Biology; Chemistry; Physics: Post your doubts here!

[thementor]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s11_qp_22.pdf
Q9 a(i)
The first two sections of the graph were easy.....What is confusing me is the third section: "He opens his parachute at t=20s and decelerates until t=25s.......
In books it has been shown that a curved line is drawn after the parachute is opened until terminal velocity is reac

 

[nidz]

What does the term 'reflux' mean? Found it in a marking schem of Chemistry :/

 

[nidz]

View attachment 23999

Do you know if we should make the structure of propene like http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene.gif
Or http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene_2.gif

 

[papajohn]

What does the term 'reflux' mean? Found it in a marking schem of Chemistry :/

Never heard of that before..

 

[Sijal Mirza]

P.S. I do not own any of the notes.

thank you sooo much

 

[Saad Mughal]

Do you know if we should make the structure of propene like http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene.gif
Or http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene_2.gif

You can make both. The propene is the unbranched structure of the compound whereas the propene 2 is the branced structure of the compound. They are isomers.

 

[Saad Mughal]

thank you sooo much

 

[papajohn]

Check this out..

 

[Sijal Mirza]

o

omgg they are veryy gooood :O THANK YOU SOOO MUCH!!!! :'D

 

[Saad Mughal]

What does the term 'reflux' mean? Found it in a marking schem of Chemistry :/

Reflux is like recollection, it is used in distillation (or when boiling liquids), the vapors of the liquid are condensed and returned to the solution (this is called reflux), it prevents loss of any liquid from the container.

 

[papajohn]

Reflux is like recollection, it is used in distillation (or when boiling liquids), the vapors of the liquid are condensed and returned to the solution (this is called reflux), it prevents loss of any liquid from the container.

Mr Know it all!

 

[Saad Mughal]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s11_qp_22.pdf
Q9 a(i)
The first two sections of the graph were easy.....What is confusing me is the third section: "He opens his parachute at t=20s and decelerates until t=25s.......
In books it has been shown that a curved line is drawn after the parachute is opened until terminal velocity is reac

This is what your graph should look like.

 

[Saad Mughal]

Mr Know it all!

 

[Suchal Riaz]

What does the term 'reflux' mean? Found it in a marking schem of Chemistry :/

u must be talking about reflux condenser. i heard it several time in class. it is used in organic reactions when u r afraid that the volatile liquid such as ethanol will evaporate during reaction as it condenses it back.

 

[Suchal Riaz]

Im amazed a bit You did it the alevel way, Congratz you actually covered almost whole of A level physics vectors
And by the way make sure if u try this method in exam u get credit because CIE never liked when people did extra stuff more than required but anyways ask your sir ! But i think you know both methods and this method of yours helps a lot in Add maths,those having troubles abt how he broke the vector into pieces think about the i and j vectors from add maths or just think that vector which is given can be broken into two parts one a horizontal and the other vertical these are called vector components,but plz dont get disappointed or sad just because he knows the method and you dont use the parallelogram law or head to tail rule the most easiest one for O levels and added advantage of using in A level too later on so its very good if u know these rules and not those components !!

i leanred about vectors in MIT's first year physics course. at that time i had not done vectors in add maths but i had no difficulty in any vector operation.

 

[usama321]

You can make both. The propene is the unbranched structure of the compound whereas the propene 2 is the branced structure of the compound. They are isomers.

actually they are not isomers. They are the same, look carefully, in the second one, he just did not make the lines between the bonds, it is not branched.

 

[usama321]

Do you know if we should make the structure of propene like http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene.gif
Or http://www.bbc.co.uk/bitesize/standard/chemistry/images/propene_2.gif

actually there are the same thing, not isomers. If you want to make an isomer of propene, move the double bond between the second two carbon atoms

 

[Saad Mughal]

actually they are not isomers. They are the same, look carefully, in the second one, he just did not make the lines between the bonds, it is not branched.

Look again,
The CH3 is branched upwards not sideways, it means that the carbon and 3 hydrogen atoms are bonded upwards.
P.S. The drawing is filthy. I'm no good at this paint business.

 

[Suchal Riaz]

MJE NE SAMJH AAYA

ask ur teacher about component vectors.
you better understand Haris Bin Zahid method i like it more as it is simpler for an ordinary o level physics student. it was actually meant to be done that way.

 

[usama321]

Look again,
The CH3 is branched upwards not sideways, it means that the carbon and 3 hydrogen atoms are bonded upwards.
P.S. The drawing is filthy. I'm no good at this paint business.
View attachment 24022

branch only means when you are extending a branch from in between a carbon chain like this


What you did was just bend the last carbon bonding, which is not a branch