Chem p6 v2

[anonymous123]

In question 1 wasn't the suitable method distillation? :x
and the reaction b/w zinc and CuSO4 i wrote hydrogen gas bubbles off and copper is formed...no?
one more thing..the precautions i stated were fume cupboard and gloves for the conc HCL is it correct?

 

[jbatcampnou]

Question 1 should have been Distillation, 'cause they asked about separating the WATER. If we had used the evaporating dish, we would have got the salt, and the water would have evaporated.
By the way, for question 1, part (a), they asked which was more suitable to measure out 70cm^3 of sodium chloride solution (either one of measuring cylinder, or burette). Which one was it? My guess was measuring cylinder, 'cause even though the burette is more accurate, it's used to measure out smaller quantities. They asked 'SUITABLE', not accurate.

For the Zinc and Copper Sulphate, I am more than 100% sure that hydrogen is NOT released. They even gave the FULL equation. The reaction was a displacement reaction. And it showed that Zinc displaced Copper from its compound. And where would the hydrogen come from anyway?! It's a SULPHATE compound

And CRAP! The last question, instead of writing that the fuel which brings about the higher temperature change in a SPECIFIC PERIOD OF TIME produced more energy, I wrote that the fuel which brings about the OVERALL higher temperature change produced more energy. Now there are arguments for and against both. If a fuel brought about the higher temp. change in a specific period of time, it WOULD imply that the fuel produced more energy, but only in a specific period of time, and it would not be a good evidence of which fuel produces more energy, 'cause maybe the other fuel produces MORE energy, but slower. And when we use the same mass of fuels, we should let both fuels burn COMPLETELY, and then compare the temperature change they brought about (we need to let their WHOLE energy content be converted), and then the fuel which brought about the higher temperature change could be said to have produced more energy. On the other hand, we could compare the MAXIMUM temperature reached by either, and conclude that the fuel which brought about the higher MAX TEMPERATURE produced more energy.

Nevertheless, what is done is done! I just hope we all get awesome grades! And that we do even better in the rest of the components! Cheers!