space.template.3.Lab6WaterSoftening

=Water Softening=

Objective: Determine the most effective way to soften hard water.

In previous labs you have learned that the water that we use on a daily basis, is not just molecules of hydrogen and oxygen. Many things can dissolve in and contaminate our water. Our water treatment plants are here to provide water that is safe to drink, but doesn't necessarily produce pure water. In the water testing lab, you examine several samples of bottled water, as well as the schools water to investigate if ions were present in the water. Two groups identify the schools water as having calcium ions present. The presence of these ions in moderation is not a bad thing, but does indicate that the schools water is what we would consider hard water. Hard water is water that contains and excess of Calcium, Iron, and Magnesium ions.

The objective of the following investigation is to examine several ways of softening water by comparing three possible water treatments and determining whether they remove calcium ions from a hard-water sample: (1) sand filtration, (2) treatment with Calgon, and (3) treatment with an ion-exchange resin. The effects of calgon on the calcium in the hard water are that it should react with the sodium hexametaphosphate forcing it to become part of a larger more soluble anions, keeping it from forming insoluble compounds. The ion exchange resin works to remove the calcium by trapping it in porous beads, thus removing it from the water.

Two laboratory tests will help you decide whether your original hard-water sample has been softened. The first test is the reaction between hard-water calcium cations and carbonate anions (added as sodium carbonate, Na2CO3, solution) to form a calcium carbonate precipitate. If calcium cannot be detected, then there will be no precipitate. The second test is to observe the effect of adding soap to the water sample, forming a lather. Hard water does not form a lather.

Before starting, learn what you will need to do, note safety precautions, and plan necessary data collecting and observations.

Prelab - must be answered in background information of formal lab report
1.) What is the objective of the lab? 2.) What is hard water? 3.) What ion will you be trying to remove from the hard water sample in this lab experiment? 4.) ) How does Calgon work to treat hard water; How does the ion exchange resin work to treat hard water? 5.) Hypothesis: Which methods do you predict will work to remove the calcium from the water.

Procedure
Describe the steps that you followed to complete this procedure.

Data
Create a data table showing your results

Analysis
1.) What are the two positive results for calcium in the water? 2.) Which samples contained calcium and can be classified as hard water still? 3.) If you were in charge of recommending a method of water softening to Killingly High School, which would you recommend and why? (3 parts - see below) a.) What was the most effective method in lab? b) Using the internet and other resources, determine what the most cost effective way is to remove the ions from water? c.) Describe how you would make your filter

Conclusion
What did you observe from your data? Be specific, give examples! How confident are you in your results? Could any errors have occurred; if so, how would you fix them? What might you change about this experiment, should you investigate it further?