Chemistry C4 Ocr Gateway B

Front 1

Give 4 facts about the nucleus of an atom
(Charge, location, size, mass, contains)

Back 1

- Positive
- In the middle of the atom
- Contains protons and neutons
- Almost the whole mass of the atom is concentrated in the nucleus

Front 2

Give 4 facts about electrons
(Charge, location, size, mass)

Back 2

- Negatively charged
- Move around the nucleus in electron shells
- They're very small, but cover a lot of space
- Have virtually no mass

Front 3

What are the charges and masses of the following?
a) Protons
b) Neutrons
c) Electrons

Back 3

Protons: Charge = +1 Mass = 1
Neutons: Charge = 0 Mass = 1
Electrons: Charge = -1 Mass = 0.0005

Front 4

Why do neutral atoms have no charge overall?

Back 4

Because they have the same number of protons as electrons
(the charge on the electrons is the same size as the charge on the protons but opposite so they cancel out)

Front 5

What is the top number of an atom?
Eg 23
Na
11

Back 5

The mass number

Front 6

What does the mass number tell us?

Back 6

The number of protons and neutrons

Front 7

What is the bottom number of an atom?
Eg 23
Na
11

Back 7

The atomic number

Front 8

What does the atomic number tell us?

Back 8

The number of protons

Front 9

What are the verticle columns of the periodic table called?

Back 9

Groups

Front 10

What does the group of an element correspond to?

Back 10

The number of electrons it has in its outer shell

Front 11

What are the rows of the periodic table called?

Back 11

Periods

Front 12

What does the period to which the element belongs to correspond to?

Back 12

The number of shells of electrons it has

Front 13

What are isotopes?

Back 13

Isotopes are different forms of the same element, which have the same number of protons but a different number of neutrons
Eg. Carbon 12 (6p,6e, 6n) and Carbon 14 (6p, 6e, 8n)

Front 14

What happens in ionic bonding?

Back 14

Atoms lose or gain electrons to form charge particles (ions) which are then strongly attracted to each other

Front 15

What does ionic bonding occur between?

Back 15

A metal and a non-metal

Front 16

Explain the structure ionic compounds form

Back 16

Produce giant ionic structures = the ions form a closely packed regular lattice arrangement. The ions are not free to move and so do not conduct electricity. There are very strong chemical bonds between the ions

Front 17

Give two examples of giant ionic structures

Back 17

1. MgO = Magnesium Oxide
2. NaCl = Sodium Chloride

Front 18

Why do magnesium oxide and sodium chloride have high melting and boiling points?

Back 18

They have a very stong attraction between the oppositely charged ions in the structures and so to break the bonds you need lots of energy to overcome the forces of attraction

Front 19

Why does magnesium oxide have a higher melting point than sodium chloride?

Back 19

- It's made of Mg(2+) and O(2-) ions which have double the charge of Na(+) and Cl(-) ions so the attraction is harder to overcome.
- Also O(2-) ions are smaller than Cl(-) ions so the ions in MgO can pack together more closely = attraction harder to overcome

Front 20

What happens when metals form ions?

Back 20

They lose electrons to form positive ions

Front 21

What happens when non-mentals form ions?

Back 21

They gain electrons to form negative ions

Front 22

How do you work out the charge on the ion?

Back 22

It is the same as the number of electrons lost or gained
Eg. If two electrons are gained then the charge is -2
Eg. If three electrons are lost, the charge is +3

Front 23

What is covalent bonding between?

Back 23

Two non-metal atoms combine by sharing pairs of electrons

Front 24

Why are the melting points and boiling points of simple molecular structures formed from covalent bonds usually very low?

Back 24

Because the forces between the molecules are very week and are easily parted from each other

Front 25

Why don't molecular substances conduct electricity?

Back 25

Don't have free electrons or ions

Front 26

What metals are in group 1?

Back 26

Lithium, sodium, Potassium, Rubidium, Caesium and Francium

Front 27

What happens to the reactivity as you go down the alkali metals?

Back 27

Reactivity increases because the outer electron is more easily lost because it's further from the nucleus so less energy is needed to remove it

Front 28

Why are the alkali metals very reactive?

Back 28

They all have one outer electron

Front 29

What 3 physical properties do the alkali metals share?

Back 29

1. Low melting points and boiling point
2. Low density
3. Very soft

Front 30

Will the alkali metals form covalent or ionic compounds?

Back 30

They are keen to lose the oiter electrons to form a 1+ ion with a stable electronic structure

Front 31

What is oxidation?

Back 31

The loss of electrions

Front 32

Explain what happens when lithium, sodium or potassium are put in water

Back 32

React vigorously: move around the surface, fizz, produce hydrogen
Potassium = hot enough to ignite it
Sodium and potassium = melt in the heat

Front 33

What forms when lithium, sodium or potassium are put in water? Give a balanced symbol equation

Back 33

An alkali forms which is the hydroxide of the metal

2Na + 2H(2)O = 2NaOH + H(2)
Sodium + Water = Sodium hydroxide + Hydrogen

Front 34

How do you do a flame test to identify the alkali metal that is present?

Back 34

1. Dip wire loop into hydrochloric acid to clean and moisten
2. Put the loop into powdered compound and place in blue bunsen flame

Front 35

What colours will be produced in a flame test from:
a) Lithium?
b) Sodium?
c) Potassium?

Back 35

a) Red
b) Yellow/orange
c) Lilac

Front 36

What elements are in group 7 (Halogens?

Back 36

Fluorine, chlorine, bromine, iodine, astatine

Front 37

What happens to the reactivity as you go down group 7?

Back 37

It decreases because there's less inclination to gain the extra electron to fill the outer shell when it is further away from the nucleus

Front 38

What happens to the melting and boiling points of the halogens as you go down the group?

Back 38

They increase

Front 39

What are the properties of these elements at room temperature
a) Chlorine?
b) Bromine?
c) Iodine?

Back 39

a) A dense green, poisonous gas, fairly reactive
b) A dense, poisonous orange liquid
c) A grey crystalline solid

Front 40

Why are the halogens keen to gain an electron?

Back 40

To form a 1- ion with a stable electronic structure

Front 41

What is reduction?

Back 41

The gain of electrons

Front 42

What do the Halogens and the alkali metals react together to form?

Back 42

Salts called 'metal halides'

Front 43

Why do all metals have the same basic properties?

Back 43

Metals are held together by metallic bonds that allow the outer electron(s) of each atom to move freely. This creates a sea of delocalised electrons which gives the properties.

Front 44

What properties do all metals have? (6 points)

Back 44

1. Hard, dense and lustrous
2. High melting/boiling points because of strong metallic bonds
3. Strong attraction between the delocalised electrons and the closely packed positive ions (strong metallic bonding)
4. The strength of the metallic bond decreases as the atomic radius increases
5. Malleable
6. Good conductors of heat

Front 45

What metal is used to make saucepans? What are its properties?

Back 45

Stainless steel
- Good conductor of heat
- Doesn't rust easily

Front 46

What metal is used to make electrical wiring. What are it's properties?

Back 46

Copper
- Good conductor of electricity
- Easily bent

Front 47

What metal is used to make planes? What are it's properties?

Back 47

Aluminium
- Low density (light)
- Strong
- Doesn't corrode

Front 48

What metal is used to make bridges? What are it's properties?

Back 48

Steel
- Strong

Front 49

What happens if you make some metals very cold?

Back 49

Their resistance disappears and becomes a superconductor

Front 50

Why do you want the resistance of the metal to disappear?

Back 50

None of the electrical energy is turned into heat so none of it's wasted

Front 51

What 3 things can be made with superconducting wires?

Back 51

1) Power cables that transmit electricity without any loss of power
2) Strong electromagnets that don't need a constant power source
3) Electronic circuits that work very fast

Front 52

How cold do metals have to be made before they become a superconductor?

Back 52

-265 degrees celcius

Front 53

What are the 2 disadvantages of superconducting metals?

Back 53

- Expensive to get to the low temperature
- Very hard to reach the temperature

Front 54

What are the metals in the middle of the periodic table called?

Back 54

Transition metals

Front 55

Give a use of
a) Iron
b) Nickel

Back 55

a) Catalyst in the haber process
b) Useful for the hydrogenation of alkenes

Front 56

What compounds do
a) Iron (III) make?
b) Iron (II) make?
c) Copper make?

Back 56

a) Orange/brown
b) Light green
c) Blue

Front 57

What do transition metal carbonates break down into when heated?

Back 57

A metal oxide and carbon dioxide
Resulting in a colour change

Front 58

How can you check if the gas given off is carbon dioxed?

Back 58

By bubbling it through limewater and if CO(2) is present it turns milky

Front 59

What is a precipitation reaction?

Back 59

Where two solutions react and an insoluble solid forms in the solution

Front 60

Give the word and symbol equation for the reaction between copper (II) sulfate and sodium hydroxide

Back 60

CuSO(4) + 2NaOH = Cu(OH)(2) + Na(2)SO(4)

Copper(II) sulfate + sodium hydroxide = copper(II) hydroxide + Sodium sulfate

Front 61

How can you test for transition metal ions?

Back 61

Using precipitation because some insoluble transition metals have distinctive colours

Front 62

What 3 uses does water have in industry?

Back 62

A cheap raw material, a coolant and a solvent

Front 63

What two sources do we get our water from in the UK?

Back 63

a) Surface water eg. lakes, rivers and reservoirs
b) Groundwater eg. aquifers (rocks that trap water underground)

Front 64

Why are groundwater and surface water limited?

Back 64

They depend on annual rainful

Front 65

How is water from surface water sources purified? (3 points)

Back 65

1. Filtration
2. Sedimentation
3. Chlorination

Front 66

Explain filtration

Back 66

A wire mesh screens out large twigs etc
Sand and gravel beds filter out any other solid bits

Front 67

Explain sedimentation

Back 67

Iron sulfate or ammonium sulfate is added to the water making fine particles clump together and settle at the bottom

Front 68

Explain chlorination

Back 68

Chlorine is bubbled through to kill harmful bacteria and microbes

Front 69

What impurites can tap water still contain? What consequences do they have?

Back 69

1) Nitrate residues from excess fertiliser. Prevent the blood carrying oxygen properly. Serious health problems, especially for children
2) Lead compounds from old lead pipes. Very poisonous, especially for children
3) Pesticide residues from spraying near to rivers/lakes

Front 70

What is another option to get fresh water?

Back 70

Distilling sea water

Front 71

What are two disadvantages of distilling sea water?

Back 71

Needs a lot of energy and is therefore expensive.
It is not practical for producing large quantities of fresh water

Front 72

How can you test for dissolved ions in water?

Back 72

Using precipitation reactions

Front 73

What is the test for sulfate ions?

Back 73

1) Add dilute hydrochloric acid to test sample
2) Add 10 drops of barium chloride solution
3) White precipitate = sulfate ions

Front 74

Give the symbol and word equation for sulfate ions and barium ions

Back 74

Barium ions + sulfate ions = Barium sulfate
Ba (2+) + SO(4) (2-) = BaSO(4)

Front 75

What is the test for halide ions?

Back 75

1. Add dilute nitric acid to the test sample
2. Add 10 drops of silver nitrate solution
3. Chloride ions present = white precipitate
Bromide ions present = cream precipitate
Iodide ions present = pale yellow precipitate

Front 76

Give the word and symbol equation for silver nitrate and sodium chloride

Back 76

Silver nitrate + sodium chloride = silver chloride + sodium nitrate

AgNO(3) + NaCl = AgCl + NaNO(3)