Chemistry Flashcards
Group 7 properties Reactivity Melting point Boiling point Electronegativity
Less reactive High melting point Higher boiling point Electronegativity decreases (astract pair of electrons)
Halogen order and colours
Fluorine - yellow gas
Chlorine - dense green gas
Bromine- red/brown volatile liquid
Iodine- dark grey crystalline solid or purple vapour
What happens when more reactive halogen reacts with a less reactive halogen salt?
Ir displaces it
Higher up group displaces
What is volatility?
How easily a liquid evaporates
What is a mixture?
When a solid(solute) and a liquid (solvent) are added together and bonds between solvent break and solute mixes with liquid =solution
What is a solution?
A mixture of solute and solvent that does not separate out
What is a solute?
Substance being dissolved
What is the solvent?
The liquid it’s dissolveing into
What is soluble?
Means it will dissolve
What is the solubility?
How much it will dissolve
Nail varnish solubility in water?
Insoluble, attraction between nail varnish molecules is stronger than that between it and water and vice versa
Nail varnish in acetone?
Soluble (nail varnish remover) stronger atteactoon between nail varnish and acetone
How can you remove a metal from an ore?
Reduction by carbon (if less reactive)
Electrolysis
Displacement (other metal is more reactive)
What is electrophillic addition?
Double bond is attacked by electrophiles (positive ions or polar molecules)
Conditions for polymerisation?
Pressure
Catalyst
Temp and pressure effect polymer formed
What is non biodegradable?
Won’t rot
Alcohols react with sodium?
To give alkoxides
Uses of alcohols?
In cells to dissolve fats etc
Perfume
Clean paint brushes
Fuel
Carboxylic acid functional group?
COOH
Carboxylic acid and carbonate?
Co2+ Oate + water
Uses of carboxylic acids?
Dissolved in water=vinegar
Citrix scud
Soaps and detergents
Prep of esters
Solvent for organic molecules
What is hard water?
Contains ca 2+ or mg2+
Reacts with soap =scum
When boiled forms scale
Ca good for teeth
Less risk of heart disease
What is the difference between temporary and permanent hardness?
Temporary = hydrogencarbonate ions
Permanent= calcium sulphate
How to remove hardness?
Temporary - boiling
Either- exchange columns containing Na+ or H+
Flame test for
Lithium Sodium Potassium Calcium Barium Ions
Crimson Yellow Lilac Red Green
Test for chlorine!
Bleaches damp litmus paper (red to white)
Test for oxygen?
Relighted a glowing splint
Test for hydrogen
Squeaky pip with lighted splint
Test for metal ions?
Results of Calcium Copper ii Iron ii Iron iii Aluminium Magnesium
NaOH
White Blue Green Brown White - redesolves in excess White
Test for carbonates
Bubbling through lime water
Goes cloudy
Test for halides
Add nitric acid the silver nitrate
Cl=white
Br=cream
I=yellow
Test for sulphate?
AddHCl then BaCl2
White precipitate (bariumsulphate)
What if metal ions and hydrogen ions present?
Metal ions stay in solution and hydrogen forms at negative electrode unless metal is less reactive
If OH and halide ions are present?
Halide will form, if not there then oxygen will
Positive electrode
How to electroplate?
Negative electrode is the metal object that wants plating
Positive electrode is pure metal you want it plated with
Metal ions travel to negative electrode
Metal ions leave positive electrode
Electroplating silver?3
Silver nitrate
Electroplating copper?
Copper sulphate
How to separate insoluble solids?
Filtration and crystallisation
Ionic compounds properties?
High melting point High boiling point Carry electric charge when molten Dissolve easily Carry electric current in solution
Alkali metal properties?
Shiny when freshly cut but tarnish as they react with oxygen in moist air
Reactivity increases
Higher density
Lower melting point
Lower boiling point
React with water to produce hydrogen gas and hydroxide metal
Form ionic compounds with non metals
Halogen properties
Decrease in reactivity
Melting and boiling point increase
Electronegativity decreases
React with alkali metals to form salt
Higher up displace lower in ionic
Colours of halogens
Fluorine= yellow gas (poisonous and v reactive)
Chlorine=dense green gas (fairly reactive and poisonous)
Bromine=red/brown volatile liquid (dense and poisonous)
Iodine=dark grey crystaline solid or purple vapour
How to make bleach?
Mix sodium hydroxide with chlorine gas
Properties of noble gases?
Inert
Colourless gas
Boiling point increases
Density increases
Uses of argon?
Inert atmosphere in filament lamps
Protect metals that are being welded
Inert atmosphere prevents reacting with oxygen
Uses of helium?
Airships and balloons
Less dense than air so they float
What is sand?
Silicon dioxide
What is mass spectrometry used for?
To find the Mr
A molecular ion is made when bombarded with electrons to remove one = highest mass furthest to the right
Equation for % mass?
Ar x number of atoms/Mr of whole compound
X100
