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Chemistry: Post your doubts here!

S

smartangel

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Nibz said:
A wrong. In Al -> Metallic bonds. Phosphorus Covalent
B wrong. Chlorine -> Covalent. Argon -> monoatomic. No bonds.
D Right. Sulphur -> Covalent . Chlorin -> Covalent
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thanks. just see if you can help me with the other questions i"ve posted above. thanks again:)
 
roadtrip9o9

roadtrip9o9

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In polymer there are many monomers so moles of the monomers will always decrease when they form a polymer ... So 1 (it wudnt remain the same) ... so when one is wrong answer will always be 'C' for these type of questions
 
hmlahori

hmlahori

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Can someone please explain these paper 1 questions?
​
Q6 How is hydrogen more ideal than nitrogen? ​
Q11 How should this question be solved?​
​
Q21 How does the compound have 5 double bonds. I counted 6(one in the side chain and 5 in the cyclohexene ring due to presense of just one hydrogen in it.)​
​
 
étudiante

étudiante

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USMAN ALI (MANI) said:
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_4.pdf

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_ms_4.pdf

question 2 part b plz
I can see the ans. from m.s but can any one explain me how to drive the order of reactions here??? with respect to each??
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only substances in the slowest step r der in the rate eqn... thus if a substance is not present in da slow step, the order will become 0 automatically...
for the other substances, see the no of molecules of that substance involved in the slow step... the order will be the same number...
for the first one for instance..
step 1 doesnt have H= so its order is 0.. and there is only one molecule each of H2O2 and I- thus the order with respect to these two will be 1..


for step 3... its slightly different... we need to see how many molecules of the substance have been used up before as well... if u look back, we already used 1 molecule of I- in step 1 n 1 is again used in step 3 hence the ordr will be 2 with respect to I-
 
Jaf

Jaf

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geek101 said:
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w07_qp_1.pdf Q9, someone! good luck to y'all!
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Moles of metallic salt that reacted = (50/1000) * 0.1 = 0.005
Moles of sodium sulphite that reacted = (25/1000) * 0.1 = 0.0025
Therefore, the metallic salt and sodium sulphite react in the ratio (2:1).

Moles of electrons produced when 0.0025 moles of the sulphite ions react = 0.005 (mole ratio is 1:2 from equation).
Therefore, the mole ration of electrons:metallic salt is 1:1. Hence, each metal gains one electron. So the oxidation number changes from +3 to +2. Answer is B.
 
leadingguy

leadingguy

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geek101 said:
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w07_qp_1.pdf Q9, someone! good luck to y'all!
Click to expand...



mol of metalic salt n= cv

n= (0.10) . (0.050) = 0.0050
mol of sulphite n =cv

n= (0.10) . (0.025) = 0.0025

it has been given that 0.0050 mol of metal reacts with 0.0025 mol of sulphite mol ratio 2:1 metal/ sulphite

now when two electrons are released frm the sulphite's one mole.

only half of the released wil react with one mole of metal as shown above mol ratio 2:1

it has been given that the original oxidation no. of metal is +3 so when 1 elctron wil be added it wil be +2 !!!!


so it wil be the new oxidation no, i guess so B is to be the ans m i ryte??
 
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