Urea (NH2)2CO carries amine (ammonia) generated by the catabolism of amino acids. Assume the natural abundance of 14N is 100%. Citrulline (Exam Images Sheet) is synthesized with 15N in both nitrogen atoms (assume 100%). The citrulline enters into the urea cycle. Approximately what percentage of nitrogen in the urea produced in one turn of the cycle contains a 15N, assuming the naturally occurring nitrogen isotope is 100% 14N?

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.