metals

metals reacting with water

K - Ca: produces MOH + h2 at any temperature

Mg - Fe: only reacts with STEAM to produce MO + H2 (Not cold water)

Sn - Pt: no reaction

metals reacting with dilute acids

K - Pb: produces salt + h2

(H) Cu - Pt: no reaction

metal reacting with oxygen (air)

K - Ag - produces MO

Au & Pt: no reaction

metal oxide reaction boundaries with heat, hydrogen gas and carbon dioxide/carbon monoxide

action of heat: CuO and above (no reaction) HgO and below (produce M + O2)

action of H2: ZnO and above (no reaction) FeO / Fe2O3 and below(produce M + H2O)

action of C or CO: Al2O3 and below no reaction

ZnO and below (produce M + CO2)

metal carbonate + heat boundaries

only K and Na carbonate no reaction

the others produce decomposes to form MO + CO2

Hg and Ag decomposes to form M + CO2 + O2

metal nitrate + heat action

K and Na produces MNO2 + O2 (first 2 nitrates)

Ca - Cu produces MO + NO2 + O2

Hg + Ag: M + NO2 + O2 (last 2 nitrates)

metal reactivity ___ down a group

increases

precipitation reaction definition

2 aqueous salts react together to form an insoluble salt (ppt) and a soluble salt

aluminium appears unreactive, why?

because of a protective oxide layer, Al2O3

sandpaper it to remove the protective oxide layer

what is a displacement reaction?

the more reactive metal / halogen displaces the ions of the less reactive metal / halogen from its salt solution

explain why a metal displaces another metal in a reaction

A is more reactive than B. Hence, A displaces the B ions in [ionic compound] to form B metal (name the colour as well) and (ionic compound AX+ colour)

what colour is CuCO3

green

what colour is fe2o3

it is rust

reddish brown

what colour is CuO

black

what colour is Cu2O

reddish brown

what colour is CuCl2

green / bluish-green

what colour is iodine at diff states

black when solid

violet when vapour

yellowish-brown at lower concentrations / reddish-brown at higher concentrations when aqueous

what colour is flourine gas

pale yellow

what colour is nitrogen dioxide gas

reddish brown

what colour is KMnO4

purple → acidified solution turns colourless when reduced

what colour is K2Cr2O7

orange → solution turns green when reduced

what colour is KI

colourless → turns reddish brown when oxidised (iodine solution is formed)

phenolphthalein colours

colourless → pH 9 → pink

methyl orange colours

red/orang → pH4 → yellow

more reactive metals form … because …

more stable compounds that will not decompose easily to form back the metals

because they give out electrons more readily to form compounds with stronger ionic bonds between the oppositely charged ions

how to extract unreactive metals? name the metals too

Ag Au Pt

Since unreactive metals do not form compounds easily, they are commonly fond as elements

simply purify them by melting + skilling / filtration

how to extract moderately reactive metals?

commonly found as compounds - oxides / sulphides

1. turn sulfides into oxides by heating in air

2. heat oxides with carbon or carbon monoxide in a blast furnace

Zn to Cu

how to extract reactive metals?

K to Al

extracted from their molten ionic compounds by electrolysis

properties of mild steel

1. 0.25% carbon

2. strong and malleable

properties of hard steel

1. 1% carbon

   1. harder and less malleable

stainless steel properties

1. iron with large amounts of chromium and nickel

2. hard shiny and does not rust

what is rusting

corrosion of iron

iron reacts with oxygen in the air in the presence of water to form rust

rust consists of the compound hydrates iron (III) oxide

what are the ways to prevent rusting

1. coating the object with a layer of substance

   1. surface / barrier protection

2. attaching the iron with a more reactive metal that corrodes in the place of iron

   1. sacrificial protection

how does sacrificial protection work? (phrasing)

1. X is more reactive than Y

2. X will lose electrons more readily than Y

3. electrons will move from X to Y so X closes electrons faster and corrode faster (rusts in place of Y) and prevents Y from corroding

if two iron nails are attached to tin and copper each, which nail will corrode faster?

tin

tin is more reactive than copper, so it will lose electrons to iron more readily than copper

what happens when a barrier protection is broken?

the metal inside will be exposed to the environment and will start to rust faster than normal

because the metal inside is more reactive than the metal outside, so electron move from the inside metal to the outside metal, causing inside metal to lose electrons faster and rust faster

phrasing for sacrificial protection?

metal A is more reactive than metal B

A protect B fro rusting by corroding in place of B

why are metals malleable and ductile?

the layers of atoms in a metal can slide over each other easily

why do metals have high MP and BP?

a lot of energy is needed to overcome the strong metallic bonds between the sea of electrons and layer of cations

describe and explain the difference in physical properties between a pure metal and an alloy

alloys are much stronger and harder than pure metals because

in an alloy, the atoms of different metals have different sizes, which disrupts the orderly arrangement of layers of atoms and makes it harder for the layers to slide over each other (like it does in a pure metal)

what are alloys?

they are a mixture of metals with another element(s)

colour of copper chloride solution

blue green or green

colour of copper (I) oxide

reddish brown

colour of CuO oxide

black

colour of Fe2+ and Fe3+ solutions

green and red d

color of FeO and Fe2O3

FeO — black

Fe2O3 — reddish browtn

colour of KmnO4 and K2Cr2O7

purple and orange

turn colourless and green when reduced

colour of KI

colourless

turns reddish brown when oxidised (iodine solution is formed)

rank the following in terms of most reactive to least reactive

C > B > A > E > D

what charge is Sn

2+

is displacement reaction exothermic or endothermic

exothermic

what colour is fe3+ in higher and lower concentration

higher → reddish-brown

lower → yellowish brown

more reactive metals form…

more stable compounds

how does a metal nitrates’ products when reacting with heat tell us about their reactivity ?

nitrates of more reactive metals decompose to form nitrate of X and oxygen

nitrates of less reactive metals decompose to form metal X and

nitrates of middle reactivity decompose to form metal oxide, nitrogen dioxide and oxygen

Why X cannot be extracted from X oxide in the same way Y from Y oxide by reacting with hydrogen

State the obvious first:

X is more reactive than Y

X oxide is more stable than Y side

Hydrogen cannot react / reduce X from X oxide

What colour is PbO

yellow

observations and explanations of a displacement reaction format

observations:

• [colour] of solution gradually turned [colour]

• heat given off

• solid turned from [colour] to [colour] as [name of] solid is formed

explanation:

the yellowish brown colour comes from the X ions which are displaced by [metal atoms] to form X (metal). Displacement reaction is exothermic

Explain why aluminium does not corrode easily.

Aluminium reacts with oxygen in the air to form an insoluble layer of aluminium oxide. This layer protects the aluminium beneath it from corrosion / acts as a barrier from contact with air and water

explain how sacrificial protection works

X is more reactive than Z and loses electrons more readily than Z

when X is attached to the , electrons flow from X to Z in the ___.

this causes X to corrode more rapidly and prevents Z from corroding

so X corrodes in place of Z in ____.

what are the reactions in a blast furnace?

1. Coke: C + O2 → CO / CO2 (and then CO2 + C → 2CO)

2. Iron ore: Fe2O3 + 3CO (reducing agent) → 2Fe + 3CO2

removal of impurities:

1. Limestone: CaCO3 → CaO + CO2

2. SiO2 + CaO → CaSiO3 (calcium silicate / slag. floats above iron)