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• Biodegradable and Compostable are NOT the same.Explaining Sacrificial protection
E.g. Protecting Iron by with Zinc (a more reactive metal) or tin (a less reactive metal,..still works though, but it acts just like paint and only helps by stopping the iron from being exposed to the air (by coating the whole iron object) thats all...its just like paint, but its A BIT better cuz paint only needs a little scratch...)
Just remember, more reactive metal is better, cuz even if iron is exposed, the zinc will oxidize before it (cuz its more reactive) and conduct the electrons to iron to prevent iron from oxidizing
See, these type of concepts are likely to be asked in paper 3
Also, in organic chemistry, they can also ask you to compare 2 organic compounds (I remember there was a Q about discuss 2 advantages of PLA ( poly lactic acid, which is a fuel made from corn starch) with petroleum-based fuel
Now, since PLA is made of corn starch, its made by plants, so if you have a plant that makes corn starch, then as long as the plant the plant's alive, you can keep on extracting the corn starch and make PLA, so you can say its a renewable source of energy or thats its not finite like petroleum based products and the second advantage is that its biodegradable and it breaks down naturally (though, I didnt get why thats a good thing because since its a fuel, isnt it better if its NOT biodegrable cuz we can store it and use it when needed?... If anyone knows the answer to this question please let me know
Also:" Suggest an explanation why making and using biodiesel has a smaller effect on the percentage of carbon dioxide in the atmosphere than using petroleum-based diesel." (2 mark Q)
A: Burning both fuels makes carbon (1 mark) (So? How does that explain why biodiesel has a smaller effect...clarify this one too plz
growing plants to make biodiesel removes carbon dioxide from atmosphere (1 mark) (yeah cuz you're gunna have to grow the plants anyway to make the biodiesel, so growing those plants will automatically reduce the levels of CO2, so biodiesel has a smaller effect on % of CO2)
This is just a bit of revision for Chem paper 3, hope it helped guys
Would really help if you guys also post more revision stuff on this thread, and other topics that might come as well ( and a good application of the topic (a Q which showed up in recent papers) plz
Thanks in advance
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