Inorganic Chemistry Flashcards
Group 1 alkali metals
- They form alkaline solutions when they react with water
- All soft metals
- Low densities and low melting points
- Very reactive
Metal + water
Metal hydroxide + Hydrogen
Lithium + water (observation)
Forms Lithium hydroxide + hydrogen
Observations:
- Slow reaction
- Fizzing
- Moves on surface of the water
Sodium + water (observation)
Forms Sodium hydroxide + hydrogen
Observations:
- Morre vigorous fizzing
- Moves rapidly on the surface of the water
- Dissolves quickly
Potassium + water (observation)
Forms Potassium hydroxide + hydrogen
- Burns with a lilac flame
- Moves rapidly on the surface
Group 7 Halogens
Non-metals that are poisonous
7 electrons on the outer shell
Diatomic (comes in pairs)
Displacement Reactions: (Potassium chloride)
X
Displacement Reactions:(Potassium bromide)
Chlorine Cl2: Chlorine displaces the bromide ions, Yellow-orange colour of bromine seen
Bromine BR2: X
Iodine I2: No reaction
Displacement Reactions: (Potassium Iodide)
Chlorine Cl2: Chlorine displaces the iodide ions, Brown colour of iodine is seen
Bromine Br2: Bromine displaces the iodide ions, Brown colour of iodine is seen
Iodine I2: X
Group 7 reactivity & electronic configurations
When halogen atoms gain an electron during reactions, they form -1 ions called hallide ions.
Reactivity of Group 7 non-metals decreases as you go down the group
However, halogen atoms form negative ions when they gain an electron to obtain a full outershell meaning the further away from the nucleus, the less reactive it becomes.
Composition of Air
78% Nitrogen
20.9% Oxygen
0.09% Argon
0.04% CO2
How do we find the percentage of oxygen in air?
Use a non-metal or metal by reacting with the oxygen in a fixed volume of air.
Burn a small amount of phosphorus in a bell jar that sitting in a trough of water
As phosphorus is getting burnt, it uses up the oxygen inside the bell jar and the water level rises. Make careful measurements of water levels before and after to calculate the percentage of oxygen in air.
Experiment: Determine the % of Oxygen in Air
?
Combustion
Scientific word for burning
Must involve oxygen
It’s an exothermic reaction
Magnesium observation during combustion
Intense white flame
White powder produced (magnesium produced)
Hydrogen observation during combustion
Exothermic, water is produced
Sulfur observation during combustion
Blue flame, colourless, poisonous gas produced
Carbon Dioxide from Thermal Decomposition
It is when a substance breaks down due to the action of heat
E.g Metal carbonate -> metal oxide + carbon dioxide
Text for carbon dioxide is lime water
The Greenhouse Effect
It maintains the temperatures on Earth high enough to support life.
Three greenhouse gases:
- Methane
- CO2
- Water vapour
Steps: Sun’s rays enter Earth -> Energy is absorbed by the Earth’s surface and re-emitted at longer wavelengths, such as infrared radiation (heat), Some emitted heat passes through the atmosphere into space -> Some heat is absorbed by greenhouse gases and are stored
