I do not understand how Gortex can be breathable and waterproof, because the breathable PTFE is layered on top of nylon or polyurethane, which isn't breathable, so surely the sweat wouldn't be able to get out.
Also, how do perfumes evaporate because where do they get the heat energy to turn from a liquid to a gas?
In crude oil are the hyrdocarbons only alkanes or are there alkenes too. if there are alkenes too how can you crack longer hydrocarbons to form smaller alkenes and alkanes, because wouldnt the alkenes be in there too. do you only burn alkane hydrocarbons for fuel?
What is photochemical smog and how is ozone formed from it. the textbook also says that ozone causes breathing difficulties but it is not beneficial to stop uv light coming through?
i do no understand what allotropes of carbon are - like fullerenes?
in the rocks topic my textbook says that in sedimentary rock water is squeezed out due to pressure, which i understand, but i dont get when it says 'fluids flowing through the pores desposit natural mineral cement' ??
thanks if anyone can reply - its justs my chemistry GCSE is tomorrow!