EXPERIMENT: WATER PROPERTIES

OBJECTIVES
Investigate water as a solvent.
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All life on Earth requires water. One of water's special properties is the ability to dissolve many different solutes. In fact, it is called the universal solvent. Water is necessary to dissolve and transport chemicals in living things. It is the basis for all chemical reactions for both plants and animals. Soil acts as a filter for plants, thus plants rely on water to dissolve the nutrients from the soil. The roots then transport the dissolved nutrients throughout the plant so it may grow and survive.

In this investigation you will observe what occurs after two different water mixtures are filtered and tested with phenolphthalein. Phenolphthalein, is an indicator that will turn pink in the presence of an alkaline substance with a pH of 8.2 to 10.0. Pure water, like distilled water, is neutral and has a pH of 7.0. Thus, you will be able to observe the chemicals presence in the mixture after being filtered. Given the results of your investigation you should be able to answer the questions and write a report on hydroponic gardening at the end of the experiment.


Materials:
chalk
calcium hydroxide
funnel
filter paper
phenolphthalein
three beakers
Erlenmeyer flask
stirring rod or plastic spoon
metric balance or measuring spoons
distilled water
goggles
Safety: Wear goggles when using phenolphthalein and calcium hydroxide. Wash hands thoroughly when the lab is completed. Please read through the safety sheets that came with the chemicals or MSDS.

The following video will demonstrate how phenolphthalein reacts with water and lime water. Note that it does not demonstrate safety precautions.

Read through the entire experiment before beginning your own investigation so you will be able to answer the questions and write your report in the essay box below.

Procedure:
Before the experiment put on your goggles.
Crush a half stick of classroom chalk (a mixture of limestone and gypsum) finely and place it in a beaker.
Add 50 mL of distilled water to the beaker and stir well.
To prepare your filter apparatus first fold the filter paper in half so that it looks like a semi-circle. Fold it in half again so it now has the shape of a triangle. Put it in the funnel and open one layer of the filter so that it fits along one side of the funnel. The other three layers should fit along the other side of the funnel. You may want to slightly wet the edges of the filter paper with water so that it lays flat along the sides of the funnel.
Place the funnel in the Erlenmeyer flask, and pour the mixture through it. The mixture may still appear cloudy. If you want it clearer, then filter it again using new filter paper. If not, the mixture will still work.
Place a few drops of phenolphthalein and observe.
In a beaker, mix 10 g or 1 teaspoon of calcium hydroxide with 50 mL of distilled water and stir.
Once again prepare the filter apparatus by repeating the procedure in step 3.
Place the funnel in the Erlenmeyer flask, and pour the mixture through it. The mixture may still appear cloudy. If you want it clearer, then filter it again using new filter paper. If not, the mixture will still work.
Place a few drops of phenolphthalein and observe.
Make sure you clean up and wash your hands before you answer the questions and write your report.