Question

Material balance. If you intend to measure all the anions and cations in an unknown, one sanity check on your results is that the total positive charge should equal the total negative charge. The table lists concentrations of anions and cations measured in pond water in an undergraduate experiment and expressed in mg/mL.

Find the total concentration of negative and positive charge (mol/L) to assess the quality of the analysis. What do you conclude about this analysis?

Short answer

The total concentration of negative and positive charge (mol/L) is as follows:

Total cation charge: 0.00202M

Total anion charge: -0.00159M

Step-by-step solution

Calculate the concentration by using equation:

$$\begin{gathered} c(species;mol/L)=-\frac{valuefromspreadsheet}{molar-mass¯(of)anion/cation}\times {10}^{-6}/{10}^{-3} \\ c(totalconcentration)=\sum (species;mol/L) \end{gathered}$$

Calculation of values

From the above equation we conclude that

Total cation charge: 0.00202M

Total anion charge: -0.00159M

Analysis

From this we can conclude that some concentrations can be inaccurate, or some ionic species were not detected.