do now! can you read through the notes we made last lesson?
TRANSCRIPT
Do now!Can you read
through the notes we made last
lesson?
Last lesson
• Reactions of sulphur dioxide in water and with alkalis
• Laboratory production of carbon dioxide
• Reactions of carbon dioxide in water and with alkalis
Sulphur dioxide SO2
Produced by burning sulphur (or burning fossil fuels)
S(l) + O2(g) SO2(g)
In water
Dissolves to form sulphurous acid
SO2(g) + H2O(l) H2SO3(aq)
With an alkali
Forms a sulphite
SO2 + 2NaOH Na2SO3 + H2O
Carbon dioxide
Preparing carbon dioxide
Acid + carbonate salt + water + carbon dioxide
2HCl + CaCO3 CaCl2 + H2O + CO2
In water
Dissolves to form carbonic acid
CO2(g) + H2O (l) H2CO 3(aq)
pH 5.5
In alkali
H2CO 3(aq) + 2NaOH(aq) Na2CO3(aq) + 2H2O(l)
acid + base salt + water
Today’s lesson
• Uses of carbon dioxide
• Oxides of nitrogen
Uses of carbon dioxide
Fizzy drinks. The higher the pressure, the more soluble the gas becomes.
So what happens when the pressure
is released?
Uses of carbon dioxide
Dry ice (actually it’s condensed water vapour that you can see.)
Uses of carbon dioxide
Fire extinguishersHow does it
work?
Oxides of nitrogen
Nitrogen is generally an unreactive gas, and needs fairly extreme conditions to get it to react with oxygen
Nitric oxide, NO
Lightning brings about the direct union of nitrogen and oxygen in the air to produce small amounts of nitric oxide, as does the high temperatures produced in car engines.
Nitric oxide, NO
It is a toxic air pollutant, often linked with asthma and allergic responses
Nitrous oxide, N2O
Formed when ammonium nitrate, NH4NO3, is heated. A colourless gas with a pleasing odour and sweet taste, is used as an anesthetic for minor operations, especially in dentistry.
Nitrous oxide, N2O
It is called laughing gas because of its intoxicating effect. It is alsowidely used as a propellant in aerosol cans of whipped cream!
Nitrogen dioxide, NO2
In the presence of excess oxygen, nitric oxide, NO, will be converted to nitrogen dioxide,NO2. Nitrogen Dioxide is a reddish brown, toxic gas at room temperature. NO2 condenses to a brown liquid, but freezes to a colourless solid.
Nitrogen dioxide, NO2
Nitrogen Dioxide has been used as a catalyst in certain oxidation reactions; as a nitrating agent for organic compounds; as an oxidizing agent; as a rocket fuel; and as a flour bleaching agent
Stick them in
Can you stick the slides in your books?
Fractional distillation of air
Can you carefully read through the sheet. Then condense it to 4 sentences of no more than 12 words a sentence.