Answer : The original concentration of copper (II) sulfate in the sample is, 
Explanation :
Molar mass of Cu = 63.5 g/mol
First we have to calculate the number of moles of Cu.
Number of moles of Cu = 
Now we have to calculate the number of moles of 
Number of moles of Cu = Number of moles of
Number of moles of = 
Now we have to calculate the molarity of
Now put all the given values in this formula, we get:
To change mol/L into g/L, we need to multiply it with molar mass of
Molar mass of = 159.609 g/mL
Concentration in g/L = 
Thus, the original concentration of copper (II) sulfate in the sample is,
H2SO4 + 2KOH ---> K2SO4 + 2H2O
:)
Question 5 is the second one.
The lab report contains the theory, process, data and calculation of the experiment. The theory and process are remains fixed for a particular experiment. Thus there is no chance to get error from these two part. The calculation depends upon the reading or data of the experiment. The calculation is also unique and based on the data. Thus the error come from the data of the experiment. As for example for a titration experiment the data recorded in the process from the burret is the source of error, on which the calculation depends.
