Gas Chemistry Flashcards
Uses of Carbon Dioxide
• In fire extinguishers
• In fizzy drinks
Gas Collection
• Upward delivery for gases less dense than air
• Downward displacement for gases denser than air
Test for Carbon Dioxide
• Bubble gas through limewater - turns milky
• If excess COz is added, the milky precipitate dissolves
Chemical Properties of Carbon Dioxide
• Reacts with water to form weak carbonic acid
• Reacts with alkalis to form a salt and water
Carbon Dioxide
• Colourless, odourless gas
• Low solubility in water
• More dense than air
Preparation of Carbon Dioxide
Reaction of calcium carbonate with dilute hydrochloric acid
Chemical Properties of Oxygen
• Supports combustion
• Reacts with metals to form solid basic oxides
• Reacts with non-metals to form gaseous acidic oxides
Test for Oxygen
Apply a glowing splint - it relights
Uses of Oxygen
• In medicine
• In welding
Oxygen
• Colourless, odourless gas
• Slightly soluble in water
• Slightly more dense than air
Preparation of Oxygen
Decomposition of hydrogen peroxide using manganese(IV) oxide catalyst
Uses of Manganese(IV) oxide
Manganese(IV) oxide is used as a catalyst to speed up the
decomposition of hydrogen peroxide
Hydrogen as a clean fuel
• Produces only water when burned
• But manufacturing hydrogen may use electricity from fossil fuels
Dangers of hydrogen
Hydrogen is extremely flammable so : leaks could lead to an explosion, requiring high level safety controls
Preparation of Hydrogen
Reaction of dilute hydrochloric acid with a metal
Physical Properties of Hydrogen
• Colourless, odourless gas
• Insoluble in water
• Less dense than air
Uses of Hydrogen
• Meteorological balloons
• Hardening oils to make solid fats
• Potential as a clean fuel
Uses of Ammonia
• Reacts with acids to produce ammonium salts used as artificial
fertilisers
Hydrogen
• First element in the Periodic Table
• Exists as a diatomic molecule
• Occurs in water, oil, natural gas and all living things
Test for Ammonia
• Dip glass rod in concentrated hydrochloric acid and hold close to the gas
• White smoke of ammonium chloride is formed if ammonia is
present
Uses of Nitrogen
• Liquid nitrogen used as a coolant
• Inert atmosphere in food packaging
Ammonia (NH3)
• Colourless gas with pungent smell
• Very soluble in water forming an alkaline solution
Physical Properties of Nitrogen
• Colourless, odourless gas
• Insoluble in water
• Extremely unreactive
• Exists as a diatomic molecule
Why is nitrogen unreactive?
Nitrogen is unreactive due to the strong triple covalent bond between the two nitrogen atoms which requires substantial energy to break before the nitrogen atoms can react
Composition of Air
• Nitrogen
• Water vapour
• Oxygen
• Noble gases & Argon
• CO2
Nitrogen
• Most abundant constituent of the atmosphere
• Present in all living matter
• Essential part of all plant and animal life
Air
Mixture of gases that makes up the Earth’s atmosphere and is essential for life
