<span>The theoretical yield for a reaction is calculated based on the limiting reagent. This allows researchers to determine how much product can actually be formed based on the reagents present at the beginning of the reaction.</span>
<span>The actual yield will never be 100 percent due to limitations.</span>
When carrying out experiment in the laboratory to investigate physical changes, absolute measurement is usually not needed. For instance, one can just take a little sample of sodium chloride and dissolve it in water to demonstrate physical change. But for other experiments, such as the measurement of the catalase enzyme activity in a liver tissue. Careful measurements have to be made when preparing the chemicals that will be used in the experiment.
Answer : The concentration of guanosine in your sample is, 
Explanation :
Using Beer-Lambert's law :

where,
A = absorbance of solution = 0.70
C = concentration of solution = ?
l = path length = 1.00 cm
= molar absorptivity coefficient guanosine = 
Now put all the given values in the above formula, we get:


Thus, the concentration of guanosine in your sample is, 