Chemical Composition of the Atmosphere
Key Points
- The atmosphere is a mixture of gases that surrounds the Earth.
- The composition of the atmosphere varies with altitude.
- The major components of the atmosphere are nitrogen, oxygen, and argon.
- The atmosphere also contains trace amounts of other gases, such as carbon dioxide, methane, and water vapor.
- The atmosphere is important for life on Earth because it provides oxygen for respiration and protects the Earth from harmful solar radiation.
Main Concepts
- Nitrogen: Nitrogen is the most abundant gas in the atmosphere, making up about 78% of the total volume.
- Oxygen: Oxygen is the second most abundant gas in the atmosphere, making up about 21% of the total volume. It is essential for life on Earth because it is required for respiration.
- Argon: Argon is the third most abundant gas in the atmosphere, making up about 0.93% of the total volume. It is a noble gas, which means that it is non-reactive.
- Trace Gases: The atmosphere also contains trace amounts of other gases, such as carbon dioxide, methane, and water vapor. These gases are important for regulating the Earth's climate.
- Importance of the Atmosphere: The atmosphere is important for life on Earth because it provides oxygen for respiration and protects the Earth from harmful solar radiation.
Conclusion
The chemical composition of the atmosphere is important for life on Earth. The major components of the atmosphere are nitrogen, oxygen, and argon. The atmosphere also contains trace amounts of other gases, such as carbon dioxide, methane, and water vapor. These gases are important for regulating the Earth's climate.
Chemical Composition of the Atmosphere Experiment
Experiment Overview
This experiment demonstrates the chemical composition of the atmosphere and highlights the presence of various gases, including oxygen, carbon dioxide, and nitrogen.
Materials:
- 5 graduated cylinders
- 1 large glass container
- 1 candle
- 1 cup of water
- 1 bag of lime (calcium oxide)
- 1 pair of safety goggles
- 1 pair of gloves
Procedure:
1. Set Up the Glass Container:
- Place the large glass container on a stable surface.
- Fill the container halfway with water.
2. Light the Candle:
- Place the candle in the center of the container, making sure it is not touching the water.
- Light the candle.
3. Cover the Container:
- Carefully place the graduated cylinder upside down over the candle.
- Ensure that the cylinder is completely submerged in water, creating an airtight seal.
4. Observe and Record:
- Observe the candle as it burns. Note the color of the flame and the rate at which it burns.
- Keep track of the time it takes for the candle to extinguish.
5. Analyse the Results:
- Once the candle has extinguished, remove the graduated cylinder.
- Measure the amount of water that has entered the graduated cylinder.
- Calculate the volume of gas that was present in the container before the candle was lit.
6. Repeat the Experiment:
- Repeat the experiment using different substances in the container, such as lime (calcium oxide) or baking soda (sodium bicarbonate).
- Observe and record the results for each substance.
Key Procedures:
- Lighting the candle represents the combustion process that consumes oxygen.
- The graduated cylinder captures the gases produced during combustion.
- Measuring the water level change indicates the volume of gas present before combustion.
- The burning rate and flame color provide insights into the chemical composition of the gas.
Significance:
This experiment showcases the chemical composition of the atmosphere and demonstrates the role of oxygen in combustion. It allows students to explore the relationship between the chemical composition of gases and their reactivity. The experiment also highlights the importance of oxygen in sustaining life and its role in creating a suitable environment for various chemical reactions.