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That exam was awesome, easily 95%+ for me.

that's what I thought. I don't know where on earth the guy in my class got his answers from, he reckons he got them from the BOS website.

oh yeah, derr, you're right. That means the graph should shoot up for all molecules and then reestablish equilbrium by ammonia going up and h and n going down. So the graph everyone is taking as right is actually wrong. It should look like this:

I did that as well. It looks like there are three answers that work, and that must be an easy four marks.

mine was basically like that except I did it as an in place sort. I also did mine as generic so it didn't just have to have 8 indices in the array. But what I did was loop backwards from the end of sub array 1 and find where that slots into sub array two. When I found the spot I moved all of the...

What was the answer to that? I put D because I thought the town would put nutrients into the water and increase the biochemical demand and lower dissolved oxygen, and the quarry would increase pH since limestone is alkaline. But someone else reckons it is A. What does everyone else think.

The only time a graph shoots up is when you add more reactants or products such as to increase the concentration. eg. When you are making an ester, say you have pure ethanol and 1mol/L ethanoic acid and it gets to equilibrium then you add 10mol/L ethanoic acid it will shoot up because the...

I'm expecting 85%. I screwed up industrial chemistry, I forgot what process makes sodium hydroxide and thought it was the solvay process as in the next question. Apart from that I think I did quite good.

it works fine for me. Does it say incorrect password on the screen?

how very interesting. I only have one problem with that, what about the infinite series for sinx and the other trig series? They would have to be divided by two to get the correct answer. eg. Say you put sqrt(3)/2 into the formula, you would get pi/3 and the formula looks neat enough as it is...

I had a bruise on my little finger where it was resting on the paper after both exams and my neck and hand hurt.

yes, I agree. I threw all my english notes out as soon as I got home from the exam.

t = tan(x/2) is in our year 11 textbook. It's just a matter of remembering the formula. The question was show that cosecx + cotx = cot(x/2) If you remember your formulas you will remember that tanx = 2t/(1-t2), cosx = (1-t2)/(1+t2) and sinx = 2t/(1+t2) Therefore cosecx = (1+t2)/2t and...

I did four unit and according to what our teacher told us, the integral in question 4 was biased toward four unit students. Our teacher said that in three unit you aren't expected to work out the substitution and that it would be given to you, but in four unit you are. So I looked at it and...

I reckon I'll get about 50% if I'm lucky. I have 12 units however, and I'm killing the rest of my subjects, so I guess this one will probably end up not counting.

I thought it was quite hard, but I haven't seen past papers so I can't really say.

to answer the actual question they are what you are testing. You need an indicator to test them. I would be using universal indicator solution since it covers the whole range.

it's a dot point, so that's why we need to know it. It says identify that neutralisation is a proton transfer reaction. So we just need to know that it transfers a proton from the acid to the base and it becomes neutral.

Can you tell me how fats are esters. I thought esters were specifically the substances produced when an alkanol and an alkanoic acid are reacted. Then it gives the CH3(CH2)NCOO(CH2)NCH3 where N is a number depending on how long the chain is. Beeswax is also a natural ester. edit: my...

it's got nothing to do with unclean or contaminated equipment. You are supposed to clean your equipment properly before you do any titration. ie. Clean the burette with whatever you are putting in it, clean the pipette with whatever you are putting in it and clean the flask with distilled water...