Chemistry: Post your doubts here!

[smartangel]

The Cl radical can bond to any CH3 or CH2 carbons by substituting a hydrogen. There are 5 such carbons here, however there are 3 CH3 groups bonded directly to the alpha central carbon. If the Cl radical bonds to any three of this, you get the same molecule. The 3 CH3 groups form only one type of molecule. There are another two carbons which Cl can bond to, which makes 3 Chloroalkanes in total.
Answer: C. 3 (I checked)
Sorry for the messy explanation, not very good at this, ask me to clarify if needed
EDIT: Fixed typo

no its a great explanation..i got it..thanks

 

[angelgirl:)]

question no32 m/j 2010 ppr 11...some 1 plz help me out ...withthese kind of questions ...coz i can never solve like this kind of question...

 

[Student12]

216 grams is 4NO2 + O2
N=14grams per mol
O=16 grams per mol

Yea i understood that part.. but i'm still confused. Why did you take 4 for NO2? & the 2 for XO.
We don't take the values of the balancing part for the Molar mass isn't it ?

 

[Oliveme]

help with question 11 please. http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w06_qp_1.pdf

 

[Student12]

question no32 m/j 2010 ppr 11...some 1 plz help me out ...withthese kind of questions ...coz i can never solve like this kind of question...

It would be easier for others if you give the link of the paper.

 

[saudha]

It would be easier for others if you give the link of the paper.

http://www.xtremepapers.com/papers/... AS Level/Chemistry (9701)/9701_s10_qp_11.pdf

 

[saudha]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_11.pdf

Q32
sorry .... angelgirl ...im not getting th answer

 

[smzimran]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_11.pdf

AoA,
1 is redox
Br goes from -1 to 0 [oxidation]
S goes from +6 to +4 [reduction]

2 is not redox
P is same at 5
Br is same at -1

As 2 is wrong, you dont need to see 3
Definitely D is the answer but i will solve to clear any doubts!

3 is not redox
N is same at 5
Br is same at -1

 

[Student12]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_13.pdf

QUESTION - ANSWER
15 - B
23 - A
25 - C
36 - A

Someone plz explain ?

HELPP !!

 

[smartangel]

35 In a car engine, non-metallic element X forms a pollutant oxide Y.
Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1 mol of Y reacts
with ½ mol of gaseous oxygen.
What can X be?
1 carbon
2 nitrogen
3 sulfur
why cant it be carbon?

 

[saudha]

AoA,
1 is redox
Br goes from -1 to 0 [oxidation]
S goes from +6 to +4 [reduction]

2 is not redox
P is same at 5
Br is same at -1

As 2 is wrong, you dont need to see 3
Definitely D is the answer but i will solve to clear any doubts!

3 is not redox
N is same at 5
Br is same at -1

thxx a lott really

 

[angelgirl:)]

AoA,
1 is redox
Br goes from -1 to 0 [oxidation]
S goes from +6 to +4 [reduction]

2 is not redox
P is same at 5
Br is same at -1

As 2 is wrong, you dont need to see 3
Definitely D is the answer but i will solve to clear any doubts!

3 is not redox
N is same at 5
Br is same at -1
thanks...so for solving the redox questions u can jtake any example u want...and then carry out the calculation? isnt it?
and soory for not posting the link coziam soling in the paper...

 

[angelgirl:)]

35 In a car engine, non-metallic element X forms a pollutant oxide Y.
Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1 mol of Y reacts
with ½ mol of gaseous oxygen.
What can X be?
1 carbon
2 nitrogen
3 sulfur
why cant it be carbon?

ohhh even i have doubt in this question...

 

[smzimran]

ohhh even i have doubt in this question...

35 In a car engine, non-metallic element X forms a pollutant oxide Y.
Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1 mol of Y reacts
with ½ mol of gaseous oxygen.
What can X be?
1 carbon
2 nitrogen
3 sulfur
why cant it be carbon?

It is because Carbon is not there in the car engine!
Yes, carbon and CO maybe produced by incomplete combustion of hydrocarbon fuels but they are produced outside (not in the engine itself)

 

[angelgirl:)]

ohhh even i have doubt in this question...

plz some1 give an explaining for this question...

 

[saudha]

It is because Carbon is not there in the car engine!
Yes, carbon and CO maybe produced by incomplete combustion of hydrocarbon fuels but they are produced outside (not in the engine itself)

here it is angelgirl

 

[smartangel]

It is because Carbon is not there in the car engine!
Yes, carbon and CO maybe produced by incomplete combustion of hydrocarbon fuels but they are produced outside (not in the engine itself)

oh ok so instead of carbon if they give hydrocarbon as an option it'll be included in the answer?

 

[angelgirl:)]

It is because Carbon is not there in the car engine!
Yes, carbon and CO maybe produced by incomplete combustion of hydrocarbon fuels but they are produced outside (not in the engine itself)

ok...thanks

 

[smzimran]

oh ok so instead of carbon if they give hydrocarbon as an option it'll be included in the answer?

No,
Read the question it says a NON-METALLIC element!
Hydrocarbon is a compound

 

[smartangel]

No,
Read the question it says a NON-METALLIC element!
Hydrocarbon is a compound

oops. my bad oh and btw they give this question again n again with some variation. in one of them they said it is a polar molecule. CO is a polar molecule right? sorry i knw its like basic stuff but im kinda freaking out right now!