Today’s lesson The allotropes of sulphur Manufacture of sulphuric acid by the contact process

Can you stick the sheet in and read the instructions? Stick it in! Can you stick the sheet in and read the instructions?

Question Can you answer the question please?

Allotropes of sulphur Sulphur molecule consists of 8 atoms in a ring form.

Allotropes of sulphur It melts at 115°C (low) which is because of its simple molecular structure.

Allotropes of sulphur As it is heated more strongly, the rings break and join together to make long chains. It becomes sticky.

Allotropes of sulphur Near to the boiling point, the chains start to break, the liquid is less viscous and it starts to evaporate.

Allotropes of sulphur When it evaporates it forms S2 molecules.

Allotropes of sulphur If it is poured quickly into water, plastic sulphur is made.It is “frozen” in long chain molecules like rubber.

Allotropes of sulphur It will eventually change back into S8.

Allotropes of Sulphur

Sulphuric acid – The contact process

The contact process Sulphur is burnt in air S(l) + O2(g) SO2(g)

2SO2(g) + O2(g) 2SO3(g) The contact process A vanadium oxide catalyst helps the sulphur dioxide react with oxygen to form sulphur trioxide 2SO2(g) + O2(g) 2SO3(g) reversible

SO3(g) + H2O(l) H2SO 4(l) The contact process sulphur trioxide reacts with water to form sulphuric acid (in a mixture of 98% sulphuric acid and 2% water) SO3(g) + H2O(l) H2SO 4(l)

The contact process

Uses of sulphuric acid Making fertilisers (ammonium sulphate)

Uses of sulphuric acid Tanning leather

Uses of sulphuric acid Making soapless detergents

Uses of sulphuric acid Cleaning metals

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)

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 also widely 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

Today’s lesson Electrolysis of brine

Brine is salty water (sodium chloride solution)

Electrolysis of brine

Electrolysis of brine Hydrogen is produced at the cathode Chlorine is produced at the anode The solution remaining is sodium hydroxide

Electrolysis of brine Hydrogen is produced at the cathode Chlorine is produced at the anode The solution remaining is sodium hydroxide Cathy’s Ankles (CatHy’s AnCl)

Electrolysis of brine Hydrogen is produced at the cathode Chlorine is produced at the anode The solution remaining is sodium hydroxide Copy please! Cathy’s Ankles (CatHy’s AnCl)

Electrolysis of brine Cathode (-) 2H+(aq) + 2e- H2(g) (SODIUM IS NOT FORMED (the sodium ion is more stable than the hydrogen ion in water H2O H+ + OH-)) Anode (+) 2Cl-(aq) – 2e- Cl2(g)

Electrolysis of brine Cathode (-) 2H+(aq) + 2e- H2(g) (SODIUM IS NOT FORMED (the sodium ion is more stable than the hydrogen ion in water H2O H+ + OH-)) Anode (+) 2Cl-(aq) – 2e- Cl2(g) Copy please!

Chemicals from salt

Chemicals from salt Copy please!