Question 1: Define oxygen and describe its role in combustion.

Answer: Oxygen is a colorless, odorless gas that supports combustion by reacting with combustible materials, producing heat and light.

Question 2: Explain the principle behind testing for oxygen using a glowing splint.

Answer: A glowing splint relights in the presence of oxygen because oxygen supports combustion, causing the splint to reignite.

Question 1: Calculate the volume of oxygen gas (in liters) at standard temperature and pressure (STP) when 16 grams of oxygen are collected. (Molar mass of O2 = 32 g/mol)

Answer: 11.2 liters

Question 2: If 5 liters of pure oxygen are produced in a reaction, how many moles of oxygen are present? (Use 22.4 L/mol at STP)

Answer: 0.223 moles

Question 1: Describe the key variables that need to be controlled when testing for oxygen with a glowing splint in a laboratory setting.

Answer: Variables include the concentration of oxygen, the temperature, the size and glow of the splint, and ensuring no other gases interfere with the test.

Question 2: List three safety precautions that should be followed during experiments involving oxygen gas.

Answer: Use proper ventilation, avoid open flames near oxygen, and handle gas cylinders with appropriate equipment to prevent leaks and accidents.

Question 1: A student collects 20 liters of gas produced during a reaction. Upon testing with a glowing splint, the splint relights. What can be inferred about the gas, and what steps would you take to confirm its identity?

Answer: The gas is likely oxygen because it supports combustion. To confirm, perform additional tests such as reacting it with a burning splint or analyzing its reactivity with other substances.

Question 1: Explain how the glowing splint test works for detecting oxygen and discuss any limitations of this method.

Answer: The glowing splint test works because oxygen supports combustion, causing the splint to relight. Limitations include false positives if other reactive gases are present, and it cannot quantify oxygen levels or detect oxygen in mixtures without further tests.

Question 1: Describe two industrial applications of oxygen and explain why oxygen is essential in these processes.

Answer: Oxygen is used in steelmaking to remove impurities and in medical oxygen therapy to support patients' breathing. It is essential for oxidation reactions and supporting combustion in these industries.

Question 2: How might advances in oxygen technology benefit environmental protection efforts?

Answer: Advances such as oxygen-enriched combustion can improve fuel efficiency and reduce emissions, helping to decrease air pollution and greenhouse gases.