My teacher said that it was one of the 2005's...
I dont know about all the questions coz we only did 2.
OK look I'll tell you thie question I'm having difficulty with:
Firstly, the question required me to measure the mass of a 250 ml beaker. Then, I was required to pour some amount of salt into the bearker & measure its mass.
After that I filed a measuring cylinder with about 180cm^3 of water & poured it into the bearker with the salt. I stirred the solution.
On to the calculations bit:
"Assuming that 1 cm^3 of water has a mass of 1g & that there is no change in liquid vol. as the salt dissolves, calculate the theoretical value for the density of the salt sol."
Ok so density=mass/vol
Mass= 180g + 5g
So density = 1.027cm^3
Q2] Use the apparatus provided & the top pan balance to find the density of the salt sol experimentally.
I went along this way-
I poured some of my salt solution into the measuring cylinder & then weighed the mass of this salt sol & recorded its vol.
Using these figures, I calculated the density which came out to be 1.109g/cm^3
Q3] This was a disaster!
"Estimate the % uncertainty in your value of vol of the sol"
What I did was:
I used the 'Experimentally found' density to find the vol of the sol...
So I found out the % uncer. between my theoretical vol & my exp. vol
i.e between 166.8 & 180.
My teacher said this was wrong & that in a measuring cylinder the % uncert. is always 0.5%...she told me then to write 0.5%.