what I need to learn

 use the polystyrene cup experiment to measure energy released in a chemical reaction of neutralisation, metals and acids or carbonates and acids. or what effect different vairables have on energy transfer.

put in a beaker of cotton wool for insulation and put a lid on for energy lost from evaporation.

reaction profiles show the relative energies of reactants and products change over the course of the reaction.

endothermic- energy needed to break existing bonds

exothermic- energy released when new bonds are formed

electrochemical cell has two electrodes in contact with an electrolyte (contains ions that react with electrodes). the reaction sets up a charge difference. if electrodes are connected by a wire, charge can flow and electricity is produced.

electrolyte will change charge because different ions act differently with the metals.

battery is formed from joining two or more cells together in series.

non rechargable batteries(alkaline)- reactants get used up and turn into the products , irreversible reaction.

recharge rechargables by connecting to an external electric current.

fuel cell- when fuel enters cell it gets oxidised and sets up a pd within the cell

hydrogen-oxygen fuel cell combined hydrogen and oxygen to produce clean water and release energy.

electrolyte is usually potassium hydroxide. electrodes porous carbon with a catalyst.

hydrogen goes in anode compartment and oxygen in the cathode compartment.( opposite to PANIC)

at anode hydrogen loses electrons to be oxidised (OILRIG) they then move to the cathode.

at cathode oxygen gains electrons and reacts with the hydrogen to produce water. this is reduction

electrons flow through external circuit from anode to cathode.

not polluting, batteries need to be recharged often,batteries are more expensive to make

hydrogen gas needs space to be stored,explosive soo dangerous,hydrogen fuel made from hydrocarbons (FF) or electrolysis which uses electricity( usually from FF)