PLEASE HELP!
I am trying to work out k in a the rate equation, rate=k[h202]^1[5% yeast catalyst]^1 in order to later determine the activation enthalpy but do not know what the concentration of the 5% yeast solution is in terms of mol/dm^-3. Does anyone know how I would do this?
Thanks

Question

PLEASE HELP! 
 I am trying to work out k in a the rate equation, rate=k[h202]^1[5% yeast catalyst]^1 in order to later determine the activation enthalpy but do not know what the concentration of the 5% yeast solution is in terms of mol/dm^-3. Does anyone know how I would do this? 
 Thanks

jfraser · Answer

it's probably 5% mass/volume, so every 100g of water contains 5g of yeast

anonymous · Answer

So would that mean it would be 5mol/dm3?

jfraser · Answer

definitely not

jfraser · Answer

is the starting concentration of yeast changed during the experiment, or just the peroxide?

jfraser · Answer

you may not actually need the concentration of yeast, but without more info I'm not sure

anonymous · Answer

but if it is first order with respect to yeast I would need to know the concentration of yeast

jfraser · Answer

then you would need to convert 5g of yeast into moles of yeast. You need to know the formula of the yeast to find its molar mass, and I'm not sure that yeast has a definite formula.

anonymous · Answer

okay thank you I will try and find a formula for it