Instructions

- Submit an initial stock solution concentration (C
_{i}), the final volume (V_{f} of the diluted solutions, and the concentration increment between the diluted solutions.

What is computed?

- The tool calculates the volume (V
_{initial}) to be taken from a stock solution of known concentration (C_{initial}) as well as the concentration (C_{final}) and dilution factor (n) of each of the diluted solutions to be prepared.
- Volume is an extensive (mass-dependent) property that can be affected by temperature changes when solutes and solvents are mixed, resulting in additional volume changes. However, for diluted aqueous solutions prepared at rutinary lab conditions (e.g. 1 atm, 25
^{o} Celsius), these additional changes are negiglible.

V_{final} = V_{initial} + V_{added} +/- V_{due to thermal changes}

V_{final} = V_{initial} + V_{added}

Because before and after dilution the number of moles of solute are the same, we can write

C_{initial}V_{initial} = C_{final}V_{final}

Therefore, a dilution factor, n, can be expressed in terms of concentrations or volumes, like this

n = C_{initial}/C_{final}

n = V_{final}/V_{initial}

n = (V_{initial} + V_{added})/V_{initial}

Who can use this tool?

- Lab techs as well as chemistry teachers and their students.

Suggested Exercises

- A chemistry lab class consists of 10 group of students. Each group needs 75.0 mL of 2 M HCl. If you are the lab tech, how would you prepare the desired amount of 2 M HCl for the entire class using a 12 M HCl stock solution?
- How would you prepare three 100-mL solutions with dilution factors of 100, 50, and 10 from an 18 M sulfuric acid solution?
- A stock solution is prepared by placing 10.0 grams of aluminum nitrate into a volumetric flask. The aluminum nitrate is then dissolved in water such that the final volume is 250.00 mL. What is the molar concentration of aluminum nitrate? How would you prepare 250.00 mL, five-fold diluted solution from the stock solution?

References

- Freiser, H. (1992). Concepts & Calculations in Analytical Chemistry: A Spreadsheet Approach. Chapter 1. CRC Press, Boca Raton.

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