Question

Demonstrate that exhale air contains carbon dioxide

Answer 1

Answer:

Respiration by living organisms can be investigated by carrying out experiments to show the production of carbon dioxide and heat.

Limewater can be used to detect carbon dioxide.If carbon dioxide is bubbled through limewater then it turns from clear to cloudy/milky in colour. This is why limewater used in a simple respirometer can show that more carbon dioxide is present in exhaled air compared to inhaled air.

Breathing in through the mouthpiece draws air from the atmosphere in through tube A. Breathing out through the mouthpiece bubbles exhaled air through tube B. After a few breaths the limewater in tube B will turn cloudy as the exhaled air contains more carbon dioxide.