Elements Of The sea Flashcards
What are the group 7 elements
Halogens
As you go down the group, what happens to the thermal stability, physical appearance, states, reactivity, volatility, mp/bp
Thermal stability decreases Becomes darker in colour Gases to liquids to solids Reactivity decreases Becomes less volatile Mp/bp increases
What is a reducing agent
It’s been oxidised and it reduces another ion
What are spectator ions?
Ions that don’t change in a reaction
What is a displacement reaction?
What displaces each other in group 7?
When an atom pushes out another atom and takes its place
Chlorine displaces bromine and iodine
Bromine displaces iodine
What are the colours formed when halogens react with silver to form silver halides?
+ when ammonium solution is added?
Chlorine - White
Bromine - Cream
Iodine - Pale yellow
Chlorine - clear
Bromine - cloudy/bit clear
Iodine - insoluble
O I L R I G?
Oxidation Is Loss Reduction Is Gain
What are oxidation states useful for?
- Naming inorganic compounds
- Deciding what has been oxidised and what has been reduced
- identifying the oxidising agents and reducing agents
- balancing redox reactions
What is the oxidation states for :
- Element
- Simple ion
- Compound
- Complex compound
- 0
- the charge on the ion
- charges add to 0
- charges add to charge on the compound
What is electrolysis?
When electricity is passes through a molten or aqueous ionic compound, the compound is broken down and the process is called electrolysis
What Is reduced at the cathode when there’s a group 1/2 metals present?
Hydrogen
2H2O + 2e —> 2OH- + H2
(If other metals then the metal is reduced.)
(Hydrogen if acid)
What is oxidised at the anode if the salt is a halide?
Halogen
Oxygen if sulfate or nitrate
(Oxygen is alkali)
Kc - constant
What is the equation?
[A]a [B]b
Products
___________
Reactants
Risks of chlorine?
Toxic gas
Irritant to eyes, skin, respiratory system
Reacts with lungs to for, HCl which effects the tissues
How is chlorine transported?
Uses pressurised tank containers In liquid to store more If pressure or temp too high, the tanks has pressure release devices to vent the tank and releases Cl as a gas The tank if made and lined with steel Dry so doesn't react with anything
Uses of chlorine
Water treatment
Household bleach
Remove stains on clothing
What is atom economy and what is the equation?
It’s the percentage of reactants that end up in the desired products
Atom economy = Mr of desired product / Mr of reactants x 100
How do u make hydrogen halides?
HCl = sodium chloride + sulfuric acid as it's not a strong enough reducing agent HBr = sodium bromide + phosphoric acid as its a strong enough reducing agent to reduce sulfuric acid to sulfur dioxide HI = sodium iodide + phosphoric acid as it reduces sulfur dioxide to hydrogen sulfide
What happens if: Pressure increases Temperature increases Temperature decreases Pressure decreases
Side with fewer gas moles
Endothermic direction
Exothermic direction
Side with more gas moles
If concentrations of : Reactants increase Reactants decrease Products increases Products decrease
The equilibrium moves to the Products side Reactants side Reactants side Products side
What is the trend in thermal stability and acidity as you go down the group?
Thermal stability decreases
HCl HBr HI are very acidic
What is the reaction with halogens and ammonia?
Glass rid dipped in ammonia solution and put it near halogen and a white cloud of ammonium halide is made.
