How do you calculate the rate of reaction between potassium bromate and bromide ions (using sulphuric acid)?
If there is a color change you could time it manually with a stopwatch, or even do a series of scans using a spectrometer to see how absorbance varies with time. Obviously the colder the reaction, the slower it will go, and the higher the concentration, the faster it will go. You can figure out if it is a first order reaction or not from that.
