http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w03_qp_1.pdf
Can anybody please explain question 16 and 28?
Can anybody please explain question 16 and 28?
We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
Click here to Donate Now (View Announcement)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w03_qp_1.pdf
Can anybody please explain question 16 and 28?
Thanks so much!Q16. Check that the oxidation state of silver before and after the reaction is +1, it means that it is neither oxidized or reduced. This effectively eliminates options B, C and D. silver chloride is insoluble and the silver complex formed is soluble.
Q28. Since this is a paper from long ago, I think this concept might be out of the syllabus?
The idea is that the H on the hydroxyl (OH) group can be exchanged with the D from deuterium.
R-OH + D-O-D --> R-O-D + H-O-D
If there are 3 hydroxyl groups, then 3 H can be exchanged with D.
Thanks soooòoooooooooooo muchQ4. Use any of the alkane as an example and construct a balance equation for complete combustion, for here, I'll use CH4
I prefer to use table, but not sure if the alignment shows when typed out.
CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (l)
10 .............70 ................0 .................. - .......... initial
-10 ............-20 ............ +10 ............. - .......... change
0 ............ 50 .............. 10 ............ - ............ final
Total gases at the end = 50 + 10 = 60 cm3, this fits option D.
Q5. A pi bond is when there is a sideway overlap of orbitals, which is reflected in option B.
Q14. Group II nitrates decompose based on the equation below:
2 X(NO3)2 (s) --> 2 XO (s) + 4 NO2 (g) +O2(g)
The loss in mass is due to the formation of NO2 and O2 gas, the left over mass is XO.
Mass of XO = 1.71 g
Moles of XO = 1.71/ (Mr of X + 16)
Mass of X(NO3)2 = 5 g
Moles of X(NO3)2 = 5/(Mr of X + 62)
since moles of X(NO3)2 = moles of XO
5/(Mr of X + 124) = 1.71/ (Mr of X + 16)
We can solve for Mr of X using the normal maths approach, but it might be faster to do trial and error from the Mr of the four options.
Mg : 5/(24 + 124) does not equal to 1.71/ (24 + 16)
Ca: 5/(40 + 124) = 1.71/ (40+ 16)
Therefore, answer is Ca.
Q39. Sulfuric acid will turn the alcohols in options 1 and 2 into alkenes, which will undergo oxidative cleaving with acidified KMnO4 (decolourises)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_11.pdf. Q10 ans D Q29 ans B Q35 ans C
Hey! Can someone please solve Q 31 in http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s08_qp_1.pdf
Got it thank youhmm...Try creating 3 balanced equation for their combustion. If you are still stuck, then I'll provide the answers.
I'll discuss this as a theoretical thought procedure, rather than an attempt to predict what experiment is expected.
Some of the procedure are straightforward in theory, but not easy to carry out accurately with limited lab apparatus.
The amount of CaCO3 could be measured by
1) heating mixture to decompose CaCO3 and measuring loss in mass (hard to achieve the decomposition temp)
2) heating mixture to decompose CaCO3 and measuring volume of CO2 (very inaccurate, hard to set up apparatus, temperature affects volume, need to assume no CO2 lost)
3)Dissolve mixture in water, filter the mixture and collect CaCO3 as residue. Heat to dry CaCO3 and weigh it. (most straightforward of all 3 methods).
ThanksOut of every 100 g of fertilizer, 30 g is P205.
Out of 30 g of P2O5 ,
mass of P
= (2 x Mr of P/Mr of P2O5) x 30 g
= (62/142) x 30 g
=13.1 g
You haveHelp please, how do we solve this? Answer is C
For almost 10 years, the site XtremePapers has been trying very hard to serve its users.
However, we are now struggling to cover its operational costs due to unforeseen circumstances. If we helped you in any way, kindly contribute and be the part of this effort. No act of kindness, no matter how small, is ever wasted.
Click here to Donate Now