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Asslamu Alikum Wa Rahmatullah Wa Barakatoho... scouserlfc
2 Use of the Data Booklet is relevant to this question.....(9701/1/O/N/03)
A garden fertiliser is said to have a phosphorus content of 30.0% ‘P2O5 soluble in water’.
What is the percentage by mass of phosphorus in the fertiliser?
A 6.55%
B 13.1 %
C 26.2%
D 30.0%
Why is the Answer B ?
5 The table gives the successive ionisation energies for an element X.
............................................1st... 2nd.... 3rd ....4th...... 5th.... .6th
ionisation energy / kJ mol–1.... 950. 1800 .2700.. 4800 ....6000...12300
What could be the formula of the chloride of X?
A XCl
B XCl2
C XCl3
D XCl4
Why is the answer C?
Wallaikum As Salam !
Its quite simple actually !
it tells u first that the fertilizer has 30% P2O5 content so it means actually u have 100g of fertilizer of which 30g is P2O5
so just find the mass of phosphorus content using simple ratio ,
142(Mr of P2O5) ----- 30
62 ------ x
x=13.1%
there is a big jump in iE values from 3 to 4 abt 2000 KJ but this isnt really enuf to tell us that the new shell starts here probably it shows the start of s subshell so now u can be assured that its from grp 5 now remember how hydrogen bonds with nitrogen and requires exactly 1 electron like Cl atoms and has a formula NH3 so Cl will have NCl3 (the use of atoms here is just for an example its not necessary its the real one )
I will be very thankful for help. I have a problem in question number 3(c)(iii) calculation part of 9701/02/M/J/04. I could not understand the marking scheme. Somebody please help me with a step by step procedure.
Use first the part i answer for 3c which is 0.05 now use the ratio of the equation as acid is in a ratio of 1:2 with the ammonia half the moles of the ammonia and u have the moles of H2SO4 which is 0.025 now use the conc. of H2SO4 and the moles to get the volume of H2SO4 in dm^3 and convert it into cm^3 by multiplying with 1000 .