state the chemical reagent that is used to demonstrate that expired air contains carbon dioxide
It is proven by the colour of the limewater that CO2 is present in the expired/exhaled air after air is blown in the beaker
Yes ,I agree with Pathneythe lime water will turn milky with the presence of the expired air
Carbondioxide
And the chemical reaction for the expirement showing how expired air contains carbon dioxide is
Ca(0H)2+Co2-CaCo3+H20
To demonstrate that expired air contains carbon dioxide, you can use a chemical reagent called limewater (aka calcium hydroxide solution). Here's how you can carry out the experiment:
Materials:
- Limewater (calcium hydroxide solution)
- Straw or a tube
- Balloon
- Source of expired air (your mouth)
Procedure:
1. Prepare the limewater solution by mixing calcium hydroxide (available as a solid or powder) with water to form a saturated solution. Ensure the solution is clear without any undissolved solids.
2. Pour the limewater solution into a clear container, such as a flask or a glass.
3. Attach a straw or a tube to the opening of a balloon.
4. Gently blow into the balloon, ensuring that the expelled air passes through the straw or tube.
5. Direct the other end of the straw or tube into the limewater solution, allowing the expelled air to bubble through the solution.
Observation:
6. Observe the changes taking place in the limewater. If carbon dioxide is present in the expired air, it will react with the limewater to form a milky or cloudy precipitate of calcium carbonate (a white solid).
Explanation:
The limewater reacts with carbon dioxide (CO2) gas, present in expired air, to form calcium carbonate (CaCO3), a white solid. The chemical reaction can be represented as follows:
CO2 (g) + Ca(OH)2 (aq) → CaCO3 (s) + H2O (l)
By observing the formation of the milky precipitate in the limewater, you can conclude that expired air contains carbon dioxide.
Note: It is essential to handle chemicals with care and carry out the experiment in a well-ventilated area. If conducting this experiment in a laboratory or classroom setting, it is recommended to follow safety protocols and guidelines.