Question 1: Carbon Dioxide (CO₂) is a colorless, odorless gas produced during respiration and combustion. It is also used in industry and in carbonated beverages. Understanding its properties helps us identify and utilize it effectively.

Answer: Carbon Dioxide is a colorless, odorless gas produced during respiration and combustion, used in industry and carbonated drinks, identifiable by specific tests.

Question 1: Describe two physical properties of Carbon Dioxide that differentiate it from oxygen.

Answer: Carbon Dioxide is denser than air and is colorless and odorless.

Question 2: Explain the principle behind the limewater test for Carbon Dioxide.

Answer: When CO₂ is bubbled through limewater, it reacts with calcium hydroxide to form calcium carbonate, turning the limewater milky.

Question 1: What is the chemical reaction involved in the limewater test for Carbon Dioxide?

Answer: CO₂ + Ca(OH)₂ → CaCO₃ (s) + H₂O

Question 2: Which other gases do not produce a milky limewater when tested, and why?

Answer: Oxygen and nitrogen do not react with limewater, so they do not turn it milky because they do not form insoluble calcium carbonate.

Question 1: Describe a safe method to collect and test Carbon Dioxide in a school laboratory setting.

Answer: Use a delivery tube to collect CO₂ over water or in a gas syringe, ensure proper ventilation, and wear safety goggles and gloves during handling.

Question 2: Identify two variables that need to be controlled during the limewater test for accurate results.

Answer: The amount of limewater used and the duration of bubbling CO₂ through limewater.

Question 1: In an experiment, a student bubbles unknown gas through limewater, and it turns milky. What conclusion can they draw about the gas, and what evidence supports this?

Answer: The gas is Carbon Dioxide because it reacts with limewater to form calcium carbonate, causing the milky appearance.

Question 1: Explain how Carbon Dioxide is used in the food industry, particularly in carbonated beverages.

Answer: CO₂ is dissolved under pressure into beverages to create bubbles, giving carbonated drinks their fizz and texture.

Question 2: Discuss the environmental impact of increased Carbon Dioxide emissions from human activities.

Answer: Increased CO₂ emissions contribute to global warming and climate change by trapping heat in the atmosphere, leading to rising temperatures, melting ice caps, and changing weather patterns.