Gas Chemistry Flashcards
What are the percentages of each gas in the air.
Nitrogen 78%
Oxygen 21%
Carbon dioxide 0.03-0.04%
Argon 1%
Water vapour varying proportions
Draw the diagram of nitrogen.
Describe its bond.
(Check notes)
Strong triple covalent bond in the diatomic molecule, requires a lot of energy to break (unreactive)
What are the physical properties of nitrogen?
Colourless, odourless gas.
Neutral.
Insoluble in water.
What are the uses for nitrogen?
Coolant-fast freezing
Food packaging
Draw a diagram of ammonia.
What is its formula?
(Check notes)
Double covalent bonds with 3 hydrogen atoms
NH3
How does the ammonia fountain experiment work?
Draw a diagram for the apparatus.
When water is injected into the flask ammonia dissolves and this reduces the pressure inside the flask dramatically. The water from the trough then rushes up to replace the gas.
(Check notes)
Should contain:
Jet
Dry gas
Flask with bung
Clamp
Water in syringe
Trough containing water and indicator
Atmospheric pressure arrows
How do you test for ammonia?
React with hydrogen chloride gas
HCL(g) NH3(g) -> NH4Cl(s)
What is the precipitate colour for a positive result when hydroxide ions in an ammonia solution (NH4OH) react with the following metal ions:
Mg2+
Cu2+
Al3+
Fe2+
Fe3+
Zn2+
Are they soluble in excess NH4OH?
White Mg(OH)2 (No)
Pale blue Cu(OH)2 (Yes dark blue solution)
White Al(OH)3 (No)
Green Fe(OH)2 (No)
Red-brown Fe(OH)3 (No)
White Zn(OH)2 (Yes colourless solution)
What are the physical properties of ammonia?
Colourless gas
Pungent smell
Less dense than air
Very soluble in water
Weak alkali
Draw the structure of hydrogen
Two atoms each with one electron covalently bonded.
(Remember dots and crosses, don’t be tempted to scribble it down and forget those)
What are the physical properties of hydrogen?
Colourless, odourless gas
Less dense than air
Insoluble in water
Neutral
