• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Biology; Chemistry; Physics: Post your doubts here!

Messages
212
Reaction score
675
Points
103
Yar why are you guys confusing different concepts?
The displayed and the structural formula of an organic compound is same.. BUTTT.. The displayed and the structural formula of isomers of a compound are different.
The q sourov just posted shows two ISOMERS. You can count the carbon and the hydrogen atoms. However, their structure is different as they are arranged differently in their displayed formulaes.
firstly, dont get angry
you said, "The displayed and the structural formula of an organic compound is same"...may i ask what is the structural, displayed and molecular formula of butane..
and u said, "However, their structure is different as they are arranged differently in their displayed formulaes."....what ?:confused:
 
Messages
2,797
Reaction score
2,035
Points
273
Yar why are you guys confusing different concepts?
The displayed and the structural formula of an organic compound is same.. BUTTT.. The displayed and the structural formula of isomers of a compound are different.
The q sourov just posted shows two ISOMERS. You can count the carbon and the hydrogen atoms. However, their structure is different as they are arranged differently in their displayed formulaes.
Structural Formula is the one shown, it is written in my book as well that structural formula can be displayed by both drawing and writing, but the latter is not common now, it was used in the old days. It is the condensed formula. Now, we use diagram representations of these. You can check from online sources if you want.
 
Messages
2,797
Reaction score
2,035
Points
273
Just copying what the examiner report has to say about that structural formula question

"
In a fully displayed structural formula, all the bonds between the atoms are shown. The bond between the O and the H in option D was missing and the correct answer was
A"
Guess i was right in the start
Well, I still believe CIE is mad. In their OWN questions they show structural formulas having OH not O-H and its in their books as well. Now, they expect students, in all that tension, to figure out these small details, I hate them! :mad:
 
Messages
1,258
Reaction score
1,397
Points
173
Messages
212
Reaction score
675
Points
103
Messages
98
Reaction score
25
Points
28
firstly, dont get angry
you said, "The displayed and the structural formula of an organic compound is same"...may i ask what is the structural, displayed and molecular formula of butane..
and u said, "However, their structure is different as they are arranged differently in their displayed formulaes."....what ?:confused:
I am posting my notes regarding formula of butane. You will see what I mean.
"However, their structure is different as they are arranged differently in their displayed formulaes." THIS IS FOR ISOMERS.
 
Messages
2,797
Reaction score
2,035
Points
273
I am posting my notes regarding formula of butane. You will see what I mean.
"However, their structure is different as they are arranged differently in their displayed formulaes." THIS IS FOR ISOMERS.
Displayed formulas are a type of structural formula. So are condensed formulas.
 
Messages
478
Reaction score
143
Points
53
k here is the explaination.

40g of Ca = 1 mole. So it would react with two moles of water that is 36g. The rest of the water 100-36 = 64g is still left in the solution

now on the product side, 1 mole of Ca(OH)2 is formed. We can ignore the H2 as it is lost as gas. So mass of Ca(OH)2 is 74g
So, 64 + 74 = 138g :)

Can u tell me why 2 moles will react?
 
Messages
2,797
Reaction score
2,035
Points
273
the mole of Ca is 1 but that of water is 5.6..so Ca is limiting agent (or water in excess)
and for mole ratio, always take the limiting agents mole:)
I don't know why use guys use 'limiting agent', it feels so odd (I know it's correct) since I've read 'in excess' from the beginning. :LOL:
 
Messages
1,258
Reaction score
1,397
Points
173
Difference in galvanising and sacrificial protection
galvanizing is to coat the whole Iron surface with Zinc so that the iron does not come in contact with water and air

In sacrifical protection, a more reactive metal is just attached to the Iron, so that it reacts first with the water and air, and corrodes in place of the Iron
 
Messages
1,764
Reaction score
3,472
Points
273
I don't know why use guys use 'limiting agent', it feels so odd (I know it's correct) since I've read 'in excess' from the beginning. :LOL:
same here i was like WHAT as i did not know what limiting factor meant
well i know what limiting factor is but i did not know here
 
Top