Emergent Properties of Water - Lab Report

Categories: Chemistry

Report, Pages 6 (1384 words)

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Abstract:

This lab report explores the emergent properties of water, including adhesion, cohesion, polarity, temperature stabilization, solvency, and density changes. Various experiments were conducted to investigate these properties, and the results demonstrate the unique characteristics of water that make it essential for life.

Introduction:

Water is a fundamental molecule for life on Earth, and its emergent properties play a crucial role in the functioning of living organisms. In this lab, we conducted experiments to examine and confirm these emergent properties.

Methods:

We conducted several experiments to investigate the emergent properties of water:

1. Adhesion and Cohesion:

In the first experiment, we observed adhesion and cohesion by placing water droplets on glass and wax paper surfaces. We noted that the water droplet on the glass spread out, while the one on the wax paper maintained its droplet form. This phenomenon is due to the adhesive properties of water, where water molecules stick to the glass molecules, preventing the droplet from falling when the glass is inverted.

Water's polarity, with a slightly positive and slightly negative side, results in attractive forces between water and glass.

2. Cohesion in Plants:

We also observed cohesion in plants during the experiment. Water droplets on a wax paper surface maintained their shape due to water's high cohesion. Water molecules are attracted to each other because of their charges, and this property is essential in processes like transpiration, where water is pulled up through a plant's vascular system.

3. Polarity:

To confirm water's polarity, we dipped one end of a toothpick into a petri dish of water with pepper.

The pepper moved away from the toothpick, indicating that water is polar. Water's polarity arises from its unequal electron sharing and molecular shape, making it attract other polar molecules while repelling non-polar ones.

4. Temperature Stabilization and Density:

We investigated temperature stabilization and density by placing an ice cube in a beaker of room temperature water. The water's temperature decreased as the ice cube melted, illustrating how water absorbs heat to reach thermal equilibrium. The ice floated because it is less dense than liquid water, a property crucial for the survival of aquatic life during winter when ice forms on the surface.

5. Solvency:

Lastly, we explored water's solvency by dissolving salt in water. The negatively charged oxygen molecules in water were attracted to sodium cations, while the positively charged hydrogen atoms were attracted to chlorine anions, leading to the dissolution of salt. Water's ability to dissolve various substances is essential for biological processes.

Results and Discussion:

Our experiments confirmed the emergent properties of water, including adhesion, cohesion, polarity, temperature stabilization, density changes, and solvency. These properties are critical for the survival of living organisms and the functioning of biological systems.

Water's unique properties, such as adhesion and cohesion, enable it to move nutrients through plants and maintain the integrity of cellular structures. Its polarity allows it to form bonds with other substances, facilitating chemical reactions essential for life. Water's role in temperature regulation and its ability to dissolve various compounds make it the "solvent of life."

Conclusion:

In conclusion, after conducting the lab, the emergent properties of water were tested and proved. These trials and experiments were able to verify the adhesion, cohesion, polarity, temperature stabilization, solvency, and density changes exhibited by water. During the glass and wax paper lab, we observed the adhesive properties of water. When a droplet of water touched the glass, it dispersed immediately.

The droplet placed on the wax paper remained intact and in droplet form. Also, when the glass and wax sheets were flipped, the water remained on the glass and fell off the wax paper. This is due to adhesion; the water molecules stuck to the glass molecules and prevented the droplet from falling when the glass was turned upside down. Water is polar. Its electrons are unevenly distributed among the molecule with two unshared electron pairs on the oxygen atom. The hydrogen atoms align themselves along one side of the oxygen atom, causing a slightly positive and slightly negative side.

This causes a dipole to occur. Since glass is also polar, the water and the glass will be attracted to each other because of their positive and negative charges. In real life, adhesive properties are vital for the survival of plants. Water molecules will adhere themselves to cellular membranes of plants and move up the plant to provide nutrients. Without adhesion, all the water will remain in the ground as gravity pulls down on it. In addition to adhesion, water molecules can also exhibit cohesion. As referenced in the paragraph above, when the water droplet touched the wax paper, the water did not disperse. Instead, it remained in its droplet form.

This is because water is highly cohesive; it is attracted to itself. The reason it stays in droplet form is because the positively charged hydrogen atoms are attracted to the negatively charged oxygen atoms. Therefore, when you have to water molecules, they will instantly be attracted to each other because of the charges. Since wax is non-polar and hydrophobic, the water molecules did not react with the wax paper and remained attracted to itself. Cohesion can also be observed in plants.

Transpiration is the evaporation of water through a plant. As the water evaporates, it pulls the water at the roots up and with cohesion, more water is pulled up as well. Water is also polar. Its polarity was tested when one end of a toothpick was touched into a petri dish of water with pepper. It was immediately observed that the end of the toothpick repelled the water because the pepper was pushed towards the sides of the dish.

Since the substance at the end of the toothpick was determined to be non-polar and hydrophobic, water must be polar. The molecules of water are not attracted to the uncharged molecules of the substance on the toothpick and is repelled by it. Molecularly speaking, the water molecule contains two hydrogen atoms joined by a single oxygen atom with covalent bonds. Oxygen is more electronegative than hydrogen and due to the unequal electron sharing and the water molecule’s shape, the overall charge is unevenly distributed.

The polarity of water helps it to form bonds with itself and other substances which is helpful in the survival of many living organisms. Water is also useful for temperature stabilization. In one of the experiments, an ice cube was dropped into a beaker of water at room temperature. The temperature of the water grew cooler and the ice cube was getting smaller. Also, the ice was floating. All of these observed properties can be summarized as temperature regulation and density.

Whenever two objects of different temperatures are mixed together, the cooler object is always absorbing heat from the warmer one until the two objects are the same temperature. When a glass of warm water is placed into a room, it will eventually cool down to room temperature. The same thing is occurring as the ice cube settles in the beaker of water. Molecules of the cooler object speed up to match the kinetic energy of the warmer object. As this is all happening, the heat the ice is absorbing will also melt it, which explains why the ice cube is getting smaller.

The ice is floating because it is less dense than water; solidified water molecules are farther apart than liquid water because the hydrogen bonds keep the molecules apart. During the winter, lakes, ponds, and rivers do not freeze all the way to the bottom. The ice that forms floats on the top, allowing liquid water to run underneath for marine life to survive during the harsh conditions of winter. The last important emergent property of water is its ability to be used as the “solvent of life.” When the salt was placed into the water, it began dissolving immediately.

The salt dissolved because the oxygen molecules of the water were negatively charged and attracted to the sodium cations. Also, the positively charged hydrogen atoms were attracted to the chlorine anions. This attracted resulted in the formation of hydration shells in which the water molecules dissolved each ion. There are many different substances and compounds being dissolved in water daily. Some examples are blood, the liquid within cells, and in food or cooking. Water is truly the solvent of life.