Summer Assessment 3

Question 1

what is the mass number the total of

Answer 1

Number of protons and neutrons

Question 2

how do you find out the number of neutrons

Answer 2

-subtract atomic number from mass number

Question 3

what is the Atomic Number

Answer 3

Number of protons

Question 4

what are molecules

Answer 4

-groups of atoms

Question 5

what is a group in the periodic table

-what do elements in the same group have in common

Answer 5

• Vertical column in the Periodic Table

- All elements in the same group have the same number of outer shell electrons and similar chemical properties.

Question 6

meaning of inert

Answer 6

Unreactive

Question 7

what are periods in a periodic table

Answer 7

-Horizontal row in the Periodic Table

Question 8

what group are the noble gases in

Answer 8

Group 0

Question 9

give 2 properties of the noble gases

Answer 9

• inert

- colourless gases

Question 10

why are the noble gases unreactive

Answer 10

-don’t have a full outer shell of electrons so arent desperate to give up/ gain electrons

Question 11

what are ionic compounds made up of

Answer 11

-a positively charged part and a negatively charged part

Question 12

name 5 properties of compounds with a giant ionic structure

Answer 12

• always have giant ionic structure
• ions held in closely packed 3D lattice arrangement
• electrostatic attraction between oppositely charged ions is very strong
• due to lots of energy needed to overcome the strong attraction- high melting and boiling point
• not electrical conductors when solid but are if melted/ dissolved in water

Question 13

name properties of a simple molecular substance

Answer 13

• atoms within molecule held together by very strong covalent bonds
• the forces of attraction between molecules = very weak
• this results in a low melting and boiling point as molecules are easily spereated
• most are gases or liquids at room temperature

Question 14

what happens to the melting and boiling point of simple molecular substances when the relative molecular mass increases

Answer 14

melting and boiling point increases as relative molecular mass increases

Question 15

name 4 properties of a giant covalent structure

Answer 15

• atoms are bonded to each other by strong covalent bonds
• lots of these bonds- lots of energy to break them- high melting and boiling point
• don’t conduct electricity- not even when molten`
• usually insoluble in water

Question 16

name the properties of diamond

Answer 16

• its made up of a network of carbon atoms that each form 4 fcovalent bonds
• strong covalent bonds take lots of energy to break so diamond has high melting point
• strong covalent bonds hold atoms in very rigid lattic structure so its really hard
• doesnt conduct electricity as it has no free electrons or ions

Question 17

name the properties of graphite

Answer 17

• each carbon atom only forms 3 covalent bonds creating layers of carbon atoms
• layers are held together by weak intermolecular forces of attraction- so can slide over each other- making graphite soft and slippery
• high melting point- covalent bonds in layers need lots of energy to break
• graphite has one delocalised electrong which is free to move- so it can conduct electricity

Question 18

briefly name the properties of diamond

Answer 18

• hard
• high melting point
• high boiling point
• cant conduct electricity

Question 19

briefly name the properties of graphite

Answer 19

• soft and slippery
• high melting point
• conducts electricity

Question 20

name the properties of C60 fullerene

Answer 20

• made up of large covalent molecules
• molecules held together by intermolecular forces that can slide over each other- hence why material is soft
• each carbon in C60 fullerene has a delocalised electron- however electrons cannot move between molecules so C60 fullerene is a poor conductor of electricity

Question 21

briefly name the properties of C60 fullerene

Answer 21

• soft

- poor conductor of electricity

Question 22

what is electric current and what does it cause to occur

Answer 22

• electric current = flow of electrons or ions

- when electrons/ ions move they cause material they are in to conduct electricity

Question 23

why can ionic compounds only conduct electricity when molten or in solution

Answer 23

• as solid ionic compounds dont conduct electricity as ions cannot move around
• however when ionic compounds are dissolved, ions are seperate and able to move so can conduct electricity
• when ionic compound melts- ions are able to move- so ions can conduct electricity

Question 24

what are metals held together by

Answer 24

-metallic bonding

Question 25

how are metals arranged

Answer 25

-have a giant structure of positive ions surrounded by a sea of delocalised electrons

Question 26

what is metallic bonding

Answer 26

the electrostatic attraction between the positive ions and the electrons

Question 27

why are metals good conductirs of heat

Answer 27

movement of electrons means energy can be transferred quickly through the material so metals are good conductors of heat

Question 28

why are metals good conductors of electricity

Answer 28

-as delocalised electrons are free to move through the structure- hence why metals can conduct electricity

Question 29

why are most metals malleable

Answer 29

-layers of ions in a metal can slide over each other- making metals malleable

Question 30

what do iron, aluminium and copper all have in common

Answer 30

• they are dense and lustrous (shiny)
• have high melting points
• have high tensile strength (strong and hard to break)
• malleable
• good conductors of electricity and heat

Question 31

what are the uses of iron

Answer 31

-its malleable- so used to make gates and railings

Question 32

what are the uses of aluminium

Answer 32

• doesn’t corrode- sp useful for products that come into contact with water (drink cans)
• much less dense than iron, so its lighter- useful for when the weight of the metal is important (bicycle frames and aeroplanes)

Question 33

what are the uses of copper

Answer 33

• good conductor of electricity- used in electrical components- so is efficient at transferring electricity
• good conductor of heat- used in heating systems- allows speedy transfer of heat to surroundings

Question 34

-what properties do pure metals have that aren’t always needed

Answer 34

-they are soft

-

Question 35

are nitrates soluble or insoluble

Answer 35

-soluble

Question 36

are common slats of potassium, sodium and ammonium soluble or insoluble

Answer 36

-soluble

Question 37

are common chloride soluble or insoluble

Answer 37

• soluble

- except for silver chloride and lead chloride

Question 38

are common sulfates soluble or insoluble

Answer 38

• soluble

- except for lead, barium and calcium sulfates

Question 39

are common carbonates soluble or insoluble

Answer 39

• insoluble

- except for sodium, potassium and ammonium carbonates

Question 40

are common hydroxides soluble or insoluble

Answer 40

• insoluble

- except for sodium, potassium and calcium hydroxides

Question 41

how do you make an insoluble salt

Answer 41

• use a preceipitation reaction

- react 2 soluble salts together to get an insoluble salt

Question 42

how do you make insoluble salt- lead nitrate

Answer 42

-add 1 spatula of lead nitrate to test tube

–add deionised water to dissolve it & shake thoroughly until its all dissolved

• in seperate test tube do the same with magnesium sulfate
• then tip the 2 solutions into small beaker & stir so its all mixed- lead sulfate should precipitate out
• fold filter paper in a filter funnel & put into conical flask
• pour contents of beaker into filter paper
• swill out beaker with more deionised water & tip into filter paper
• rinse contents of filter paper with deionised water
• scrape lead sulfate onto fresh filter paper & leave to dry in an oven