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)
You have to use trial and error.View attachment 60309
plzzzz helppppppppppp
then why they have given the pressure and temperatureYou have to use trial and error.
Option A :
The equation: 2Ca + O2 --> 2CaO
Moles of oxygen : 0.3/24 = 1/80
Moles of calcium that will react : 2 × 1/80 = 1/40 (since 2 moles of calcium react with one mole of oxygen.
Moles of metal given in question : 1.15/40 = 23/800
The moles given and the moles that react aren't equal so this is incorrect
Now use this way for all of them. I'll do it for the correct option D
Option D :
The equation: 4Na + O2 --> 2Na2O
Moles of oxygen : 1/80
Moles of sodium that will react : 4 × 1/80 = 1/20
Moles of metal given in question: 1.15/23 = 1/20
They are the same thus D is the ans.
To let u know that the reaction is carried out at room temperature and pressure.then why they have given the pressure and temperature
did you see the mark scheme?View attachment 60328
Part (ii). I was wondering is it acceptable if the reagent is some nitrate salt of a metal more reactive than Mg like KNO3 or NaNO3 so a double displacement reaction takes place.
I don't think it will work because nitric acid is a strong acid which neutralized MgO, on the other hand KNO3 is almost neutral and is moderately soluble in water. I doubt if it'll react at all and of course to be on the safe side, we'd better write what we already came across in our syllabusView attachment 60328
Part (ii). I was wondering is it acceptable if the reagent is some nitrate salt of a metal more reactive than Mg like KNO3 or NaNO3 so a double displacement reaction takes place.
Alrighty then. ThanksI don't think it will work because nitric acid is a strong acid which neutralized MgO, on the other hand KNO3 is almost neutral and is moderately soluble in water. I doubt if it'll react at all and of course to be on the safe side, we'd better write what we already came across in our syllabus
yep, they are alright! The main thing is The alkene should have a double bond in between, which you drew right, and the number of carbons should be same which is also okay...The ketone also has it's functional group all fine and carbon atoms too. It doesn't matter how much we rotate it, or draw it in which way, because it all means the same (remember, as long as we don't count it as another isomer, it's the same molecule)Ik I am asking silly questions but I just want to be on the safe side
The skeletal formula of 2-3 dimethyl but 2 ene and propanone are like this in the msView attachment 60329
This is how I drew themView attachment 60330 they're fine right?
its always better to use whatever is present in the mark scheme if u want to b on a safe sideDo I have to use skeletal formula in Paper 4? It seems like all the answers in the markscheme are standardised to use skeletal formula, but I am more comfortable with the displayed formula. I know sometimes they specify but do I have to use if its not specified in the question?
If it isn't specified in the question, you can use any as long as it is correct.Do I have to use skeletal formula in Paper 4? It seems like all the answers in the markscheme are standardised to use skeletal formula, but I am more comfortable with the displayed formula. I know sometimes they specify but do I have to use if its not specified in the question?
Where is your K2SO4 formed? I guess you should start writing the way mark scheme advises us cauz it's kinda confusingIs it fine of I write them as 2 separate reactions because that's how it is in the Cambridge book.View attachment 60334
This is how it is in the msView attachment 60335
Notice that before hydrolysis, we have total 5 alcohols, one primary alcohol, the one projecting upwards on top left, and the other 4 are all primary, because all of them are bonded to a carbon which, in turn, is bonded to another carbon.Anyone please explain?
View attachment 60340
For almost 10 years, the site XtremePapers has been trying very hard to serve its users.
However, we are now struggling to cover its operational costs due to unforeseen circumstances. If we helped you in any way, kindly contribute and be the part of this effort. No act of kindness, no matter how small, is ever wasted.
Click here to Donate Now