Chem theory

[MambaMent..]

Hey, for my upcoming sac on a burning of alcohols prac apparently there's significant focus towards difficult theory questions in relation to the prac. What would you guys say the best way to prep for this kinda thing is? thanks in advance!!

[Yertle the Turtle]

Hey, for my upcoming sac on a burning of alcohols prac apparently there's significant focus towards difficult theory questions in relation to the prac. What would you guys say the best way to prep for this kinda thing is? thanks in advance!!

In general just revise the general combustion equations so that you know how those work. Then also generally revise the stoichiometry calculations, and if you have that basic knowledge, you should be fine so long as you know when to use those.

[kaustubh.patel]

I made a few mistakes myself so this is a good opportunity to reflect upon. In the Q=MCT the mass is of the water in the solution absorbing heat not the entire mass of the solution including the solute. The experimental values will always be less than the true theoretical values (which are calculated by complex calculations with the bond energies of the molecules reacting), this is because of the 1st law of thermo-dynamics as no system is 100% efficient and thus not all the heat will be absorbed by the water majority of it will be released to the surroundings. More simple stuff like some alkanols will not burn clean and leave unburnt soot on the bottom of the container which will act as an insulator and prevent majority of the heat transferred to the water. And similarly the volatile alkanols will evaporate if there's no cap covering the burner.