Longtime vet here; did Acids and Bases when it was a topic in 2013/2014. I am 160% sure the Nats exam is going to be very run of the mill and stuff an AP chemistry grad can do no problem provided they're fast enough and familiar with the Chem Lab format. It's the exams along the way that trip you up.
[quote ="Dinoswarleafs"]What are you guys putting on your reference sheet for acids & bases? I put the ions on the rule page and a table of Kas (if weak) and uses of the acids and bases they listed. I was also going to put a list of indicators but it says that the ranges will be provided so that seems pretty useless. I don't really understand what extra stuff there is for titrations if we're not doing buffers until state. Do you guys usually put a ton of stuff on the sheet you get to bring?[/quote]
Depends on the topic, but problem solving and quickness are the most important assets for acids/bases. The Ka table could be useful. Also would recommend the structures of the common acids in the rules (okay, just ascorbic acid). I wouldn't waste time on indicator lists. Also recommend Henderson Hasselbach and sample problems of how buffers work for each step of the titration curve. I guess there is extra room for proctors to fit in general ideas of titration, not just acid and base titrations.
PeptoBismol wrote:Do any veterans know how lenient on significant figures? I was doing some problems and I found that answers to weak acid / base pH were sometimes different by at most ~.1 depending if you count "-x" as negligible or not even when you can use 5% rule. Would my answer still be correct if it was .1 off?
Depends on the proctor, but most proctors didn't care as long as it was reasonable. I usually put 3 for everything and I as fine. I'm not sure what the stance is on 5% rule. I've seen answer keys that gave points for doing it even when it wasn't needed, and ones that didn't care.
Unrelated to the quotes above but I'd also encourage you to check out more difficult acid/base questions such as the "I dissolve AgC2H3O2 in HC2H3O2; what's the pKa?" type. Also, as mentioned above--calculations at each step of the titration curve.
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