1. The problem statement, all variables and given/known data I am required to plan an investigation to find out how changes in the consumption of protein in the diet influences the excretion of urea in humans. Apparatus: 10g per 100cm3 (10%) solution of urea. Urease tablets or 5g per 100cm3 (5%) solution of urease 0.1moldm-3 hydrochloric acid pH indicators e.g. litmus paper ect School/ laboratory resources 2. Relevant equations I have been told that urea + water and urease makes ammonium carbonate and that I can use titration to find the concentration of urea. 3. The attempt at a solution I am going to use titration on various known concentrations of urea to make a calibration curve that can then be used on real urine samples. Q. Will making a calibration curve be of any use to people that are hoping to carry out the experiment as they would surley have to carry out titration anyway and therfore would have not much need to use the calibration curve as they will have practically done the whole thing themselves anyway?