HELP HELP!

[Lost_Life]

J

Aww ;D Thank Youh! Urgh.. I Did A Mistake :/
I was correct upto this level

Mole ---------------------4/4------------ 4/20.2
----------------------------1 ----------------0.2

But i forgot to divide by smallest. >.<
Hehe

Btw, it is the question you asked >> June 2010 Unit 1 question 8.
What is that electron question. I May Help ;D

Jan 2010 q 8

 

[tom850]

J
Jan 2010 q 8

Your Mistake ! Lemme Check it

 

[aniekan]

Your Mistake ! Lemme Check it

THE ANSWER IS C

WHY BECAUSE YOU ARE STARTING FROM THE LEAST.

 

[tom850]

J
Jan 2010 q 8

Aww I found the answer ;D It is D
You Know why? Because...the question asks about first five electrons.
Aluminium has atomic number 13 and therefore it consists of 13 electrons. The last electron is in 3p orbital !
The next two electrons are in 3s orbital. and the remaining 2 electrons are removed from 2p orbital.

Hence, the answer is D: 3p 3s 3s 2p 2p

 

[Lost_Life]

Aww I found the answer ;D It is D
You Know why? Because...the question asks about first five electrons.
Aluminium has atomic number 13 and therefore it consists of 13 electrons. The last electron is in 3p orbital !
The next two electrons are in 3s orbital. and the remaining 2 electrons are removed from 2p orbital.

Hence, the answer is D: 3p 3s 3s 2p 2p

got another one for ya

 

[tom850]

got another one for yaView attachment 20063

Aw just saw it. :/
You did a simple mistake there To balance the equation they have given octane as 2 moles.
1 mol .............. 114 g
2 mol .............. 228 g

So, 10 mol ......... 1140g which leads to 1.14kg.
The answer is B.

 

[Lost_Life]

should we know about tetrachloroethane? i know how to draw chloroethane, but the tetra..scared me.

 

[tom850]

should we know about tetrachloroethane? i know how to draw chloroethane, but the tetra..scared me.

Haha scared..
I think the questions may come about it. Reactions of alkanes with chlorine is an important part of organic chemistry.
I know how to draw tetrachloromethane:/

In tetrachloroethane the molecular formula is C2H2Cl4 ?
The Structural formula is CHCl2CHCl2

We have to know the displayed formula too. Can you draw now

 

[Lost_Life]

Haha scared..
I think the questions may come about it. Reactions of alkanes with chlorine is an important part of organic chemistry.
I know how to draw tetrachloromethane:/

In tetrachloroethane the molecular formula is C2H2Cl4 ?
The Structural formula is CHCl2CHCl2

We have to know the displayed formula too. Can you draw now

i knew how to draw it, but i got a mini heart attack,. doesn't show up in a lot of questions..

 

[tom850]

i knew how to draw it, but i got a mini heart attack,. doesn't show up in a lot of questions..

Aw mini attack.. But we have to prepare. It may come in any question..

how far have you gone in past papers now. Im yet doing 3b papers..

 

[aniekan]

i knew how to draw it, but i got a mini heart attack,. doesn't show up in a lot of questions..

lol Just prepare but i doubt you will find it ....Obviously you will find questions in : Ionization energy , Bonding , Enthalpy and the 50% Organic chemistry Moles is the least topic

 

[Lost_Life]

lol Just prepare but i doubt you will find it ....Obviously you will find questions in : Ionization energy , Bonding , Enthalpy and the 50% Organic chemistry Moles is the least topic

some percentage yields, atom economies, Hazards and risks...

 

[Lost_Life]

Aw mini attack.. But we have to prepare. It may come in any question..

how far have you gone in past papers now. Im yet doing 3b papers..

im stopping till June 2011 for today. I'll revise bio, and math for the rest of the day.

 

[aniekan]

some percentage yields, atom economies, Hazards and risks...

Yeah but not really toO hard to guess answers regarding that

 

[Lost_Life]

Yeah but not really to hard to guess answers regarding that

nah, i find them simple

 

[Lost_Life]

 

[tom850]

View attachment 20096

Aw That Q.. :/ I'm yet doing 2010:'( But below is the answer for that question:/
Acceptable Answers: There are 4 marks
First & second marks stand alone
1. Pipette/burette / measuring
cylinder / balance to transfer (a
known amount of) (water) (1)
2. to (expanded) polystyrene cup /
calorimeter / any insulated
container allow coffee / plastic
cup (1)
Third & fourth marks only awarded
if correct chemicals and procedure
used
3. add solid and stir (allow mix or
shake) mixture (1)
4. measure initial and final
temperature
allow temperature change (1)

 

[Lost_Life]

Aw That Q.. :/ I'm yet doing 2010:'( But below is the answer for that question:/
Acceptable Answers: There are 4 marks
First & second marks stand alone
1. Pipette/burette / measuring
cylinder / balance to transfer (a
known amount of) (water) (1)
2. to (expanded) polystyrene cup /
calorimeter / any insulated
container allow coffee / plastic
cup (1)
Third & fourth marks only awarded
if correct chemicals and procedure
used
3. add solid and stir (allow mix or
shake) mixture (1)
4. measure initial and final
temperature
allow temperature change (1)

ah..the mark scheme.. i checked it out too. but i didn't know how..??

 

[Mewan95]

Can someone explain percentage error calculation? :/

 

[Lost_Life]

:O

Aw That Q.. :/ I'm yet doing 2010:'( But below is the answer for that question:/
Acceptable Answers: There are 4 marks
First & second marks stand alone
1. Pipette/burette / measuring
cylinder / balance to transfer (a
known amount of) (water) (1)
2. to (expanded) polystyrene cup /
calorimeter / any insulated
container allow coffee / plastic
cup (1)
Third & fourth marks only awarded
if correct chemicals and procedure
used
3. add solid and stir (allow mix or
shake) mixture (1)
4. measure initial and final
temperature
allow temperature change (1)

:O is it by using E=mcdelatT :O OMGG I GET IT