OCR Salters Chemistry of Natural Resources 2848

the number of moles of sodium hydroxide was 21.6/1000=0.0216

number of moles =volume x conc

0.0216 x 0.0100 =2.16x10-4

planks constant questions

346kJ i think it was?

346 x 1000 =346000 this is to convert it into joules

346000/6.02x1023

=5.75x10-19

I revised that for chemistry by design but I panicked in the exam because there were so many conditions and stuff to remember. I was mixing it up with making alcohol from C=C - concentrated h2so4...

Yea Bakelite I remember that in storylines... I just guessed poly(ethyne) because I forgot in the exam... and some of the questions came up in past papers that I did the day before but I couldn't remember I wasted like 1 week on this exam only to do worse than last year...

it was 99.5% pure so the impurity was 100-99.5% so that gives an impurity of 0.5%. 0.5%/10000

= 5x10-5 ppm

Yup that looks right. That was the Avogadro's constant question. The plank one was the next bit. You take the answer you just got and divide it by 6.63 x 10^(-34)

planks constant questions

346kJ i think it was?

346 x 1000 =346000 this is to convert it into joules

346000/6.02x1023

=5.75x10-19

Did you get 8.42 x 10^14 for the avogadros constant?

I revised that for chemistry by design but I panicked in the exam because there were so many conditions and stuff to remember. I was mixing it up with making alcohol from C=C - concentrated h2so4...

Yea Bakelite I remember that in storylines... I just guessed poly(ethyne) because I forgot in the exam... and some of the questions came up in past papers that I did the day before but I couldn't remember I wasted like 1 week on this exam only to do worse than last year...

i think so bt i think i've done it wrong i think it's meant to to be to the power of 15 because when you divide by powers you minus them -34--19 =15

I don't remember standard form. Not done it since GCSE, and that was hardly anything. I tyed it into my calc and I got that so I just wrote it down. Just gonna have to wait and see now I guess

i wrote it down how you did aswell!

you could have poly(ethene)/ldpe/hdpe/conducting polymers/poly(ethyne)/Teflon

i put teflon

silver chloride is a white precipitate( remeber that from past exam)

i also got 1-triflouro,2-flouroethane?

also temp one: less molecules will have an energy greater than that of the activation enthalpy, less sucessful collisions, less collisions per unit timeslower rate of reaction (THAT WAS WEIRD THOUGH! IT WAS LIKE ASKING YOU THE OPPOSITE WITH A LOWER TEMP EXPLANATION)