metals 3.5

Question 1

what’s the structure of metals?

Answer 1

1. a lattice of positive metal ions
2. sea of delocalised electrons - lost by metal ions so they move freely through lattice

Question 2

what’s the definition for metallic bonding?

Answer 2

metallic bonding is the electrostatic attraction between the positive metal ions and the negative delocalized electrons

Question 3

what types of atoms are involved in metallic bonding?

Answer 3

metal to metal ions

Question 4

what type of attraction is metallic bonding?

Answer 4

very strong attraction

Question 5

why do metals tend to have high melting points?

Answer 5

as metallic bonding is very strong and lots of energy is needed to break it

Question 6

why can metals conduct electricity?

Answer 6

as delocalised electrons are free to move through the lattice

Question 7

why are metals malleable?

Answer 7

as the layers of metal ions can slide over each other

Question 8

what’s thermal decomposition?

Answer 8

when heat energy is used to break down a substance

Question 9

what’s the equation for metal carbonate decomposition?

Answer 9

metal carbonate > metal oxide + carbon dioxide

for example
copper carbonate > copper oxide + carbon dioxide

Question 10

what’s the colours involved with the decomposition of metal copper carbonate?

Answer 10

copper carbonate (green solid) > copper oxide (black solid) + carbon dioxide (colourless gas)

Question 11

what’s downwards delievery?

Answer 11

carbon dioxide is denser than air so it is collected in a downwards delivery
as it sinks to the bottom of the tube and stays there until you want to use it

Question 12

what are the most reactive metals?

Answer 12

K
Na
Li
Ca
Mg
Al

Question 13

what the reaction of metal and water?

Answer 13

metal + water > metal hydroxide + hydrogen

for example
magnesium + water > magnesium hydroxide + hydrogen

Question 14

what two observations can be made about the metal + water reaction?

Answer 14

effervescence - due to the hydrogen gas being produced
solid disappears - due to it being used up in the reaction

Question 15

what are group 1 metals called?

Answer 15

alkali metals

Question 16

how do group 1 metals react in the metal + water reaction?

Answer 16

react violently with the water

metal + water > metal hydroxide + hydrogen

for example
lithium + water > lithium hydroxide + hydrogen

Question 17

what’s some of the observations of the group 1 metals and water reaction?

Answer 17

solid floats - less dense than water
effervescence - hydrogen gas in produced
solid moves - effervescence propels it around the surface of water
solid disappears - used up in reaction

Question 18

what happens if a universal indicator is added to the water after the group 1 metals + water reaction?

Answer 18

turns dark blue as metal hydroxides are alkalis as they donate OH-

Question 19

what is metal hydroxides?

Answer 19

alkalis
donate OH-

Question 20

what’s the reactions of Li, Na, K in the group 1 metals + water reaction?

Answer 20

Li - fast
Na - faster, Na melts
K - fastest, K melts, lilac flame

Question 21

what’s the reactivity trend of group 1 metals?

Answer 21

get more reactive as you go down the group

Question 22

why do group 1 metals get more reactive as you down the group?

Answer 22

• atoms get bigger and have more shells
• outer shell electron is further from nucleus
• attraction between nucleus and outer shell electron is weaker
• less energy is needed to break the attraction

Question 23

what the metal + steam reaction?

Answer 23

metal + steam > metal oxide + hydrogen

for example
magnesium + water > magnesium oxide + hydrogen

Question 24

how is the metal + steam reaction conducted?

Answer 24

in a horizontal tube with wet wool
a metal
causes H2 to become on fire
wet wool is heated to generate steam for metal to react with
H2 gas is ignited to safely destroy it

Question 25

why do metals react differently with cold water vs hot steam?

Answer 25

steam has more energy so both bonds in the water molecule can break

Question 26

what’s the metal + acid reaction?

Answer 26

acid + metal > salt + hydrogen for example magnesium + sulphuric acid > magnesium sulphate + hydrogen

Question 27

how is salt formed in an acid + metal reaction?

Answer 27

a H from the acid is displaced

Question 28

what is the formula for hydrochloric acid? what salt does it form?

Answer 28

HCl metal chloride

Question 29

what is the formula for sulphuric acid? what salt does it form?

Answer 29

H2SO4 metal sulphate

Question 30

what is the formula for nitric acid? what salt does it form?

Answer 30

HNO3 metal nitrate

Question 31

what is the formula for phosphoric acid? what salt does it form?

Answer 31

H3PO4 metal phosphate

Question 32

what’s two observations in the acid + metal reaction?

Answer 32

metal disappears - used up in reaction fizzing - as the gas hydrogen is produced

Question 33

what acids can’t you use in an acid + metal?

Answer 33

too reactive : K, Na, Li unreactive : Au, Ag, Cu

Question 34

what’s the chemical test for hydrogen?

Answer 34

lit splint > squeaky pop in a test tube of hydrogen as the combustion of hydrogen causes test tube to resonate

Question 35

what’s a metal displacement reaction?

Answer 35

when more reactive metals can displace less reactive metals for example magnesium + copper sulphate > copper + magnesium sulphate

Question 36

what’s the observation for metal displacements?

Answer 36

solid colour change solution colour change magnesium (grey solid) + copper sulphate (blue solution) > copper (pink-orange solid) + magnesium sulphate (colourless solution)

Question 37

ores and natives what are they?

Answer 37

most metals are found in earth’s crust as compounds with oxygen and sulphur native metals exist on their own as they are too unreactive to have combined with oxygen or sulphur

Question 38

using electricity to extract metals in ores:

Answer 38

metals more reactive than carbon cannot be displaced by carbon so we use electricity

Question 39

using carbon extraction to extract metals in ores:

Answer 39

metals less reactive than carbon are displaced by carbon heat up the ore with carbon

Question 40

what’s a reducing agent?

Answer 40

take away something from something else (this could be oxygen)

Question 41

what’s an oxidising agent?

Answer 41

gives something to something else (this could be oxygen)

Question 42

what’s reduction?

Answer 42

the loss of substance

Question 43

what’s oxidation?

Answer 43

gain of substance

Question 44

what is rusting?

Answer 44

a chemical process in which iron is oxidised to form rust

Question 45

what is the chemical name for rust?

Answer 45

hydrated iron(|||) oxide iron (grey, shiny, malleable) > iron (|||) oxide > hydrated iron (|||) oxide (brown, dull, brittle)

Question 46

what two substances does rusting require?

Answer 46

- iron is oxidised by OXYGEN iron(|||) oxide - hydrated by water hydrated iron(|||) oxide

Question 47

what are the methods that prevent rusting?

Answer 47

using barriers sacrificial protection galvanising

Question 48

using barriers to prevent rusting:

Answer 48

coating iron in paint, oil, grease or plastic preventing iron from coming in contact with oxygen or water works as long as coating is intact if coating breaks = rusting happens

Question 49

using sacrificial protection preventing rusting:

Answer 49

attach a block of a more reactive metal to the iron this works by displacing the iron from rust as soon as rust forms block of reactive metal (magnesium) has to be replaced often

Question 50

using galvanising to prevent rusting:

Answer 50

involves coating the iron in zinc - casting prevents O2 and H2O from coming in contact with iron - zinc is more reactive than iron so acts as sacrificial protection too

Question 51

what are alloys?

Answer 51

mixtures of a metal with one or more other elements, usually other metals or carbon

Question 52

commonly known alloys steel:

Answer 52

iron + copper

Question 53

commonly known alloys brass:

Answer 53

copper + zinc

Question 54

commonly known alloys bronze:

Answer 54

copper + tin

Question 55

why are alloys harder than pure metals?

Answer 55

as they contain different sized ions/atoms preventing the layers of metal ions from sliding over each other meaning alloy is less malleable

Question 56

use of iron and elements:

Answer 56

Fe making steel - steel is more useful than iron

Question 57

use of low carbon steel and elements:

Answer 57

Fe and C ships, cars, bridges etc - strong -can be hammered into various shapes

Question 58

use of high carbon steel and elements:

Answer 58

`Fe and C tools, knives, screwdrivers etc - less malleable -stiff

Question 59

use of stainless steel and elements:

Answer 59

Fe, C and Cr cutlery, cooking utensils, kitchen sinks - Cr forms oxide layer that resists corrosion - stays shiny and clean

Question 60

use of copper and elements:

Answer 60

Cu wires, cooking pan, water pipes - excellent conductor of electricity - excellent conductor of heat - unreactive and malleable

Question 61

use of aluminium and elements:

Answer 61

Al aircraft bodies, power cables - low density and high strength - low density and conducts