8.2 Identification of common gases

• Hydrogen gas produces a squeaky pop sound when lit
• Chlorine gas bleaches damp litmus paper
• Oxygen is a colorless and odorless gas that supports combustion.


  True
• Hydrogen is a colorless and odorless gas.


  True
• Order the chemical tests for identifying common gases based on their observations:

  1️⃣ Hydrogen: Squeaky pop sound when lit

  2️⃣ Oxygen: Relights a glowing splint

  3️⃣ Carbon dioxide: Forms a white precipitate with limewater

  4️⃣ Chlorine: Bleaches damp litmus paper

  5️⃣ Ammonia: Turns damp red litmus paper blue
• Chlorine gas turns damp litmus paper blue.

  False
• Arrange the following gases in alphabetical order:

  1️⃣ Ammonia

  2️⃣ Carbon dioxide

  3️⃣ Chlorine

  4️⃣ Hydrogen

  5️⃣ Oxygen
• Match the gas with its identifying test:

  Oxygen ↔️ Relights a glowing splint

  Hydrogen ↔️ Produces a squeaky pop sound

  Chlorine ↔️ Bleaches damp litmus paper

  Ammonia ↔️ Turns damp red litmus paper blue
• What is the density of carbon dioxide relative to air?

  Denser than air
• What happens to damp litmus paper when exposed to chlorine gas?

  It bleaches
• What is the physical property of chlorine that helps identify it?

  Pungent odor
• Oxygen gas relights a glowing splint.

  True
• Ammonia gas turns damp red litmus paper blue.


  True
• Carbon dioxide is a colorless, odorless gas that is denser than air
• What is the density of carbon dioxide relative to air?

  Denser than air
• What happens when a glowing splint is brought to oxygen gas?

  Relights the glowing splint
• What sound is produced when hydrogen gas is ignited with a lit splint?

  Squeaky pop sound
• Which gas is the lightest of all gases?

  Hydrogen
• It is safe to handle toxic gases without personal protective equipment in a well-ventilated area.

  False
• Oxygen relights a glowing splint
• Ammonia turns damp red litmus paper blue
• Match the gas with its chemical test observation:

  Hydrogen ↔️ Squeaky pop sound

  Oxygen ↔️ Relights a glowing splint

  Carbon dioxide ↔️ Forms a white precipitate

  Chlorine ↔️ Bleaches damp litmus paper
• When handling gases, it is crucial to be aware of their physical properties
• Carbon dioxide forms a white precipitate when bubbled through limewater.
• Hydrogen is the lightest of all gases
• Which gases mentioned in the study material are toxic or corrosive?

  Chlorine and ammonia
• Steps to identify an unknown gas in a chemistry lab

  1️⃣ Observe its physical properties

  2️⃣ Perform relevant chemical tests

  3️⃣ Confirm its identity
• Working in a well-ventilated area reduces the risk of hazardous gas buildup.


  True
• Oxygen relights a glowing splint.

  True
• Ammonia turns damp red litmus paper blue.


  True
• Wearing safety goggles is essential when identifying gases in a chemistry lab.


  True
• Adhering to safety guidelines protects both yourself and others in the lab.


  True
• What type of PPE should you wear when working with common gases in a lab?

  Safety goggles, gloves, lab coat
• What are the common gases that can be identified in a chemistry lab?

  Hydrogen, oxygen, carbon dioxide, chlorine, ammonia
• What does carbon dioxide form when bubbled through limewater?

  White precipitate
• Which gas is the lightest of all gases?

  Hydrogen
• What is the color and odor of chlorine gas?

  Greenish-yellow, pungent
• Hydrogen is the lightest of all gases
• Carbon dioxide bubbled through limewater forms a white precipitate
• What happens to damp red litmus paper when exposed to ammonia gas?

  Turns the litmus paper blue