general

Question 1

5 properties of compounds

Answer 1

1. constituent elements are in a fixed ratio
2. energy is usually taken or released during formation
3. properties are very different from the properties of its constituent elements
4. sharp boiling and melting points
5. can only be separated by chemical methods

Question 2

5 properties of mixtures

Answer 2

1. substances in a mixture can be mixed together in any proportion
2. no/little energy change during formation
3. properties similar to that of its substances
4. don’t have a sharp boiling and melting point
5. constituents can only be separated by physical methods

Question 3

5 properties of mixtures

Answer 3

1. substances in a mixture can be mixed together in any proportion
2. no/little energy change during formation
3. properties similar to that of its substances
4. don’t have a sharp boiling and melting point
5. constituents can only be separated by physical methods

Question 4

half equation

Answer 4

electron gains (17e- to 18e-) on the left, losses on the right (10e- to 9e-)

Question 5

different ages

Answer 5

stone, copper, bronze, iron

Question 6

metal extraction

Answer 6

K, Na, Ca, Mg, Al: electrolysis of molten ores
Zn, Fe, Pb, Cu: sulphides heated in air to obtain oxides, oxides heated with carbon to obtain metals
Cu, Hg, Ag: sulphides heated in air to obtain metals
Ag, Pt, Au: exist freely in nature

Question 7

4 extraction methods

Answer 7

1. metal + oxygen —heat—> metal oxide (all except Ag, Pt, Au)
2. metal + cold water ——> metal hydroxide + hydrogen gas (first three, K, Na, Ca)
3. metal + steam ——> metal oxide + hydrogen gas (first five + zinc, iron)
4. metal + dilute acid ——> metal salt + hydrogen gas (first five + zinc, iron, lead)

Question 8

most reactive metals: most unreactive compounds, hardest to extract from their ores

Question 9

positive electrode (anode) 🔴
negative electrode (cathode) 〰️

Question 10

aluminium (3)

Answer 10

1. strong, low density —-> making aircraft bodies
2. good conductor of heat, malleable —> making kitchen foil
3. low density, cheap —> overhead cables

Question 11

copper (1)

Answer 11

1. good conductor, ductile: making electric wires

Question 12

gold (1)

Answer 12

1. shiny, malleable, ductile: making jewellery

Question 13

iron (1)

Answer 13

1. good conductor of heat, high melting point: cooking utensils

Question 14

lead (1)

Answer 14

1. very dense: fishing sinkers

Question 15

definition of alloy

Answer 15

a mixture of a metal and one or a few other elements. usually made by heating the metal and other elements together, causing them to melt and mix

Question 16

carbon steel (1)

Answer 16

iron, carbon
1. stronger than iron, more resistant to corrosion —> making motor car bodies, construction materials

Question 17

titanium alloy

Answer 17

titanium, aluminium, vanadium
1. very strong, low density —-> making aircraft bodies, spacecraft bodies, glasses frames

Question 18

bronze

Answer 18

copper, tin
1. more corrosion resistant, harder than copper —> making statues

Question 19

brass

Answer 19

copper, zinc
harder than copper and zinc, more resistant to corrosion —> making musical instruments, making door knobs and keys

Question 20

duralumin

Answer 20

aluminium, copper, manganese, magnesium
stronger than aluminium, low density —> making aircraft bodies

Question 21

coinage metals

Answer 21

copper, zinc, nickel, tin
harder and shinier than copper, resistant to corrosion
making coins

Question 22

carat gold

Answer 22

gold, silver and copper
harder and shinier than pure gold
making ornaments, coins

Question 23

solder

Answer 23

tin, lead
has a lower melting point but is harder
for joining electronic parts in circuit boards

Question 24

more molecules

Answer 24

higher boiling point
darker shade of yellow
more viscous
less volatile
less flammable
more black smoke produced when burning

Question 25

lower levels to higher levels

Answer 25

hotter to cooler higher boiling point = higher condensation point= larger molecules

Question 26

lower levels to higher levels

Answer 26

hotter to cooler higher boiling point = higher condensation point= larger molecules

Question 27

crude oil fractions

Answer 27

LPG, petrol (gasoline), naphtha, kerosene, diesel oil, fuel oil, lubricating oils and waxes, bitumen

Question 28

lpg (2) (under 40)

Answer 28

1. domestic fuels 2. fuel for taxis and public light buses

Question 29

petrol (gasoline) 2 (40-70)

Answer 29

fuels for motor cars

Question 30

naphtha (1) (70-170)

Answer 30

1. raw material for production of town gas, plastics and other chemicals

Question 31

kerosene (2) (170-250)

Answer 31

1. fuels for aeroplanes 2. used as solvents

Question 32

diesel oil (1) (250-350)

Answer 32

1. fuel for heavy vehicles such as lorries and buses

Question 33

fuel oil (2) (over 350)

Answer 33

1. fuel for ships 2. used to generate electricity in power plants

Question 34

lubricating oils and waxes (over 350

Answer 34

1. used to make lubricating oils and candles

Question 35

bitumen (over 350)

Answer 35

material for covering roads