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dickyjones wrote:I'd say that the best way to practice chem lab would be to learn the science behind it before you start team practices (or just out of team practices) so that you can use your time at school when you have access to lab equipment to practice titrations and other acid/base labs. I think that's pretty much what our team did last year, and they ended up doing pretty well.

"They ended up doing pretty well"? I'd say your team ended up doing a little better than "pretty well"! They only won nationals, did they not?

Studying for us meant madly completing every AP practice question we could find relative to the topic. But don't put off actually doing the labs- you want to make sure to ask your teacher what sort of materials might be given to you- last year for a common filtering lab at NY states, we were expected to use a vacuum system hooked up to the sink to drain water faster- our school doesn't have the money for those, so we had never seen them before and we had no idea what knobs to turn. Luckily one of the proctors sympathized.

I think since they took out Circuit lab, they should've done electrical engineering or something circuit-related for Physics lab

For the titration race, would the accuracy of the results matter more, or the speed of the titration. If speed is weighted more, I could just open the tap on the burette and close it for a (very rough) approximation.

I think the speed is only used as a tiebreaker.

I think the titration race makes it sound like fun. in class whenever we have to do a titration my friends and i always race. it's not super accurate, but its fun!

how do you practice to do good on titration race? i mean, the titration lab is pretty simple; and do you think that i should practice on diprotic acid and stuff? thanks.

Yeah, it's not that difficult...and is probably way overcurved. Hopefully, the judges will find a way to score it fairly. To practice, just make someone on your team make an acid/base of some given molality and then do the titrations. Try to do it at least once with each of: a pH probe, phenolphthalein, burettes, and pipettes. Just get a good method with your partner that won't leave one of you doing nothing while the other does the whole titration.

I wouldn't expect diprotic acids for the titration race, but I'd prepare for them for the rest of the labs/questions. They could do more than one titration the way the rules are written.

what do they mean about "calculating standard deviation"; can anyone please explain? thanks.

It means that you have to do the titration more than once (probably, three times would be a good number).

Standard deviation is the square root of the sum of the deviations of each trial the mean of all trials divided by one minus the number of trials....yeah...look here