Physics, Chemistry and Biology: Post your doubts here!

[AAnsarii]

Whats the formula for a nitrite?! and thanks dude

NO2-

 

[Maz]

please sby ans dis i need 2 go 2 sleep..

The molecular formula is C4H4O4.
And the question says that one mole is dibasic.
THerefore,

HOOC-C=C-COOH
| |
H H
There should be in total 4 of each.But, since it is dibasic we make 2 molecules.

 

[Maz]

ok we talked about breaking bonds and forming bonds
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_33.pdf
check question 7 b(iii)

it talks about bond energy
help?

You now the question itself says what is bond energy.
"Bond energy is the amount of energy, in kJ, which must be supplied to break one
mole of the bond."
This is present in the question itself. '_'

 

[AAnsarii]

ok we talked about breaking bonds and forming bonds
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_33.pdf
check question 7 b(iii)

it talks about bond energy
help?

basically, its d sm.
C=C is broken, so +610. H-H is broken, so +436. add them, u get 1046.
2C-H are made, so -415*2= -830. then a C-C bond is made, so -346, which gives u -1176.
now u say dat more e is released dan absorbed, n blabla

 

[AAnsarii]

The molecular formula is C4H4O4.
And the question says that one mole is dibasic.
THerefore,

HOOC-C=C-COOH
| |
H H
There should be in total 4 of each.But, since it is dibasic we make 2 molecules.

Jazakallah, but 2 molecules of wat?

 

[imperial]

You now the question itself says what is bond energy.
"Bond energy is the amount of energy, in kJ, which must be supplied to break one
mole of the bond."
This is present in the question itself. '_'

i meant how to relate it with exothermic and endothermic

basically, its d sm.
C=C is broken, so +610. H-H is broken, so +436. add them, u get 1046.
2C-H are made, so -415*2= -830. then a C-C bond is made, so -346, which gives u -1176.
now u say dat more e is released dan absorbed, n blabla

ty

 

[AAnsarii]

i meant how to relate it with exothermic and endothermic



ty

amount of energy supplied 2 break d bond that makes it endothermic,rite?

.

 

[Maz]

Okay, then assalaamu alaikum for now.
I really need my sleep.
Pray for an A* everyone. Insha Allah.

 

[imperial]

LOVE YOU GUYS, THANKS FOR ALL THE EFFORT, AND I HOPE YOU HELP AS MUCH CLUELESS PEOPLE LIKE ME AS MUCH AS YOU CAN, YOU ARE DOING A GOOD THING TO THEM, AND IS SELF BENEFICIAL TOO, GOOD LUCK WITH THE EXAM, AND FOR THE FUTURE ONES.

<3<3<3

SOMEONE GONNA SLEEP, AND THATS ME

 

[Billy123]

http://www.xtremepapers.com/community/threads/chemistry-help-asap.16995/

Help me affa

 

[Saed]

http://www.xtremepapers.com/community/threads/chemistry-leaked-papers-or-any-question.17000/

 

[angel G]

Can anyone explain me Le Chatelier's principle ? please !!

 

[thats_me]

Can anyone explain me Le Chatelier's principle ? please !!

pg 54
http://www.xtremepapers.com/communi...y-revision-guide-according-to-syllabus.16647/

 

[angel G]

pg 54
http://www.xtremepapers.com/communi...y-revision-guide-according-to-syllabus.16647/

Thank you !!

 

[gelato]

How to do 3 a) i) and ii) ?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_32.pdf
I don't think I'm going to do well in this exam

 

[secret lover]

how to solve qs 5 (d)..???http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w06_qp_3.pdf
plz very IMPORTANT!!

 

[MERIHAN]

what is redox reaction ???????????

 

[NIM]

what is redox reaction ???????????

Redox is same like oxidation and reduction reaction. it involves the transfer of two types of chemical species.

 

[MERIHAN]

Redox is same like oxidation and reduction reaction. it involves the transfer of two types of chemical species.

means in the reaction both oxidation and reduction should take place ????????????????

 

[MERIHAN]

c

Redox is same like oxidation and reduction reaction. it involves the transfer of two types of chemical species.

can u give example plz thanks in advance