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C2 Flashcards

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0
Q

What is the atomic number

A

The atomic number is simply the number of protons

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1
Q

What is the mass number and where would you find it

A

The mass number is the total number of protons and neutrons and it will be the first figure at the top of the symbol

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2
Q

How do I get the neutron?

A

Subtract the atomic number from the mass number

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3
Q

How are compounds formed?

A

Compounds are formed when atoms of two or more elements chemically combine together for example carbon dioxide is a compound formed from a chemical reaction between carbon and oxygen

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4
Q

What is the definition of isotopes?

A

Eiler told a different atomic forms of the same element which had the same number of protons but a different number of neutron

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5
Q

What is ionic bonding?

A

It is when atoms neutral gain electrons to form charged particles known as Ions they strongly attracted to one another because one of the opposite charges are positive and negative

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6
Q

Explain further on what I mean by ionic compounds have a regular lactase structure

A

Ionic compounds always have a giant ionic lattice the ions from a closely packed regular lattice arrangement

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

A single crystal of NaCl (sodium chloride) salt is one giant ionic lattice which is why salt crystals tend to be cuboid in shape the na+ and Cl- ions are held together in a regular lattice

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7
Q

Describe the properties of ionic compounds

A

They all have high melting points and high boiling point due to the strong attraction between the ion

When ionic compound melt the ions Are free to move and They’ll will carry out an electric current

A dissolves easily in water . The ions separate and free to move in the solution so they will carry out electric current

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8
Q

What group in the periodic table are most likely to form ions

A

Group 1 -2

Group 6&7

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9
Q

Why are group 1&2 most likely to ions?

A

Group 1 and group 2 elements are metals and they loose electrons to form positive ions

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10
Q

Why are group 6&7 most likely to form ions

A

Group 6 and seven elements are non-metals they gain electrons to form negative ions

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11
Q

What is covalent bonding?

A

It’s sharing electrons in their outer shells with other atoms to involve in having a full outer shell

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12
Q

What are the two types of covalent substances?

A

Simple molecular substances & giant covalent substances

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13
Q

What is a simple molecular substance ?

A

The atom form very strong covalent bonds to form small molecules of several atoms

by contrast the forces of attraction between these these monocles are very weak

the results of these feeble intermolecular forces is that the melting points and boiling point are very low because the molecules are easily parted from each other

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14
Q

Why don’t simple molecular substances conduct electricity ?

A

Because there are no ions so there is no electrical charge

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15
Q

What are macromolecules ?

A

These are similar to giant ionic structures (lattice) except there are no charged ions

All the atoms bonded to each other by strong covalent bonds this means that they have a very high melting and boiling point
they don’t conduct electricity not even & the main examples of Marcomolecules are diamond and graphite which are both made only from carbon atom and silicon dioxide

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16
Q

Briefly describe the properties of diamond

A

Each carbon atom forms 4 covalent bonds in a very rigid giant covalent structure this structure makes time in the hardest natural substances so it’s used for drilled tips

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17
Q

What are the properties of graphite?

A

Each carbon atom only forms 3 covalent bonds this creates layers which are free to slide over each other this is why graphite is soft and slippery there is a weaker Intermolecular forces between the Layers

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18
Q

Why is there a weak intermolecular forces between the layer of graphite

A

Each carbon atom only forms 3 covalent bonds this creates layers which are free to slide over each other the layers are held together so loosely that they could be rubbed off onto paper ;this is why pencil works

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19
Q

Why is graphite that only non-metal which is a good conductor of heat and electricity?

A

This is because each carbon atom has one free electron and it’s these free electrons that can.conduct heat and electricity

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20
Q

Describe the properties of an metal

A

They have free electrons which come from the outer shell of every metal atom in the structure electrons are free to move through the whole structure and so metals are good conductors of heat and electricity

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21
Q

Describe the structure of an metal

A

The electrons hold the atoms together in a regular structure

There are a strong forces of Electrostatic attraction between the positive metal iron and the negative electrons

The layers of atoms slide over each other allowing metals to be bent and shaped

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22
Q

Why are alloys harder than pure metals ?

A

Alloys are a mixture of 2 or more metals together

Different elements have different sized atom so when another metal is mixed with a pure metal the new metal atoms disort the layers of metal atoms making it more difficult for them to slide over each other

23
Q

What is an example of a smart material?

A

A good example is nitol (half nickel and half titanium) it is a metal alloy but when it’s cool you can bend and twisted like a rubber but if heat it above a certain temperature If goes back to its original shape

24
Q

What are nanoparticles??

A

Nano particles are really tiny particles and contain roughly 300 atoms

25
Q

What do nanoparticles include and explain what they are?

A

Nano particles include fullerenes these molecules of carbon and carbon atoms are arranged in hexagonal rings

fullerenes can be joined together for two form nano tubes . All those covalent bonds make carbon nanotubes very strong

26
Q

What are some uses of nanoparticles and how are they being developed?

A

They have a huge surface area to volume ratio so they could help make new industrial catalyst

Nanoparticles can make sensors to detect one type of molecule and nothing cast for example Pan-Pacific senses are already being used to test water purity

Cosmetic for example suntan cream and deodorant has been made using nanoparticles because the small particles do their job but don’t leave white marks on the skin

Nanotubes can be used to make stronger and lighter building materials

Nanotubes conduct electricity so they can be used in tiny electric circuit for computer chips

27
Q

What is thermosoftening polymers?

A

They don’t have cross-linking between their chains The forces between their chains are really easy to overcome so very easy to remould plastic when it cools the polymer hardens into a new shape

28
Q

What is thermosetting polymers?

A

They have a cross-link and hold the chain together in a solid structure the polymers doesn’t soften when it’s heated

29
Q

What up some properties of Thermo softening polymers?

A

Individual tangled chains of polymers held together by weak intermolecular forces are free to slide over each other

30
Q

What are some properties of thermosetting polymers?

A

Some plastics have stronger intermolecular forces between the polymer chains called “cross-linked this holds the chain family together

31
Q

What could affect the properties of a polymer ?

A

The starting material

Reaction conditions

32
Q

Describe the three factors that could reduce the percentage yield of a reaction?

A

The reaction is reversible so the reactants will never be completely converted to the product because the reaction goes both ways

Some of the products may be lost when it separated from the reaction mixture

Sometimes they can be unexpected reaction happening which uses up the reactants

33
Q

What are the advantages of using machines to analyse and unknown substances

A

They are very sensitive and detect even the tiniest amount of substances

They are very fasting tests can be automated

They are very accurate

34
Q

What is the purpose for gas chromatography?

A

It can separate out a mixture of a Compound and help you identify the substances present

35
Q

What are the main stages of gas chromatography?

A

A gas is used to carry substances for a column packed with a solid material

The substances travel through the tube at different speeds so that they are separated

The time they take to reach the detector is called the retention time it can be used to help identify the substances

The graph draws a Gas chromatograph and the number of peaks shows the number of different compounds in the sample

36
Q

Give an example of a slow reaction

A

The rusting of iron

37
Q

Give an example of a moderate speed reaction?

A

Is a metal like magnesium reacting with acid to produce a gentle steam of bubbles

38
Q

Give an example of a really fast reaction

A

An explosion where it’s all over in the fraction of a second

39
Q

What four factors: can change the rate of reaction

A

Temperature
Concentration or pressure for
Catalyst
The surface area of a solid

40
Q

What formula can be used to measure the rate of a reaction

A

Rate of reaction = amount of reactant used or amount of product formed / time

41
Q

What are the different ways rate if reaction can be measured

A

Precipitation - this is when the product of the reaction is a precipitate which clouds dissolution

Change in mass usually gas given off-measuring the speed of a reaction that produces a glass can be carried out on a mass balance as the gas is released the Mass disappearing is easily measured balanced

The volume of gas given off- this involves the use of a gas syringe to measure the volume of gas given off the more gas given off during a given time the faster the reaction

42
Q

How does having a higher temperature increase collision?

A

When the temperature is increasing the particles move quicker and if they are moving quicker they are going to collide more often

43
Q

How does having an high concentration or pressure increase collision ?

A

If a solution is made more concentrated it means there are more particles of reactant between the water molecules which make collisions between the important particles more likely.In a gas increasing the pressure means the particles are more squashed up together so there will be more frequent collisions

44
Q

How does having a larger surface area increases collision ?

A

If one of the reactants is a solid then breaking it up into smaller pieces will increase the total surface area this means the particles around it in the solution will have more areas to work on so there will be more frequent collision

45
Q

How does faster collisions increase the rate of reaction?

A

High-temperature also increases the energy of the collision because it makes all the particles move faster
Reaction only happens if the particles collide with enough energy(activation energy )
At a higher temperature or there will be more particles colliding with enough energy to make the reaction happen

46
Q

What does activation energy mean?

A

The minimum amount of energy needed by the particles to react

47
Q

What is a catalyst?

A

A catalyst is a substance which speeds up a reaction without being changed or used up in the reaction

48
Q

How does a catalysts speed up the reaction

A

A solid catalyst works by giving the reacting particles a surface to stick to this increases the number of successful collision and so speeds up the reaction

49
Q

What are some advantages of using a industrial catalyst

A

Catalyst increases the rate of reaction which saves a lot of money

Catalyst will allow a reaction to work at a much lower temperature which is good for sustainable development and save money too

A catalyst can never get used up in the reaction so it could be reused

50
Q

What are some disadvantages of using a industrial catalyst

A

They can be very expensive to buy an often needs to be removed from the product and be cleaned

Different reactions is different catalyst so if you make more than one product you will need to buy different catalysts for them

Catalysts can be poisoned by impurities so they can stop working this means you have to keep your reaction mixture of very clean

51
Q

What is an exothermic reaction?

A

Is one which transfers energy to the surrounding usually in the form of heat and usually shown by a rise in temperature

52
Q

Examples of exothermic reactions

A

Burning fuel also called combustion gives out a lot of heat
Neutralisation reaction so acid + alkali are also exothermic
Oxidation reaction are exothermic e.g. adding sodium to water produces heat

53
Q

What does endothermic reaction mean

A

Is one which takes in energy from the surrounding usually in the form of heat are usually shown by a fall in temperature

54
Q

Examples of endothermic reaction?

A

Thermal decomposition E.g. heat must be supplied to make calcium carbonate decomposed to make quick lime
Sports injury patsies endothermic reaction they take in heat and the pack becomes very cold

Science (10 decks)

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