Friday, 26 July 2013

9.6.1 HSC Q - Feedback


2004

b) You need to analyse the IMPACT – thus say that he studies electrolysis, made the laws and invented the terminology but also say how this impacted the knowledge/use of electrolysis – ie make a statement that it allowed electrolysis to be applied to industry, or that it allowed for greater ‘collaboration’ and communication between scientists which increased out understanding further…

2009

c) The flow chart arrows in the question are a clue that the scientists research is linked so you need to make the connections between them clear.

Galvani – animal electricity – Volta - disproved animal electricity with Voltaic pile – Davy – used voltaic pile for electrolysis – Faraday – devised the laws of electrolysis.

Key points to include (italics = optional)

Galvani – iron and brass in circuit touching nerve in frogs leg = jump = concluded jump caused by animal electricity from the muscle. Circuit produced was first recorded continuous current. Realised that metals were electrical conductors

Volta – made voltaic pile (describe) produced electricity sans-frog = disproved animal electricity. Proposed contact between metals as source of electricity. Realised current produced depended on the combination of metals (start of activity series). Voltaic pile = precursor to modern batteries and first reliable source of continuous current.

Davy – Used the voltaic pile to perform electrolysis of compounds – decomposed water and acids (ie water a compound, disproved Lavoisier), decompose molten salts to extract reactive metals (eg K) for the first time thus showed potential for electrolysis to be applied to scientific research and metal extraction for industry. Realised that electricity was decomposing compounds = breaking bonds = bonding must be electrical in nature. Realised it was reactions between electrode and electrolyte that were producing current in voltaic pile.

Faraday – Davy’s student/apprentice. Developed a device to measure charge passing through an electrolytic cell. Used this to devise the two laws of electrolysis (give). Quantitative laws meant electrolysis could be applied to scientific and industrial projects. Developed the terminology we use for electrochemistry (eg cation cathode, catholyte, electrolyte) allowed scientists to communicate/collaborate and further develop understanding of electrochemistry.

 

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