C6 - Chemistry out there

Energy transfers

• Give two reasons why the car industry want to develop fuel cells.
• Give three advantages of generating electricity with a fuel cell.
• Why is the reaction of hydrogen and oxygen described as exothermic?
• Which electrode reaction loses electrons in the fuel cell?

Redox Reactiong

• why does painting prevent rust/
• What happens to electrons in the process of oxidation?
• Write a word equation for the reaction between zinc and iron nitrate.
• Write a balanced symbol equation for the reaction betweem magnesium and iron sulfate.(FeSo4)

Energy transfers

• Petrol reserves will eventually run out. More laws being passed to reduce pollution from exhausts.
• The main product from the reaction is water with no nitrogen oxides. Fuel cells cause fewer disposal problems than conventional batteries. Fuel cells weigh less, making the car lighter, reducing  fuel consumption.
• Heat is given out.
• The reation at the negative electrode. 2H2=4H+Fe

Redox reactions

• Prevents oxygen or water reaching the surface of the iron.
• Electrons are lost
• Zinc+Iron nitrate = Zinc nitrate+Iron
• Mg+FeSo4=MgSo4+Fe

Alcohols

• What is the word equation for the production of ethanol from sugars?
• Explain what happens if the temperature is too hot during fermentation.
• What is the catalyst needed for the dehydration of ethanol?
• Write down the balanced symbol equation for the hydration of ethene.

Chemistry of Sodium chloride

• What are the different ways that table salt and gritting salt are made?
• Write down the equation for the discharge of sodium ions at the cathode.
• Why is the barrier used in the bells of the electrolysis of brine?
• Write the equation for the discharge of ions at the anode in the electrolysis of brine.

Alcohols

• Glucose=ethanol+carbon dioxide.
• Enzymes needed tor the reaction will be denatured.
• Hot alumimium oxide.
• C2+H20=C2H5OH

Chemistry of Sodium Chloride

• Using underground cutting machines. Pumping water down a borehole, dissolving the salt, pumping to the surface and evaporating.
• 2Na+2e=2Na
• Seperates the products
• 2Cl - 2e=Cl2

Depletion of the ozone layer

• How do the levels of UV light change when there is a depletion of ozone?
• Explain how ozone is able to absorb UV light in the stratosphere.
• How does a single chlorine atom cause the ozone to be destroyed?
• Write down two equations between chlorine atoms and the ozone to show the chain reaction.

Hardness of water

• Why does calcium carbonate dissolve in rainwater but not in pure water?
• Write the balanced equation of magnesium carbonate reacting in rainwater.
• Which kind of harndess of water do ion-exchange resins remove?
• Explain why concentrated salt solution is later added to ion-exchange resin.

Depletion of the ozone layer

• They increase.
• The UV part of the electromagnetic spectrium has exactly the right frequency to make ozone molecules vibrate. The energy of the UV is converted into movement energy inside each molecule.
• Chlorine free radicals attack ozone molecules, turning the ozone back into oxygen has and depleting the ozone layer.
• Cl+O3=OCl+O2    -    OCl+O3=Cl+2O2

Hardness of water

• Rainwater is acidic
• MgCo3+Co2+H20=Mg(HCO3)2
• Both kinds of hadness
• To recharge the sein column with Na ions.

Natural fats and oils

• How is bromine used to test for unsaturation.
• Why are unsaturated fats thought to be a healthier option in a diet?
• What happens during saponification?
• Explain how a saponification reaction works.

Analgesics

• What is the danger of an overdoes of paracetamol?
• What is an unwanted side effect of aspirin?
• What is the molecular formula of ubruprofen?

Natural fats and oils

• Bromine becomes colourless when shaken with an unsaturated compount.
• People whose diet is rich in unsaturated oils usually have lower levels of cholesterol. High levels of cholesterol can lead to heart problems.
• Vegetable oils are heated in large vats with sodium hydroxide solution.
• When facts react with sodium hydroxide the molecules split into a molecule of glycerol and molecules of soap. The reaction is a hydolsis reaction.

Analgesics

• Can cause liver damage.
• The stomach lining is attacked causing slight bleeding in the stomach.
• C13H18O2.
• The acid group COOH is reacted with a base such as sodium hydroxide.