Question

i need to write an expression that relates the disaperance of a to the deisapperance of B the reaction is 3A+B->2P

Answer 1

the balanced reaction tells us that for every molecule of B that reacts, 3 molecules of A are needed. The relative rates of disappearance will operate on the same ratio:

\[\frac{3\Delta[A]}{\Delta t} = \frac {\Delta [B]}{\Delta t}\]