College

# Experiment: Water Properties

## Objectives
- Investigate water as a solvent.

**Introduction:**

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 present 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.

**Note:**

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

**Instructions:**

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

## Procedure:

1. **Preparation:**
- Put on your goggles.

2. **First Mixture:**
- 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.

3. **Filter Apparatus Preparation:**
- 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.

4. **Filtering First Mixture:**
- Place the funnel in the Erlenmeyer flask, and pour the mixture through it. The mixture may still appear cloudy. If you want it clearer, filter it again using new filter paper. If not, the mixture will still work.
- Place a few drops of phenolphthalein and observe.

5. **Second Mixture:**
- In a beaker, mix 10 g or 1 teaspoon of calcium hydroxide with 50 mL of distilled water and stir.

6. **Filtering Second Mixture:**
- 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, filter it again using new filter paper. If not, the mixture will still work.
- Place a few drops of phenolphthalein and observe.

7. **Cleanup:**
- Make sure you clean up and wash your hands before you answer the questions and write your report.

Answer :

The investigation aims to observe the ability of water as a solvent by testing two different water mixtures with phenolphthalein.

The objective of this experiment is to investigate water as a solvent and its ability to dissolve various solutes. Water is known as the universal solvent because it can dissolve a wide range of substances, making it essential for chemical reactions in both plants and animals. In this investigation, two different water mixtures will be tested with phenolphthalein, an indicator that turns pink in the presence of an alkaline substance with a pH of 8.2 to 10.0.

The procedure begins by preparing two different mixtures. First, crushed classroom chalk, which contains limestone and gypsum, is mixed with distilled water. The resulting mixture is filtered using filter paper to remove any solid particles. Phenolphthalein is added to observe any alkaline substances present in the mixture.

Next, a mixture of calcium hydroxide and distilled water is prepared, and the same filtration and phenolphthalein test are conducted.

Throughout the experiment, safety precautions, such as wearing goggles, handling phenolphthalein and calcium hydroxide carefully, and washing hands thoroughly after the lab, are followed to ensure safety.

The results of the investigation will be used to understand the properties of water as a solvent and its significance in hydroponic gardening, where plants rely on water to dissolve nutrients from the soil and transport them throughout the plant for growth and survival.

To learn more about water as a solvent, here

https://brainly.com/question/7932885

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Final answer:

The student's experiment highlights water's role as a universal solvent by using phenolphthalein to test the pH of water mixtures with chalk and calcium hydroxide, showcasing implications for hydroponic gardening and the purity of water.

Explanation:

Water as a Solvent and pH Testing

Water's unique properties make it an excellent solvent for many substances, which is why it is often referred to as the 'universal solvent'. The solubility of substances in water can lead to variations in water's pH, a measure of the concentration of hydrogen ions (H+) and hydroxide ions (OH-), which indicates its acidity or alkalinity. In the context of this experiment, the student is tasked to investigate water's solubility properties by observing the reaction between water mixtures and phenolphthalein, an indicator that changes color in alkaline environments. By comparing the ability of water to dissolve chalk, which primarily contains calcium carbonate, and calcium hydroxide, students can explore the chemical interactions in an aqueous environment that are crucial for hydroponic gardening. The experiment also involves testing the pH of resulting solutions by using phenolphthalein and exploring the implications of water solubility in agriculture and environmental sciences.

The steps in the experiment include dissolving substances in distilled water, filtering the solution, and adding an indicator to observe the pH changes. The observation of color changes after adding phenolphthalein to water solutions containing different solutes allows students to draw conclusions about the presence of alkaline substances and the purity of water. Furthermore, this practical application demonstrates how hydroponic gardening relies on the unique qualities of water to support plant growth.