chemistry test

Question 1

what are positive ions sometimes called

Answer 1

cations

Question 2

what are negative ions sometimes called

Answer 2

anions

Question 3

how are ions arranged in an ionic bond

Answer 3

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

Question 4

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

Answer 4

high

Question 5

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

Answer 5

true

Question 6

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

Answer 6

cannot, not, move

Question 7

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

Answer 7

can, liquid, ions, move

Question 8

when can ionic substances also conduct electricity?

Answer 8

when they’re dissolved in water

Question 9

what are covalent bonds?

Answer 9

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

Question 10

what do elements in covalent bonds want to do

Answer 10

gain electrons to gain a full outer shell

Question 11

what are the two types of covalent substances

Answer 11

simple covalent and giant covalent

Question 12

what are simple covalent substances composed of

Answer 12

tiny separate molecules called molecules

Question 13

what do simple covalents consist of?

Answer 13

several atoms bonded strongly together by covalent bonds

Question 14

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

Answer 14

millions, strong, molecule, macro

Question 15

what are noble gases and are they reactive or unreactive?

Answer 15

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.

Question 16

what are forces between neighbouring molecules in covalent substances called

Answer 16

intermolecular forces

Question 17

are the intermolecular forces in simple covalents weak or strong?

Answer 17

weak

Question 18

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

Answer 18

low

Question 19

why is electrical conductivity poor in simple covalent substances?

Answer 19

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

Question 20

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

Answer 20

insoluble, particles, attracted

Question 21

what element is in both diamond and graphite?

Answer 21

carbon!!

Question 22

diamond structure :

Answer 22

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

Question 23

Graphite structure :

Answer 23

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

Question 24

Does diamond have a high or low melting point and why

Answer 24

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

Question 25

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 ?

Answer 25

Hard, covalent, poor, electrons

Question 26

What is diamond used in and why?

Answer 26

Drill bits for hardness and jewellery for shininess

Question 27

Why does graphite have a high melting point?

Answer 27

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

Question 28

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

Answer 28

weak, between, slide, good, delocalised, layers

Question 29

What is graphite used for?

Answer 29

Pencil ‘lead’

Question 30

What does graphite do in pencil ‘lead’?

Answer 30

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

Question 31

What are atoms in metals held together by

Answer 31

Metallic bonds

Question 32

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

Answer 32

The contents of the nucleus and inner shell electrons

Question 33

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

Answer 33

outer, electrons, delocalised

Question 34

Why do metallic structures have high melting and boiling points?

Answer 34

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

Question 35

Why are metals malleable and ductile

Answer 35

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

Question 36

Metals are good conductors of electricity- why?

Answer 36

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

Question 37

Why are metals good conductors of heat?

Answer 37

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

Question 38

How are alloys different from metals

Answer 38

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

Question 39

Why aren’t alloys regarded as compounds?

Answer 39

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

Question 40

Meaning of ductile

Answer 40

Able to be drawn out into a thin wire

Question 41

What type of structure does a metal have?

Answer 41

A lattice structure

Question 42

What is graphene

Answer 42

A single layer of graphite, one atom thick

Question 43

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

Answer 43

excellent, low

Question 44

What can graphene be used to make?

Answer 44

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

Question 45

What are fullerenes

Answer 45

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

Question 46

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 ?

Answer 46

weak, between, low, weak, broken

Question 47

What can fullerenes be used for?

Answer 47

To deliver drugs, act as lubricants and as catalysts

Question 48

What are carbon nanotubes?

Answer 48

Cylindrical fullerenes

Question 49

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

Answer 49

strong, conductors, electrical, catalysts, tennis

Question 50

Why are catalysts often (attached to) carbon nanotubes?

Answer 50

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

Question 51

What are polymers

Answer 51

Long chain like molecules

Question 52

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

Answer 52

Polymer, strong, intramolecular

Question 53

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

Answer 53

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