Quick Revision - Clock reactions

Essentials of how clock reactions can be used to measure the initial rate of a reaction followed by an exam question

[eesha]

Very useful thank you! I never understood clock reactions!

[rafiatbm]

Please explain why didn't you add sodium thiosulphate?? This reactions under acidic conditions are extremely fast for our reflexes to precisely measure the time taken each time for the solution to go to blue... That's why we add equimolar sodium thiosulphate at each trial, but you didn't... can you explain why ??

[ArmanTheLegend]

Can this come up in paper 1 and what part of the spec is this?

[kirensanthosh]

Would h2o2 + I --> h2Io2 be a suitable RDS for questions 3?

[shahidiqbal]

Aren't you supposed to have an excess of h+ and I- to keep their conc. constant?

[darkmoon]

Can u make one on continuous monitoring please

[belindaowiredu]

if we didn't include adding a small amount of starch in our answer and said measure the time for the reaction to be complete instead of measure the time taken for blue black colour to form would we still get the marks or be marked down?

[amelieharris]

why is the initial rate 1/time not moldm-3s-1?

[josiebaldwin]

can you draw a concentration-time graph or does it have to be rate-concentration?

[NA-bbbq]

for a first order conc-time graph, how could it go through the origin? Doesnt it decrease with a constant half life ???