E.g. Copper + Hydrochloric Acid = Copper Chloride.

Question 29

How Do You Make A Insoluble Salt?

Answer 29

Process called Precipitation Reaction,

You pick two soluble salts and react them together to get an insoluble salt.

Question 30

How To Make A Soluble Salt?

Answer 30

React an acid that contains an ion you want the salt to have and a insoluble base you want the salt to have,

E.g. copper oxide + sulphuric acid = copper sulphate,

Start by heating the acid in a water bath (this speeds the reaction up),

Do this in a fume cupboard to avoid releasing acid fumes,

Then add the base,

There should be some of the base leftover (this means it is in excess of base which is good because it means there’s not excess acid),

Filter the excess solid to get a solution containing only the salt and water,

Heat the solution to evaporate water,

Allow salt to crystallise.

Question 31

Soluble Salts?

Answer 31

Sodium,

Potassium,

Ammonium,

Nitrates,

Chlorides (minus silver and lead chloride),

Sulfates (minus lead, barium and calcium).

Question 32

Insoluble Salts?

Answer 32

Common carbonates and hydroxides,

(Minus sodium, potassium and ammonium).

Question 33

Ending In “IDE”

Answer 33

Negative ions containing only one element.

Question 34

Ending in “ATE”?

Answer 34

Negative ions containing oxygen and at least one other element.

Question 35

Molecules To Memorise?

Answer 35

Water - H20,

Ammonia - NH3,

Carbon Dioxide - CO2,

Hydrogen - H2,

Chlorine - Cl2,

Oxygen - O2.

Question 36

Ions To Memorise?

Answer 36

Ammonium - NH4+,

Hydroxide - OH-,

Nitrate - NO3,

Carbonate - CO3 2-,

Sulfate - SO4 2-.

Question 37

How To Write An Ionic Equation?

Answer 37

Balance the formula given first,

Break up the formula,

Anything that is aqueous will break up but anything liquid or solid will stay contact,

Do swap and drop method to get the correct charges on the ions when you split them up,

Cross out any duplicates (only if they’re on both sides),

Should be left with a new formula and charges should be equal on both sides.

Question 38

Ionic Compounds Structure?

Answer 38

Have a giant ionic lattice Structure,

The ions form a closely packed regular lattice,

There are very strong electrostatic forces of attraction between oppositely charged ions in all directions,

The structure looks like a solid cube made of 5 by 5 spheres.

Question 39

Ionic Compound Properties?

Answer 39

High melting and boiling pints due to stein attraction between the ions,

Takes a large amount of energy to break the bond,

Solid ionic compounds cannot conduct electricity because the jobs are fixed and can’t move,

The ionic compound will conduct electricity when the solid is melted or dissolved because the ions are free to love and carry the current.

Question 40

How Do Models Show Structures?

Answer 40

It’s hard to draw out exactly what a substance looks like so we use models,

We use:

• 2D Representations,
• Dot And Cross Diagrams,
• 3D Models.

Question 41

2D Representations Positives And Negatives?

Answer 41

E.g. displayed formulas of molecules,

Simple and great at showing what atoms something contains and how the atoms are connected,

However, they don’t show the shape of the substance and they don’t give you any idea about the size of the atoms.

Question 42

Dot And Cross Diagrams Positives And Negatives?

Answer 42

Useful for showing how compounds or molecules are formed and where the electrons in the bonds or ions come from,

However, they don’t show you anything about the size of the atoms or how they are arranged.

Question 43

3D Models Positives And Negatives?

Answer 43

Show arrangement of ions,

However, only show the outer layer of the substance,

Ball and stick models show how the atoms in a substance are connected. You can draw them or make them with plastic molecular model kits (the balls and sticks we use in class),

They help visualise structures and show shape of lattice in 3D,

They’re more realistic then drawings but they’re still misleading as they make it look like there a big gaps between the atoms,

They also don’t show the correct scale of atoms or ions.

Question 44

Polymers?

Answer 44

Made of long chains of covalently bonded carbon atoms,

They’re formed when lots of small molecules called monomers join together,

This can be shown like this:

(  H   H    )
(   |    |     ) 
(- C - C -)
(   |     |    )
(  H    H   )n     

The “n” shows that there are lots of these units joined together, showing a polymer.

Question 45

Simple Molecular Substance Properties?

Answer 45

Substances with covalent bonds usually have simple molecular structures,

The atoms within the molecules are held with covalent bonds,

Very weak intermolecular forces,

Low melting and boiling points because bonds are weak,

Most are gases or liquids at room temperatures,

As molecules get bigger, the strength of the forces increased and more energy is needed to break them so boiling and melting points increase,

Don’t conduct electricity because they have no free electrons,

Some are soluble in water and some aren’t.

Question 46

Diamond?

Answer 46

A giant covalent structure made of carbon atoms (for example) that has 4 covalent bonds,

Strong bonds,

Take a lot of energy to break them so high melting point,

Hold atoms in a rigid lattice structure, making the diamond really hard,

Doesn’t conduct electricity because carbon forms 4 covalent bonds so there’s no free electrons.

Question 47

Graphite?

Answer 47

Each carbon atom form three bonds,

Created sheets of carbon atoms, arranged in hexagons,

There aren’t any covalent bonds between the layers, they’re held together weekly so they’re free to move over each other,

This means graphite is sold and slippery,

Lubricating material,

High melting point because they bonds in the layers are strong,

Three of carbons four bonds are used so there are extra electrons so graphite can conduct electricity.

Question 48

What Is The Name For A Free Electron (Like In Graphite)?

Answer 48

The electron is delocalised,

This means it is free and can move.

Question 49

Graphene?

Answer 49

A type of fullerene is one layer of graphite,

It’s a sheet of carbon atoms, joined as hexagons,

The sheet is just one atom thick, making it a two-dimensional compound.

Question 50

Fullerenes?

Answer 50

Are molecules of carbon, shaped like closed tubes or hallow balls,

They’re mainly made up of carbon atoms are arranged in hexagons but can also contain pentagons (rings of five carbons) or heptagons (rings of seven carbons),

They can be used to cage other molecules,

The structure forms around another atom or molecule which is then trapped inside,

This could be used to deliver a drug directly to cells in the body,

Fullerenes have a huge surface area so they could help make great industrial catalysts.

Question 51

Example Of A Fullerene?

Answer 51

Buckminsterfullerene,

C60,

Is a hollow sphere,

Made of 20 hexagons and 12 pentagons,

It is a stable molecule hat firms a soft, brownish crystal.

Question 52

Nanotubes?

Answer 52

Also fullerenes,

They are like tiny cylinders of grapheme,

Conduct electricity,

They also have a high tensile strength - this means they don’t break when they are stretched,

This means they can be used to strengthen materials without adding much weight,

For example, they can be used to strengthen sports equipment that needs to be strong but also light weight, e.g. a tennis racket.

Question 53

Metallic Bonding?

Answer 53

Metals also consist of a giant structure,

The electrons in the outer shell of the metal atoms are delocalised,

There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons,

These forces of attraction hold the atoms together in a regular structure and are known as metallic bonding.