I hope that the grade boundaries for chemistry will be lower <about an avg. of 40> for paper 22....
same here, last years june 15 22's grade boundary was 45 which was actually quite lower than expected cause that paper was so easy. but this year there was syllabus change, plus there were 5 questions, some of those were not so easy. so i am guessing it will be lower than 45 this time.
same here, last years june 15 22's grade boundary was 45 which was actually quite lower than expected cause that paper was so easy. but this year there was syllabus change, plus there were 5 questions, some of those were not so easy. so i am guessing it will be lower than 45 this time.
The product should be distilled immediately before the product undergoes further oxidation..
i mentioned about fractional distillation cause aldehyde's bp is lower so it distills off more quickly. plus i also mentioned "without reflux"cause reflux ensure the full oxidation instead, right? hope i get some marks here
i mentioned about fractional distillation cause aldehyde's bp is lower so it distills off more quickly. plus i also mentioned "without reflux"cause reflux ensure the full oxidation instead, right? hope i get some marks here
[QUOTE=olmomiau;64579499]For the paper 21, question 1, the part where you had to draw the paths of a proton and a neutron in an electric field, did you draw the proton deflected upwards? I did that, but also thought that due to the the mass of the proton being nearly 2000 times the mass of the electron, its deflection could be too small to be seen. What did you put? Also, on question 2, for the reactions of the period 4 compound, did you use the letter they gave in the question or the actual symbol of each element? Yes the proton will be deflected upwards and it's smaller than the electron's. I used the actual symbol of the element, but apparently I didn't read the question so I got sulfur and aluminium as the answers. I thought it was period 3. I lost the 7 marks. Stupid I know, what did you get? That was the only question I messed up in along with the first question in the second page about the successive ionization energies, I got it wrong, realized my mistake, I was like 'I'll change it in a bit'. But I did not, so I just lost 2 marks. I'm pretty sure of all of my other answers. So I guess I lost 9 marks only in total.
[QUOTE=Paranoid_Glitch;64580631]For the MgO acid question what did people write. I wrote that it would react to form a salt hence using up the MgO but seems there is more to it?What do you think?
I wrote that MgO is alkaline, hence it would react with the acid and a salt will be formed. I also mentioned that it's a neutralisation reaction.
Yes the proton will be deflected upwards and it's smaller than the electron's. I used the actual symbol of the element, but apparently I didn't read the question so I got sulfur and aluminium as the answers. I thought it was period 3. I lost the 7 marks. Stupid I know, what did you get? That was the only question I messed up in along with the first question in the second page about the successive ionization energies, I got it wrong, realized my mistake, I was like 'I'll change it in a bit'. But I did not, so I just lost 2 marks. I'm pretty sure of all of my other answers. So I guess I lost 9 marks only in total.
In question 2, if you got everything else right then you only lose 2 marks as it is error carried forward.
Yes the proton will be deflected upwards and it's smaller than the electron's. I used the actual symbol of the element, but apparently I didn't read the question so I got sulfur and aluminium as the answers. I thought it was period 3. I lost the 7 marks. Stupid I know, what did you get? That was the only question I messed up in along with the first question in the second page about the successive ionization energies, I got it wrong, realized my mistake, I was like 'I'll change it in a bit'. But I did not, so I just lost 2 marks. I'm pretty sure of all of my other answers. So I guess I lost 9 marks only in total.
I got the elements just below aluminium and sulfur (gallium and selenium)
[QUOTE=olmomiau;64582595]In question 2, if you got everything else right then you only lose 2 marks as it is error carried forward.
How can you be so sure? I've only seen ecf in moles. I mean, If I wrote Al2O3+6HCl=2AlCl3 + 3H2O that's not the right answer, so I'll just get a 0. Simple as that.