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chemistry test Flashcards

1
Q

what are positive ions sometimes called

A

cations

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2
Q

what are negative ions sometimes called

A

anions

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3
Q

how are ions arranged in an ionic bond

A

positive and negative ions are held strongly together by electrostatic forces (of attraction), ionic compounds are arranged in lattices

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4
Q

do ionic substances have high or low melting and boiling points?

A

high

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5
Q

ionic substances are generally soluble in water, true or false?

A

true

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6
Q

ionic substances ? conduct electricity in a solid form because the ions are held in position and are ? free to ?

A

cannot, not, move

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7
Q

ionic substances ? conduct electricity in a ? or molten form because the ? are free to ?

A

can, liquid, ions, move

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8
Q

when can ionic substances also conduct electricity?

A

when they’re dissolved in water

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9
Q

what are covalent bonds?

A

they are bonds which are form between 2 or more non metal elements.

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10
Q

what do elements in covalent bonds want to do

A

gain electrons to gain a full outer shell

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11
Q

what are the two types of covalent substances

A

simple covalent and giant covalent

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12
Q

what are simple covalent substances composed of

A

tiny separate molecules called molecules

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13
Q

what do simple covalents consist of?

A

several atoms bonded strongly together by covalent bonds

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14
Q

giant covalents : contain? of atoms bonded by many ? covalent bonds to form a giant ? or ? molecule

A

millions, strong, molecule, macro

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15
Q

what are noble gases and are they reactive or unreactive?

A

they are the gases in the 0/8th group of the periodic table, so they have a full outer shell of electrons and are therefore incredibly unreactive.

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16
Q

what are forces between neighbouring molecules in covalent substances called

A

intermolecular forces

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17
Q

are the intermolecular forces in simple covalents weak or strong?

A

weak

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18
Q

do simple covalent substances have high or low melting and boiling points?

A

low

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19
Q

why is electrical conductivity poor in simple covalent substances?

A

because there are no ions or free electrons present since it is a covalent substance not an ionic one!!

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20
Q

simple covalent substances are ? in water due to no charged ? present to be ? to polar water molecules

A

insoluble, particles, attracted

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21
Q

what element is in both diamond and graphite?

A

carbon!!

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22
Q

diamond structure :

A

each carbon atom joins to 4 others, and there are strong covalent bonds throughout the whole substance!

23
Q

Graphite structure :

A

Each carbon atom is covalently bonded to 3 others, has a layered structure, strong covalent bonds through layers, but weak intermolecular forces between layers

24
Q

Does diamond have a high or low melting point and why

A

Very high, because of a vast amount of strong covalent bonds having to be broken

25
Q

Diamond is very ? due to very strong ? bonds throughout the structure, and because of this structure, it has ? electrical conductivity as there are no delocalised ?

A

Hard, covalent, poor, electrons

26
Q

What is diamond used in and why?

A

Drill bits for hardness and jewellery for shininess

27
Q

Why does graphite have a high melting point?

A

Because the strong covalent bonds between the layers have to be broken

28
Q

Graphite is soft, due to ? intermolecular forces ? layers, therefore layers can easily ?. Graphite is a ? electrical conductor, because it has ? electrons between the carbon ?

A

weak, between, slide, good, delocalised, layers

29
Q

What is graphite used for?

A

Pencil ‘lead’

30
Q

What does graphite do in pencil ‘lead’?

A

Lubrication can take place, the layers Slide Over each other (also used as electrodes due to good electrical conductors)

31
Q

What are atoms in metals held together by

A

Metallic bonds

32
Q

In a metallic structure what do the positive metal ions consist of

A

The contents of the nucleus and inner shell electrons

33
Q

In a metallic structure positive metal ions are held together by the ? shell of ? which become ?

A

outer, electrons, delocalised

34
Q

Why do metallic structures have high melting and boiling points?

A

Because lots of energy is needed to break the attractive forces between the delocalised electrons and positive ions

35
Q

Why are metals malleable and ductile

A

Because the metal layers can Slide Over each other when a force is applied

36
Q

Metals are good conductors of electricity- why?

A

The electrons in the sea of delocalised electrons are also free to move, so can flow when a voltage is applied

37
Q

Why are metals good conductors of heat?

A

Since when heated the delocalised electrons gain kinetic energy, and so move faster through the material therefore transferring (more) heat

38
Q

How are alloys different from metals

A

Alloys have more than one type of metal and so the different metal atoms prevent the layers from sliding over one another so the alloys are a lot harder and less malleable

39
Q

Why aren’t alloys regarded as compounds?

A

Because there isn’t any permanent chemical change, so can separate the metals by physical means if you really want to

40
Q

Meaning of ductile

A

Able to be drawn out into a thin wire

41
Q

What type of structure does a metal have?

A

A lattice structure

42
Q

What is graphene

A

A single layer of graphite, one atom thick

43
Q

Graphene is an ? electrical conductor (at RTP) and has very ? electrical resistance

A

excellent, low

44
Q

What can graphene be used to make?

A

Super fast electrical components and computer processors as well as strong and lightweight construction materials

45
Q

What are fullerenes

A

3D hollow shapes of carbon, with 60 carbon atoms, they are simple molecular substances

46
Q

Fullerenes have ? intermolecular forces ? the C60 molecules, meaning that fullerenes have a ? boiling point as only ? forces have to be overcome, so no covalent bonds are ?

A

weak, between, low, weak, broken

47
Q

What can fullerenes be used for?

A

To deliver drugs, act as lubricants and as catalysts

48
Q

What are carbon nanotubes?

A

Cylindrical fullerenes

49
Q

Carbon nanotubes are :
Exceptionally ? and very good ? of heat and electricity. can be used as semi conductors in ? circuits, ? and for reinforcing materials eg : ? rackets

A

strong, conductors, electrical, catalysts, tennis

50
Q

Why are catalysts often (attached to) carbon nanotubes?

A

Because nanotubes have a large surface area and with a larger surface area the reactants will collide more with the catalyst

51
Q

What are polymers

A

Long chain like molecules

52
Q

The atoms in the ? chain are linked to each other by ? covalent bonds so the ? forces are strong

A

Polymer, strong, intramolecular

53
Q

In some polymers the forces between chains are relatively weak, how does this affect these chains?

A

The polymers have a low melting point and so are flexible as the chains can move over each other, and have weak intermolecular forces - these polymers can be used for flexible materials eg : plastic bags

Chemistryyy (40 decks)

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