Physics, Chemistry and Biology: Post your doubts here!

[Yousif Mukkhtar]

Guys in here: question 4 c)
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_qp_31.pdf

Please check the attached file, and tell me which skeletal arrangement is correct.

 

[Dashexdan]

Guys in here: question 4 c)
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w09_qp_31.pdf

Please check the attached file, and tell me which skeletal arrangement is correct.

u must link S to C not H

 

[Yousif Mukkhtar]

u must link S to C not H

Yeah I know that, I got my whole diagram correct. It is only the structure. Should it be horiztonal or slanting/

 

[Dashexdan]

Yeah I know that, I got my whole diagram correct. It is only the structure. Should it be horiztonal or slanting/

any way

 

[Yousif Mukkhtar]

any way

Thanks.

 

[Penalopi]

Question: When fat is hyrdrolysed by boiling with NaOH what are the products?

 

[Yousif Mukkhtar]

Question: When fat is hyrdrolysed by boiling with NaOH what are the products?

Soaps (salts of the fatty acids) and glycerol.

 

[Yousif Mukkhtar]

Guys for bonding, does it matter if the circles are in the same size. I know hydrogen is always smaller, but what about other elements?

 

[Penalopi]

Guys for bonding, does it matter if the circles are in the same size. I know hydrogen is always smaller, but what about other elements?

no it doesn't as long as you label them!

 

[Penalopi]

Soaps (salts of the fatty acids) and glycerol.

thanks!

 

[Yousif Mukkhtar]

no it doesn't as long as you label them!

Thanks a ton!

 

[Penalopi]

anytime..now we'r even

 

[gelato]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s06_qp_6.pdf
3 v) & vi)
Can anyone draw them please? I want to check if mine's correct

 

[thats_me]

how do u noe dat its endo or exo? in d qn, its 200 degree C, so i said exo, n it was wrong..

the one that takes in more heat is endo ,the one that takes less is exo
in other cases if they state that for eg: backward reaction is endo n ask for forward , so forward will be opp i.e exo

 

[mahmouds]

Guys should the scale of any graph in physics start with zero pr it can start from any number .????

 

[thats_me]

Guys should the scale of any graph in physics start with zero pr it can start from any number .????

its compulsory to start with zero only if its specified in the question.... If not thn it's up to u,,You can start from any number as long as you break the graph...

 

[mahmouds]

its compulsory to start with zero only if its specified in the question.... If not thn it's up to u,,You can start from any number as long as you break the graph...

Thank you !!!
Can you kindly help me with some questions i had posted before !??

 

[sma786]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w07_qp_3.pdf
last question , last part (iii) how to fnd out the CO2 volume?

 

[Dashexdan]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w07_qp_3.pdf
last question , last part (iii) how to fnd out the CO2 volume?

as u see HCL is the limiting agent so moles of HCL is 0.005 but the ration between HCL and CO2 is not equal in the equation, the ratio is 2:1
so to find out the moles of CO2 formed we divide the moles of HCL by 2 thats = 0.0025
then we just use the formula for gases i.e. moles=volume of gas in dm3/24,,,,so we hav moles and we hav 24dm3
so substitute them and multiply 24*0..0025=0.06dm3

 

[Tekno-M]

For question 4b,
I think if you must view the pin from down. This came as a question but the other way round as in they asked why do you need to view the pin from down, in one of the recent papers.