I made the mistake of using wrong mass in p34 cuz it was tough and my mind stopped working
the mass in this in 25cm3 of each.. so 50cm3 total. Put in formula and you get the correct answer...Remember that the mass used is always of the liquid..
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Chemistry: Post your doubts here!
- Thread starter XPFMember
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the mass in this in 25cm3 of each.. so 50cm3 total. Put in formula and you get the correct answer...Remember that the mass used is always of the liquid..
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I made the mistake of using wrong mass in p34 cuz it was tough and my mind stopped working
the mass in this in 25cm3 of each.. so 50cm3 total. Put in formula and you get the correct answer...Remember that the mass used is always of the liquid..
Oh i got it 1 cm3 of water has a mass of 0.001 kg or 1 g
That's what we always use! I take it as a rule.. don't know the reason behind it.. But i think it's that the temperature change that occurs, is of the "solution" so we consider the mass of the solution.
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dummb me Im at my last Chem exam and I learn this now!!!!!!!
Any tips for tomorrows examm???
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Metallic9896
Haha, scary thing is I suck at Chem timing too. The best tip I can give you is what I follow myself. Don't think about revising the paper. Do it with such precision, care, and attentiveness that no need arises for a recheck. I put all my effort in the question I'm doing and once I'm done I forget about it, cause Chem questions are time taking on their own anyway, so one might as well put all of their energy and do it right the first time. If any question seems to be utterly difficult and takes more time than the average question, mark it with your pencil and come back to it and only it later. Forget the rest. Also, leave the isomer questions for the end. They take so much time and at least I tend to mess them up anyway so huge time waste.
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answer is A
cuz since O has an oxidation of -2 and H of +1
Cl should have an oxidation of +1 in order to make a total of zero.
so as there are two elements i.e. H and Cl with same oxidation states i.e. +1 the answer should be A.
i hope this helps
if m still not clear u can let me know
I also seem to mess up isomers a lot! thanks for the advice : p we now have a few hours to discuss q's. I have decided to also revise the entire syllabus. So that will take around 3-4 hours too.
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Yeah sure I'll be on and off here too. Good luck man!
I recommend especially periodicity equations of group 17 and the general oxides etc. as well as the AS Organic equations conditions etc. it's always good to revise them.
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I
Tysm i think we can take hydrogen oxidation state -1 right?answer is A
cuz since O has an oxidation of -2 and H of +1
Cl should have an oxidation of +1 in order to make a total of zero.
so as there are two elements i.e. H and Cl with same oxidation states i.e. +1 the answer should be A.
i hope this helps
if m still not clear u can let me know
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H always has a +1 state
so here it will be +1 too
n also recall the Cl reaction with NaOH
it makes NaClO right?
Cl has +1 state n Na has +1 too
HClO is a compound just like it
Cl reacts with water to make HClO in which Cl has +1 oxidation state n H also has +1
this can be found in the bleaching properties of Cl section
bleaching is in our syllabus
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H only exists as -1 in very rare circumstances. Not in this one. Here's a tip. If anything is joined to a more electronegative atom, the more electronegative one will take the cake and get the negative oxidation state. For example, N is more electronegative than H so in NH3, N is -3 and H is +3. O is more electronegative than N, so in NO, O is -2 and N is +2. F is the most electronegative, more than O. So in F2O, O is +2 and both F are -1 each. H is only -1 when it is more electronegative than the atom it is attached to or is bonded ionically too, and that is in the case of metal hydrides. THERE, in NaH for example, Na is +1 while H is -1. But normally H is +1. So for metal hydrides it has -1 but otherwise it's +1.
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http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_11.pdf
Q4 I dont understand what Np Pu means??
Q6 ??
Q17 ??
Q30??
http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_13.pdf
Q9 ???
Q21 ??
Q33 Statement 2 ; No particles have zero energy at either temperature. ?? What does this mean in context?
Q4 I dont understand what Np Pu means??
Q6 ??
Q17 ??
Q30??
http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s16_qp_13.pdf
Q9 ???
Q21 ??
Q33 Statement 2 ; No particles have zero energy at either temperature. ?? What does this mean in context?
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in q4 they r just metals neptunium n plutonium
this questions like radioactive decay in physics
n in q33 paper 13
it means that no particle is stationary
all particles have kinetic energy to some extent n they r moving n colliding
so its correct
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Did someone else too found March 16 and 17 chem p1s really really easy?
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Q4: The point here is to be concerned with the nucleon number and proton number. They already told you above that in a nuclear reaction, both the nucleon numbers and proton numbers remain constant, i.e. if you add up the nucleon number of the reactants, the sum would be equal to the nucleon number of the product, and the same would be in the case of proton numbers. So in the second equation, the reactant nucleon number is 238 + 2 = 240 while proton number is 92 + 1 = 93. Hence, the product nucleon and proton numbers should be equal to 240 and 93 respectively too. They gave you only one option, J, and have 2 neutrons added to it. The 2 neutrons contribute 2 nucleon numbers and no proton numbers. So J must be an element that has 240-2 = 238 nucleon number and 93 proton number. Both A and B qualify for the nucleon number. But how do you know which one has a 93 proton number? Go to the Periodic Table and if you search hard enough, you'll find that in the f-block, (the bottom two rows) we have Np and Pu. Np has a 93 proton number so A must be the answer. I'll do the rest and post them as I type them out. Hope I helped.
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i scored a 38 in m17
havent solved 16 yet
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Got 37 in both,i hope some questions from past papers are repeated tomorrow. :/
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http://justpastpapers.com/cie-9701-...question-paper-and-mark-scheme/9701_m17_qp_12 in Q39 why would propan-2-0l give yellow ppt with iodine?