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Biology; Chemistry; Physics: Post your doubts here!

UziB

UziB

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SalmanPakRocks said:
Topic people, back on topic.
View attachment 11042View attachment 11043
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Answer to Q5 should be D i.e 2.00mol/dm3. Since 1 mole of H2SO4 dissipates 2 moles of hydrogen, then 0.025 moles of H2SO4 will dissipate 0.050 moles of Hydrogen. Keeping in mind that they have asked the HYDROGEN ion concentration, we can use the formula i.e concentration = moles/vol(dm3) to find the answer, i.e 0.050/0.025 = 2.00mol/dm3.
 
daredevil

daredevil

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ashiqbal said:
the question is like this: the same mass is used every time, right? let mass be x
then moles of zinc = x/65
moles of magnesium = x/24
the equation for both reaction is same, so one mole of metal produces 1 mole of hydrogen.
therefore, moles of H2 with zinc = x/65, whereas moles of H2 with Mg = x/24!
x/24 is greater, so greater volume with magnesium!
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thnks a load dude!! :D that was big tym help ... i always got stuck on that question :/
 
daredevil

daredevil

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Dukeofwin said:
Roses are Red
Violets are Blue
People are so rude
For which i don't have a Clue!:cool:
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nah didn't wanna b rude but its the exam phase so.... and saying that the exam is going to b tough is hitting a nerve :LOL:
anyways thanks for the hints anyways..... u were ryt we need to b prepared for it. (y)
 
F

faira

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I just realised the q.no. 8 in chemistry's red spot past papers is incorrect so the answer also ought to be incorrect. so please sum1 tell me what would be the answer to
Q. ethane has structure as shown
H H
I I
H-C-C-H
I I
H H
i.e C2H6
how many of the electrons in a ethane C2H6 are not involved in bnding?
A)0
B)2
C)4
D)8
plz sum1 help me out a.s.a.p.
 
multixamza01

multixamza01

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faira said:
I just realised the q.no. 8 in chemistry's red spot past papers is incorrect so the answer also ought to be incorrect. so please sum1 tell me what would be the answer to
Q. ethane has structure as shown
H H
I I
H-C-C-H
I I
H H
i.e C2H6
how many of the electrons in a ethane C2H6 are not involved in bnding?
A)0
B)2
C)4
D)8
plz sum1 help me out a.s.a.p.
Click to expand...

A !
 
daredevil

daredevil

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faira said:
I just realised the q.no. 8 in chemistry's red spot past papers is incorrect so the answer also ought to be incorrect. so please sum1 tell me what would be the answer to
Q. ethane has structure as shown
H H
I I
H-C-C-H
I I
H H
i.e C2H6
how many of the electrons in a ethane C2H6 are not involved in bnding?
A)0
B)2
C)4
D)8
plz sum1 help me out a.s.a.p.
Click to expand...
according to me the answer is A [ 0 ]
 
daredevil

daredevil

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faira said:
how is it A please explain.
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draw the structure and u'll know that all hydrogen electrons are bonding bcz hydrogen has only one electron each and if its invlved it need to be bonded by that electron. and each carbon is bonded with four single bonds (1 with the other carbon and 3 with hydrogen atoms) got it >??
 
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