Elements from the sea

Question 1

How are Oxidation and reduction defined in terms of movement of electrons

Answer 1

oxidation is loss of electrons

reduction is gain of electrons

Question 2

Are state symbols used in redox half equations

Answer 2

No

Question 3

Which side of the equation are the electrons on for a half equation showing an oxidation process

Answer 3

Products side

Question 4

Which side of the equation are the electrons on for a half equation showing a reduction process?

Answer 4

the reactants

Question 5

What is meant by an ‘oxidising agent’ and a ‘reducing agent’?

Answer 5

describe the reactants in redox reactions that transfer electrons between reactants to form products

• oxidising agent gains electrons and is reduced
• reducing agent loses electrons and is oxidised

Question 6

what are the main uses of chlorine

Answer 6

domestic
- bleach/ disinfectant
-in swimming pools

Question 7

What state are the hydrogen halides found in at RTP (apart from HF)?

Answer 7

Colourless gas

Question 8

How can hydrogen halides be prepared from solid metal halide compounds, e.g. HBr from NaBr?
What is observed during the synthesis of hydrogen halides in this way?

Answer 8

addition of conc sodium acid (HCl) or phosphoric acid (HI, HBr),

Steamy fumes

Question 9

What is produced (and hence observed) when concentrated sulfuric acid is added to a substance containing:
➢ chloride ions? (or hydrogen chloride)
➢ bromide ions? (or hydrogen bromide)
➢ iodide ions? (or hydrogen iodide)

Answer 9

HCl- No reaction
HBr- Bromine (orange gas) water and sulfur dioxided
HI- Iodine ( purple gas) water and sulfur dioxide