Past Paper 2 Lost marks Flashcards
What You Pieces of apparatus could the student use to find the rate of production of hydrogen gas 
Syringe and stopwatch
Explain what would happen to the nails in each of the test tubes
Tube 1 (nail) rusts because air and water are present
Tube 2 (nail) does not rust because no water present
Tube 3 (nail) does not rust because no air / oxygen
Tube 4 (nail) does not rust because paint is a barrier (to water / air / oxygen)
Tube 5 (nail) does not rust because stainless steel resistant to corrosion
Magnesium is fixed to some steel ships Explain how this prevents the steel from rusting
magnesium is more reactive (than Iron)
(So magnesium) provides sacrificial protection
Explain why alaminium window frames do not corrode after they are made
(aluminum has a coating of) aluminum oxide
(so the aluminum oxide) protects the metal (from further corrosion)
Name the functional group HOOC
carboxylic acid
Why does this type of polyester polymer melt when it is heated
Because it’s a thermal softening polymer which can melt unlike thermosetting polymer because thermal softening polymers have a weak intermolecular forces
What is matrix material description
A matrix material is a homogenous and monolithic material in which a reinforcement system of a composite is embedded and is completely continuous 
what is a polypeptide material description
A polypeptide material is in polymer made up of amino acids polypeptides are formed by peptide bonds between amino acids
What description of material are Glass fibres and Polyesters
Glass fibres = Reinforcement
Polyesters = Matrix
How do you test for aluminum
Add sulfuric acid, should creat white precipitate
Explain how the green house gasses keep us warm
Greenhouse gases absorb and emits radiation in the infrared range which we feel as heat shortwave radiation is emitted by the sun and mostly passes through the earths atmosphere the Earth surface absorbs most of this and re-emits it as infrared radiation at a longer wave length some of this infrared radiation is transmitted through the atmosphere back out into space on some of it is absorbed by greenhouse gases in the atmosphere the greenhouse gases emit infrared radiation in all directions some out in two space and some back towards earth which is then reabsorbed
How do you test for unsaturated hydrocarbons
Add bromine water
changes from orange to colorless
Explain why a low pressure is used
Higher yield and fewer moles on left hand side
