Metals and the Reactivity series

Question 1

reactions of metals with dilute acids

Answer 1

acid + metal -> salt + hydrogen
hydrochloric acid + calcium -> calcium chloride + hydrogen

Question 2

reactions of metals with cold water

Answer 2

water + metal -> metal hydroxide + H
water + lithium -> lithium hydroxide + H

Question 3

reactions of metals with steam

Answer 3

water (g) + metal -> metal oxide + H
water (g) + magnesium -> magnesium oxide + H

Question 4

reactions of metals with oxygen

Answer 4

oxygen + metal -> metal oxide
oxygen + magnesium -> magnesium oxide

Question 5

use of aluminum because of its physical properties

Answer 5

• manufacture of aircraft (low density)
• overhead elec cables (low density/elec conductor
• food containers (resistance to corrosion)

Question 6

use of copper because of its physical properties

Answer 6

electrical wiring (good elec conductor/ ductility

Question 7

order of reactivity

Answer 7

potassium, sodium, calcium, magnesium, aluminum, carbon, zinc, iron, hydrogen, copper, silver, gold

(please send clever monkeys and cheerful zebras in hydrogen cages secretly guarded.)

Question 8

reactions of K, Na, Ca with cold water

Answer 8

K - vigorous effervescence (hydrogen is produced), metal floats, gets smaller as reacts, gas ignites, lilac flame
Na - similar but less vigorous so hydrogen may not ignite
Ca - metal sinks, bubbles produced, metal disappears, solution is cloudy

Question 9

reactions of Mg with steam

Answer 9

Mg - reacts rapidly, becomes bright white

Question 10

reactions of Mg, Zn, Fe, Cu, Ag, Au with dilute acids

Answer 10

Mg - bubbles form, disappears quickly
Zn - bubbles form slowly
Fe - bubbles so slow hard to observe
Cu - no reaction
Ag - no reaction
Au - no reaction

Question 11

what do you need for rusting in steel or iron to happen

Answer 11

oxygen and water in the air

Question 12

painting

Answer 12

create polymer based coating layer that excludes any oxygen or water form getting in, preventing it from corrosion

Question 13

greasing

Answer 13

reduces friction and excludes oxygen and water from entering

Question 14

coating it with plastic

Answer 14

creates a thick polymer coating that prevents oxygen and water from entering

Question 15

why does aluminum not rust

Answer 15

because when it does corrode, the oxide layer that forms on the surface, protects the metal underneath it from more corrosion (corrosion resident, therefore unreactive)

Question 16

sacrificial protection

Answer 16

is when you protect a metal (like iron) from corrosion, by allowing a more reactive metal corrode instead. the metal needs to be more reactive than iron, so iron is protected

Question 17

galvanizing

Answer 17

when iron or steel is coated with a layer of a more reactive metal like zinc

Question 18

the relative reactivities of metals

Answer 18

is because of their tendency to form positive ions by displacement reactions