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just going over my folder today... my teacher says that halogen gets priority over the alkyl (provided the total numbers.. or sum of locants.. are the same of course) but he also says that the most electronegative halogen gets priority I mean, his source comes from one of those people or...

yes heating converts calcium hydrogen carbonate to CaCO3. so its a bit of both factors. I think what happens is this: calcium hydrogen carbonate (I write it coz Im not sure what the formula is... Ca(HCO3)2?) is soluble in water, and when you put in soap the Ca2+ attaches to it. when heated...

whats wrong with unsw? where r u btw?

hmm you get a different answer to ND I personally believe in him unless u can provide a method.

have u actually done all of them??

probably its best to worry about this at university ;) HSC wont care

Clearly, by inspection, I forgot to mention that a,b,c must all be positive :)

I think your diagram isnt a very good example. methyl will get 4 no matter how you name it...

hmm.. nope. you express hardness as the mass of CaCo3 just for a standard (and you add or hypothetically add the CO3 yourself). Maybe its like a tradition and I dont know why they first started doing this. what it measures is the concentration of Ca2+ and Mg2+ ions collectively, with Mg2+...

do my sample question :p

there are many... some are: area under curve (trapezia, rectangle, etc) squares cant be negative (such as when proving LHS-RHS > 0) also the results that a^2 + b^2 >= 2ab and (a + b)^2 >= 4ab are sometimes used and swapping variables also the ideas that inequalities can be added and...

um what do u mean? this particular question or all inequality questions in general?

(a) compounds that cannot be removed by boiling (b) salts such as calccium and magnesium sulfate (c) calcium and magnesium hydrogen carbonate (d) none of the above well for this Q it must be (c), but there might be a Q where u need to choose between calcium carbonate and calcium hydrogen...

its a totally identical thing ^_^ the idea is that the approximation will be less than the exact area. why? because the curve of ln(x) is concave down and if you try to draw the trapeziums they'll be all under the curve, so the approx area will be less than actual area. some other Q's use...

its in the 2U course.. remember when doing simpson's rule and trapezium / trapezia / trapezoid / trapezoidal rule (im not sure which term is the most correct haha)

so neither alkyl nor halogen atom gets priority in the number?

oh its by inspection!! (again) :p :p :p :p :p the inspection method is: you see on the RHS of the first line that ln2 will be repeated twice, ln3 will be repeated twice etc (but lnn will not be repeated) or you can also use the full trapezium rule to work that out (the rule which combines...

that means you're using tk and tk-1 saying tk+1 automatically corresponds to nCk+1 anyway I happened to post in the Binomial Theorem Q thread, quoted below: well, suppose it turns out that T_(k+1) / T_k > 1 when k < 4.2 so, T_(k+1) is bigger than T_k up to k = 4 and the biggest term is...

so, then conclusion is, you dont need to learn it :p

A question I saw says: "Temporary hardness of water can be caused by:" and the answer is "calcium and magnesium hydrogen carbonate" (multiple choice) Is it the carbonate or the hydrogen salt that makes the hardness temporary? (or perhaps both?)