Chemistry: Post your doubts here!

[Thought blocker]

Cn dere b H- bonds b/w Ch3CH2CH2NH2 molecules? Lyk the +ve H of 1 molecue to a -ve N of a diff molecule?

Yes it can have. Strong electronegative element N is present in other propanamine that can form H bonds with hydrogen present in the other propanamine.

 

[student2]

ok. cn sm1 tell me if the chem P5 pprs hv a format which does nt hv planning experiments lyk b4? I dnt see ques lyk tht in recent yrs so wondering if it's chnged?

 

[krishnapatelzz]

ok. cn sm1 tell me if the chem P5 pprs hv a format which does nt hv planning experiments lyk b4? I dnt see ques lyk tht in recent yrs so wondering if it's chnged?

read syllabus .. planning is a part of the paper

 

[Dharyl]

hi all, can somebody help me, i am looking for a revision book for ATP o level chemistry sylab:5070, thanks

 

[teachyourself]

hi all, can somebody help me, i am looking for a revision book for ATP o level chemistry sylab:5070, thanks

https://www.youtube.com/channel/UCTgPevMIji1ZyP4IPhmwDsQ
https://www.youtube.com/user/MrChuaTungKian
https://www.youtube.com/results?search_query=test+for+anions
https://www.youtube.com/results?search_query=Tests+for+aqueous+cations
https://www.youtube.com/results?search_query=Tests+for+gases
https://www.4shared.com/office/vgquggcX/Study_Quide_0620.html

 

[Need A*]

For All to use

 

[drowning-in-studies]

How do you find the conc of Ca2+ and Mg2+?

 

[drowning-in-studies]

(ii) The partition coeffi cient of a particular pesticide between hexane and water is 6.0.
A solution contains 0.0042 g of the pesticide dissolved in 25 cm3 of water. The solution is
shaken with 25 cm3 of hexane.
Calculate the mass of pesticide that will be dissolved in the hexane layer at equilibrium
Ans is 0.0036g

 

[drowning-in-studies]

How do we know where the Br attaches in 4 (b) (ii)?

 

[drowning-in-studies]

Why is [Fe3+(aq)] = 0.2 mol dm–3 in (d)?
And can you explain (c) (iii)?

 

[krishnapatelzz]

View attachment 61695 View attachment 61696
How do you find the conc of Ca2+ and Mg2+?

this is the paper which i gave exam of i have solved it i will post the reply in 5 min

 

[krishnapatelzz]

View attachment 61695 View attachment 61696
How do you find the conc of Ca2+ and Mg2+?

 

[krishnapatelzz]

View attachment 61695 View attachment 61696
How do you find the conc of Ca2+ and Mg2+?

 

[drowning-in-studies]

How does the moles of Ca2+ equal to the mole of H2Y2–? Isn't the ratio from the equation 1:2?

 

[krishnapatelzz]

How does the moles of Ca2+ equal to the mole of H2Y2–? Isn't the ratio from the equation 1:2?

not for that , because y2- ion has charge 2- and so needs only one ca2+ . note - mg2+ was removed by precipitating so only ca2+ is left .

 

[drowning-in-studies]

not for that , because y2- ion has charge 2- and so needs only one ca2+ . note - mg2+ was removed by precipitating so only ca2+ is left .

ahh ok thanks

 

[HarshuOP]

Could anyone do 9701/52/MJ/15 Q2 part d part 1? Mass of HX. How to ? Thanks

 

[teachyourself]

Can some tell me where to find past papers related to organic chemistry As level 9701

buy a topical past paper book if it is available

or download from here
http://www.gceguide.com/topical-past-papers/

 

[student2]

Cn any1 pls tell me if group 4 is removed frm da syllabus? (Ge/Sn/Pb etc)

 

[teachyourself]

Cn any1 pls tell me if group 4 is removed frm da syllabus? (Ge/Sn/Pb etc)

check the syllabus