C2 Chem Flashcards

1
Q

Giant covalent structure

A

All atoms are covalently bonded in a massive network such as diamond
Are sometimes called macro molecular substances

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2
Q

Giant covalent structure has a high or low melting point?

A

High

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3
Q

Diamond properties

A
  • Carbon atom is joined to four other covalent bonds
  • Has high melting point because a lot of covalent bonds has to be broken
  • is very hard because atoms are bonded in a rigid network
  • it is an insulator because there are no free electrons to move around
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4
Q

Properties of graphite

A
  • carbon atom is joined to three covalent bonds that forms layers
  • very high melting point because a lot of covalent bonds have to be broke
  • soft and slippery because the layers can slide over each other
  • conductor because it has delocalized electrons
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5
Q

What are fullerenes?

How many carbon does it contain?

A

Are molecules made up of linked carbon rings

It contains 60 carbon atoms in a spherical shape

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6
Q

Simple molecular substance

A
  • There are millions of separate but identical molecules such as water
    Low melting and boiling points because it has weak intermolecular forces
  • Non conductive because the electrons are not free to move
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7
Q

What is an alloy?

A

A mixture of a metal with small amounts of other metals or carbon

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8
Q

Why can metals be bent and hammered into shape?

A

Because the layers of metal atoms can slide over each other easily whilst maintaining the metallic bonding

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9
Q

Why are alloys harder than pure metal?

A

Because different metal atoms in alloys jam up the metal structure that stops the layers of atoms from sliding past each other easily

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10
Q

What is a shape memory alloy?

Example?

A

An alloy that can return to its original shape after being deformed
Nitinol

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11
Q

What are the uses of a shape memory alloy such as nitinol?

A

Wires in dental braces

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12
Q

Structure of thermo softening polymers

A
  • Long polymer chains are not joined up

- they soften and melt when heated because they have weak intermolecular forces

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13
Q

Stricture of thermosetting polymers

A
  • polymer chains are joined to each other by strong covalent bonds that makes them not soften or melt
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14
Q

What are atoms?

A

A particle with no overall charge

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15
Q

What is an element?

A

Element is a substance made up of only 1 atom

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16
Q

What is a compound?

A

A substance made up of more than type of atom that are chemically joined together

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17
Q

How are compounds broken down?

A

By thermal decomposition or electrolysis

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18
Q

Rules for covalent bonding

A
  • A pair of electrons are shared between 2 atoms

- between nonmetals only

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19
Q

Rules for ionic bonding

A
  • electrons are transferred between 2 atoms

- occurs between metal and non metal

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20
Q

What is nanoScience?

A

The study of nanoparticles

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21
Q

Why are nanoparticles have different properties?

A

They have a much larger surface area to volume ratio

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22
Q

What are the uses of nanoparticles?

A

They can be used as sensors for example, to detect toxic lead ions
They can be used in clothes to kill bacteria and prevent smells

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23
Q

What are the concerns of nanoparticles?

A
  • since they have different properties, they may be toxic

- they might be more reactive than bulk material

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24
Q

Definition of a nanoparticle?

A

A particle between 1 - 100 nanometer in size

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25
Q

How are the ions arranged in an ionic lattice?

A

Ions are packed in an ordered,regular structure

26
Q

What is the percentage yield?

A

The amount that is actually produced with the amount expected in theory

27
Q

How to calculate percentage yield?

A

Mass of product obtained/maximum theoretical mass of product * 100

28
Q

What is an empirical formula?

Examples

A

The ratio of atoms or ions in a substance
Butane C4H10 = C2H5
Octane C8H18 = C4H9

29
Q

How do you make insoluble salts?

A

Reacting together solutions of two soluble salts

30
Q

What is a precipitate in terms of salts?

A

An insoluble solid (salt) formed when reacting two soluble salts together

31
Q

What are the main soluble salts?

A

All Sodium, potassium, ammonium (carbonates and hydroxides)
All nitrates
Most chlorides, bromides and iodides
Most sulfates

32
Q

What are the main Insoluble salts?

A

Barium,calcium and leaf sulfate
Most carbonates and hydroxides
Lead and silver chloride, bromide and iodide

33
Q

How to make soluble salt?

A

Reacting metal with acid

34
Q

What is a base?

A

A compound, usually metal oxide or hydroxide that reacts with acid to neutralize it

35
Q

Examples of soluble salts?

A

Sodium nitrate

Sodium chloride

36
Q

Examples of insoluble salts?

A

Lead sulfates

Lead chloride

37
Q

What kind of ions do alkalis release when they are dissolved in water?

A

Hydroxide ions (OH-)

38
Q

What kind of ions do acids release when dissolved in water?

A

Hydrogen ions (H+)

39
Q

What is the neutralization reaction?

A

Acids and alkalis react together to produce a salt and water
H+ + OH- = H2O

40
Q

Example of ionic equation for neutralization?

A

H+ + OH- = H20

Aqueous + Aqueous = Liquid

41
Q

What is paper chromatography?

A

A technique that separates different dyes or pigments in a colored substance using paper

42
Q

What is gas chromatography?

A

A method that separates chemicals in a small sample using un-reactive gases

43
Q

What is mass spectroscopy?

A

An analytical technique that involves breaking molecules into charged fragments and measuring their mass ratio

44
Q

What are key factors that affects the rate of reaction?

A

Temperature
Surface area
Concentration
The use of a catalyst

45
Q

What is the retention time?

A

Time taken for substance to detector at the end of the column

46
Q

What is the minimum energy required for reactions to start?

A

Th activation energy

47
Q

What are catalysts?

A

A chemical compound that speeds up chemical reactions without being used up

48
Q

Pros and cons of catalysts?

A

Are are used to speed chemical reactions up without being used up

However, some catalysts are expensive since such as the platinum used in fuel cells

49
Q

What is an exothermic reaction?

Example?

A

Chemical reaction that give out energy (heat)
Make bonds
Metal + acid = salt + hydrogen

50
Q

What is an endothermic reaction?

Example?

A

Reactions that take in energy
Break bonds
Photosynthesis

51
Q

Examples of reversible reactions?

A

Hydrated copper sulfate = anhydrous copper sulfate + water
Blue White

Endothermic and exothermic

52
Q

Example of reversible reaction?

A

Photosynthesis and respiration

53
Q

What is a precipitate?

A

Insoluble Solid formed when 2 soluble salts react together

54
Q

What is electrolysis?

A

Breaking down a compound using electricity

55
Q

What is reduction?

A

Gaining electrons

56
Q

What is oxidation?

A

Loss of electrons

57
Q

Where does reduction happen in electrolysis?

A

On the negative electrode

58
Q

Where does oxidation happen in electrolysis?

A

In the positive electrode

59
Q

Examples of exothermic reactions?

A

Oxidation
Neutralization
Displacement
Combustion

60
Q

Examples of endothermic reactions?

A

Respiration

Photosynthesis

61
Q

Acid plus metal

A

Salt and hydrogen

62
Q

Acid plus metal oxides

A

Salt plus water