2. An amino acid with three ionizable functional groups can exist in different forms and histidine is an example. [17 pts.] (a) Draw the structures of the predominant ionization state of histidine at pH 1, 4, 8 and 12. Include the net charge on the histidine molecule in each ionization state. (b) Write the equilibrium equations for the three ionizable protons present in histidine an assign the proper pKa for each ionization.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

here are some of the ways in which chemical and nuclear reactions differ.

explanation: