An Experiment to Determine the Total Hardness of 4 Different Types of Bottled Water

Discussion

This graph shows the comparison between the manufacturer’s claims of the concentration of calcium ions in mg/L in their water verses the results that our group has gotten from titrating their water samples.

Similarly to the graph above, this graph shows the comparison between the manufacturer’s claims of the concentration of magnesium ions in mg/L in their water verses the results that our group has gotten from titrating their water samples.

From both graphs, it can be seen from the trend line that the titration results of calcium and magnesium ions in the water is greater than the manufacturer’s claims. Both trend lines are growing exponentially and the trend line for the titration results are greater than the trend line of the manufacturer’s claims, which demonstrates that their claims may not be as accurate as they seem.

For Thank You Water, Evian Water and Tap water, the results of both calcium and magnesium ions in the water samples is noticeably larger than what the manufacturer declares that there is to be. The manufacturer’s claim for Pureau Pure Water was 0mg/L for both calcium and magnesium, and from the experiment results, the claim turned out to be true.

It can also be observed that the concentration of both calcium and magnesium ions in Australian Natural Spring Water is double the amount of what the manufacturer claims that there is. The manufactures of Australian Natural Spring Water states that there is 3mg/L of both calcium and magnesium ions in their bottled water, however, the results say that there are 6mg/L of both calcium and magnesium ions in their bottled water.

(Clean and Green Products, n.d.)

From the titration results, the average total hardness of the bottled water is 42.25mg...

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... concluded that tap water was harder than bottled water.

Recommendations for future experiments that are similar to this experiment is to minimize all sources of error where possible, such as using a smaller bottle with a smaller tip for the Erichrome Black-T indicator, and having more conical flasks around to avoid reusing flasks. To get more accurate results, it is also recommended to test with a larger range of bottled water, and different sources of Brisbane tap water, and to test with more trials.

Reference List

University of Canterbury. (n.d.). Total Calcium and Magnesium Ion Concentration. Retrieved May 29, 2014, from http://www.outreach.canterbury.ac.nz/chemistry/calcium_magnesium.shtml

Water Hardness in Australia. (n.d.). Clean & Green. Retrieved May 28, 2014, from

http://www.cleanandgreenproducts.com.au/Water-Hardness-in-Australia-pg21462.html