3.5 - Metals

Question 1

What two components are in the structure of a metal?

Answer 1

-lattice of positive metal ions
-sea of delocalized electrons

Question 2

What is metallic bonding?

Answer 2

electrostatic attraction between the positive metal ions and the negative delocalized electrons

Question 3

Metallic bonding is a very…

Answer 3

strong attraction

Question 4

Give 3 properties of metals

Answer 4

-high MP
-conductors
-malleable

Question 5

Why are metals malleable?

Answer 5

layers of metal ions can slide over each other

Question 6

What is thermal decomposition?

Answer 6

heat energy is used to break down a substance

Question 7

THERMAL DECOMPOSITION: metal carbonate—>

Answer 7

metal oxide + carbon dioxide

Question 8

What is the thermal decomposition of copper carbonate?

Answer 8

copper carbonate —> copper oxide + carbon dioxide

Question 9

What is the colour change of the thermal decomposition of copper carbonate?

Answer 9

green solid —> black solid + colourless gas

Question 10

How is CO2 normally collected?

Answer 10

downward delivery - denser than air

Question 11

What 6 metals are the most reactive?

Answer 11

potassium, sodium, lithium, calcium, magnesium, aluminium

Question 12

What 3 metals are the least reactive?

Answer 12

gold, silver, copper

Question 13

What 3 metals have a medium reactivity?

Answer 13

lead, iron, zinc

Question 14

Metal + Water —>

Answer 14

Metal hydroxide + Hydrogen

Question 15

What two observations are made in a metal + water reaction?

Answer 15

-effervescence (hydrogen produced)
-solid disappears

Question 16

Group 1 metals are also known as…

Answer 16

alkali metals

Question 17

What 4 observations are made with alkali metal + water reactions?

Answer 17

-solid floats
-effervescence
-solid moves (fizzing propels water around water surface)
-solid disappears

Question 18

Are metal hydroxides acidic or alkaline?

Answer 18

alkaline - OH- donor

Question 19

What is observed in a potassium reaction with water?

Answer 19

lilac flame

Question 20

What is the group 1 reactivity trend?

Answer 20

-more reactive as you go down group
-atoms get BIGGER (more shells)
-outer shell electron is FURTHER FROM NUCLEUS
-ATTRACTION of outer-electron is WEAKER
-LESS ENERGY is needed to break the attraction

Question 21

Metal + Steam —>

Answer 21

Metal Oxide + Hydrogen

Question 22

What is an example of a metal + steam reaction?

Answer 22

-wet wool in a horizontal tube with magnesium ribbon
-heat causes wool to generate steam
-hydrogen is ignited to destroy it

Question 23

Acid + Metal —>

Answer 23

Salt + Hydrogen

Question 24

A salt is a compound formed when Hydrogen is…

Answer 24

displaced from an acid

Question 25

What are 2 observations made in an acid + metal reaction?

Answer 25

-metal disappears -fizzing (hydrogen)

Question 26

Test for hydrogen

Answer 26

lit splint - squeaky pop

Question 27

Magnesium + Copper sulphate --->

Answer 27

Copper + Magnesium sulphate

Question 28

What is the colour change of the solid in the displacement reaction of magnesium + copper sulphate?

Answer 28

grey solid ---> pink-orange solid

Question 29

What is the colour change of the solution in the displacement reaction of magnesium + copper sulphate?

Answer 29

blue solution ---> colourless solution

Question 30

Where are most metals found?

Answer 30

earth's crust - compounds with oxygen and sulphur (ORES)

Question 31

What 2 metals are too unreactive to have combined with oxygen or sulphur?

Answer 31

gold and silver - native

Question 32

How can ores be extracted by carbon extraction?

Answer 32

-metals LESS REACTIVE than carbon, can be displaced by carbon -e.g. copper carbon + copper oxide ---> carbon dioxide + copper

Question 33

What is a redox reaction?

Answer 33

reduction and oxidation in the same reaction

Question 34

What causes rust?

Answer 34

iron is oxidised (hydrated iron oxide)

Question 35

How does rust occur?

Answer 35

-iron is oxidized (gains oxygen + loses electrons) -iron oxide is hydrated by water

Question 36

What 3 methods prevent rusting?

Answer 36

-barriers -sacrificial protection -galvanising

Question 37

How does using barriers prevent rusting?

Answer 37

-paint, oil, grease -prevents iron coming into contact with oxygen or water

Question 38

How does galvanising prevent rusting?

Answer 38

-coating iron in zinc -coating prevents oxygen and water coming in contact -zinc is more reactive than iron so acts as sacrificial protection as well

Question 39

How does sacrificial protection prevent rusting?

Answer 39

-attach a more reactive metal (e.g. Mg) -displaces iron from rust as soon as rust forms -Mg block has to be replaced regularly

Question 40

What is the use of Fe and why?

Answer 40

use: making steel why: steel is more useful than Fe

Question 41

What is the use of low-carbon steel and why? (Fe + C)

Answer 41

use: ships, cars, bridges etc. why: strong, but low C so is malleable (can be hammered into different shapes)

Question 42

What is the use of high-carbon steel and why? (Fe + C)

Answer 42

use: tools (e.g. knives, screwdriver) why: less malleable (harder)

Question 43

What is the use of stainless steel and why? (Fe + C + Cr)

Answer 43

use: cutlery, cooking utensils why: Cr forms oxide layer that resists corrosion, stays shiny

Question 44

What is the use of Cu and why?

Answer 44

use: wires, cooking pans why: good conductor electricity, good conductor heat

Question 45

What is the use of Al and why?

Answer 45

use: power cables, aircraft bodies why: low density, conductor, strong