inorganic chemistry

metal + water →

metal hydroxide + hydrogen

why do group 1 elements become more reactive as it goes down the group

alkali metals need to lose one electron to form a +1 ion

outermost electron is further from the nucleus as it gets bigger

less attraction between outermost electron and nucleus

outer electron is more easily lost as the atom becomes bigger

metal is more reactive

features of chlorine

poisonous green gas at room temperature

boiling point at -35°C

features of bromine

poisonous red-brown liquid at room temperature

boiling point at 60°C

features of iodine

dark grey solid at room temperature

purple vapour is given off when heated

boiling point at 180°C

what is the overall physical trend in halogens when you go down the group

the boiling point increases

the color gets darker

why do group 7 elements become less reactive as it goes down the group

halogens need to gain one more electron to become a -1 ion

less attraction between outermost shell and nucleus

because atom is bigger when element is further down the group

it gets harder to attract the extra electron

halogen is less reactive

displacement

a more reactive element displaces a less reactive element from a compound

reduction

gain of electrons

loss of oxygen

oxidation

loss of electrons

gain of oxygen

oxidizing agent

accepts electrons and becomes reduced

reducing agent

donates electrons and becomes oxidized

redox reactions

reactions where reduction and oxidation occur simultaneously

percentage of nitrogen in the air

78%

percentage of oxygen in the air

21%

percentage of argon in the air

nearly 1%

percentage of carbon dioxide in the air

0.04%

how to use iron to determine percentage of oxygen in the air

soak iron in acetic acid

push wool into a measuring cylinder and invert it into a beaker of water

record the starting position of water

the level of water will rise

leave the cylinder for a large period of time

record end position of water

why is iron soaked in acetic acid to determine the percentage of oxygen in the air

to catalyze the reaction

why does the water rise in the practical to investigate the percentage of oxygen in the air

the iron reacts with the oxygen in the beaker to make iron oxide

the water rises to fill the space that oxygen took up

formula to calculate percentage of oxygen

start volume - final volume / start volume x 100

how to use phosphorus to determine percentage of oxygen in the air

place phosphorus in a tube

attach a glass syringe at each end

heat phosphorus and use syringe to pass the air over it

as it reacts, the amount of air in the syringes will decrease

measure the starting and final volumes of air using a scale on one of the syringes

why does the air in the syringes decrease in the practical to investigate the percentage of oxygen in the air

the phosphorus reacts with the oxygen that is passed over it to produce phosphorus oxide

features of magnesium

burns with a bright white flame in air and forms white powder of magnesium oxide

alkaline when dissolved in water

features of hydrogen

burns easily in oxygen, can be explosive, and has a ‘squeaky pop‘

burns with an almost invisible pale blue flame and produces water

features of sulfur

burns in air with a pale blue flame and produces sulfur dioxide

acidic when dissolved in water

practical of thermal decomposition of metal carbonates

heat copper (II) carbonate in a tube that connects to a delivery tube

when heated, copper (II) carbonate produces copper (II) oxide and carbon dioxide

what color is copper (II) carbonate

green

what color is copper (II) oxide

black

thermal decomposition

breaking down substances using heat

human activity that affects the amount of carbon dioxide in the atmosphere

deforestation

burning fossil feuls

metal + acid →

salt + hydrogen

iron + oxygen + water →

hydrated iron (III) oxide

another name for rust

hydrated iron (III) oxide

what type of reaction is rusting

oxidation reaction

methods to prevent rusting

painting

oiling

sacrificial methods

sacrificial method to prevent rusting

zinc is often used as a sacrificial metal

zinc is more reactive than iron

zinc will be oxidized instead of iron

how do metals that are above carbon in the reactivity series get extracted

electrolysis

how do metals that are below carbon in the reactivity series gets extracted

reduction using carbon

by heating the ore with carbon monoxide

common qualities of iron, aluminum and copper

dense and lustrous

high melting points

strong and hard to break

malleable

good conductors of electricity and heat

properties of iron

corrodes easily

malleable

can change their properties when other materials are added

properties of aluminum

less dense than iron

doesnt corrode

reacts very quickly with oxygen and creates aluminum oxide, this layer of aluminum oxide sticks firmly to the aluminum below and stops any further reaction from occuring

properties of copper

good conductor of heat and electricity

what can iron be used for

gates and railings

what can aluminum be used for

drink cans

bicycle frames

aeroplanes

what can copper be used for

heating systems

electrical components and wiring

alloys

made by adding other elements to the metal

why are properties of alloys different from pure metals

different elements have different sized atoms

new atoms will distort the layers of metal atoms

making it harder for them to slide over each other

this makes alloys harder than pure metals

what color is phenolphthalein in acidic solutions

colorless

what color is phenolphthalein in alkaline solutions

pink

what color is methyl orange in acidic solutions

red

what color is methyl orange in alkaline solutions

yellow

what color is litmus paper in acidic solutions

red

what color is litmus paper in alkaline solutions

blue

what color is litmus paper in neutral solutions

purple

acids

source of hydrogen ions

are proton donors

bases

a substance that can neutralize an acid

are proton acceptors

alkalis

are soluble bases

source of hydroxide ions

neutralization chemical reaction

H⁺ + OH^- → H₂O

acid + ammonia →

ammonium salt

acid + metal carbonate →

salt + water + carbon dioxide

titration practical

use a pipette to add 25 cm³ alkali to a conical flask

add drops of indicator to flask too

fill a burette with acid

using the burette, add the acid to the alkali a bit at a time

swirl the flask periodically

the indicator changes color when all the alkali is neutralized

record the volume of acid used to neutralize the alkali

repeat process and get concordant results

are nitrates soluble

yes

are chlorides soluble

yes

except silver and lead chloride

are sulfates soluble

yes

except lead, barium, and calcium sulfate

are carbonates soluble

no

except sodium, potassium, and ammonium carbonates

are hydroxides soluble

no

except sodium, potassium, and calcium carbonates

are common salts of sodium, potassium, and ammonium soluble

yes

making insoluble salts

precipitation method

react two right soluble salts to create an insoluble salt

making lead sulfate

add lead nitrate to a test tube

add water to dissolve it

shake thoroughly to dissolve the lead nitrate completely

add magnesium sulfate to another test tube

add the two solutions into a beaker then stir

put filter paper into a conical flask

pour contents of beaker into flask

after emptying out the beaker, get the filter paper out of the conical flask and rinse the filter paper

scrape the lead sulfate onto fresh filter paper and leave it to dry

making soluble salts

heat acid in water bath in fume cupboard

add base to acid

produces soluble salt when base is in excess and all acid has been neutralized because te excess solid will sink to bottom of flask

filter excess solid to get a solution containing only salt and water

heat solution gently to slowly evaporate off some of water

leave solution to cool and allow the salt to crystalize

filter off solid salt and leave to dry

why would you heat acid in a water bath when making soluble salts

to speed up the reaction

why would you heat acid in a fume cupboard when making soluble salts

to avoid releasing acid fumes into the room

what color does lithium burn in cation test

red

what color does calcium burn in cation test

orange-red

what color does sodium burn in cation test

yellow

what color does copper burn in cation test

blue-green

what color does potassium burn in cation test

lilac

what color is the precipitate when copper (II) reacts with sodium hydroxide

blue

what color is the precipitate when iron (II) reacts with sodium hydroxide

sludgy green

what color is the precipitate when iron (III) reacts with sodium hydroxide

red-brown

ionic reaction of copper (II) and sodium hydroxide

Cu²⁺ + 2OH^- → Cu(OH)₂

ionic reaction of iron (II) and sodium hydroxide

Fe²⁺ + 2OH^- → Fe(OH)₂

ionic reaction of iron (III) and sodium hydroxide

Fe³⁺ + 2OH^- → Fe(OH)₃

what color is the precipitate when chloride ions reacts with silver nitrate

white

what color is the precipitate when bromide ions reacts with silver nitrate

cream

what color is the precipitate when iodide ions reacts with silver nitrate

yellow

how to test for halides

add dilute nitric acid

followed by silver nitrate

how to test for sulfates

add dilute hydrochloric acid

followed by barium chloride

what is the color of the precipitate of barium chloride

white

test for chlorine

bleaches damp blue litmus paper

test for oxygen

relights a glowing splint

test for carbon dioxide

turns limewater cloudy

test for hydrogen

makes a squeaky pop with a lighted splint

test for ammonia

turns damp red litmus paper blue

chemical test for water

water + anhydrous copper (II) sulfate → hydrated copper (II) sulfate

physical test for water

pure water boils at exactly 100°C and freezes at exactly 0°C

what color is anhydrous copper (II) sulfate

white

what color is hydrated copper (II) sulfate

blue

why can the chemical test for water be inaccurate

cant know if water is pure