[shama]

hello I couldn't solve a problem In Alfred Martin's book for physical pharmacy , I really don't get the problem and If you can help me to understand it.. it is ;
Cyclophosphamide monohydrate is available as a sterile blend of dry drug and sodium chloride packaged in vails. A suitable aqueous vehicle is added and the sterile powder dissolved with agitation before the product is used parenterally.. However Cyclophosphamide monohydrate is only slowly soluble in water and a hospital pharmacist inquiers concerning the advisability to briefly for 15 min. warming the soln. to 70 C to .. Assuming that the degradation to 95% of the labeled amount is permitted for this compound, and given k at 25 C=0.028 day^-1 , E_a= 25.00 Kcal/mole, what answer would you give

first i don't understand the answer the writer wants ,, i tried to calculate the time half but i could't .

[Borek]

You are given activation energy - that'll let you calculate rate coefficient k for 70 deg C (Arrhenius equation). You can than use this value to calculate how much cyclophosphamide will get decomposed during 15 minutes heating - although you must take care about time units used.