IGCSE CHEMISTRY EXAM 2025/2026 QUESTIONS AND ANSWERS 100% PASS

IGCSE CHEMISTRY EXAM 2025/2026
QUESTIONS AND ANSWERS 100% PASS




1.30 recall the ? of common ? in this specification
K?
Na ?
Li ?
H?
Mg ??
Ca ??
Al ??
Cl?
Br?
I?
F?
OH?
NO??
SO4 ??

CO3 ?? - ANS 1.30 recall the CHARGES of common IONS in this specification
K+
Na +
Li +

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,H+
Mg 2+
Ca 2+
Al 3+
Cl-
Br-
I-
F-
OH-
NO3-
SO4 2-
CO3 2-


1.56 recall that one ? represents one ? of ?

One ? is ? ?. That is the amount of ? in ? ? of ?. - ANS 1.56 recall that one faraday represents
one mole of electrons
One FARADAY is 96500 COULOMBS. That is the amount of COULOMBS in ONE MOLE of
ELECTRONS.


1.57 calculate the amounts of the ? of the ? of ? ? and ? solutions
One ? is ? ?. It is also one ? of ?.
If ? of 0.2 ? is passed through copper(ll) sulphate for two ?, how much ? do you get?


1) Write out the ? equation
(Cu2+) + 2e > Cu
2) Work out ? of electrons flowing
?= ? x time
?= ?T

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,? is 2x60x60 (times 60 makes ?, times 60 again makes it ?)
Q= 0.2 x 7200= 1440 ?
Convert ? into ? of ?
?= C/?
?= 1440/96500
?= 0.015
Work out ? factor
(Cu2+) + 2e > Cu
For every ? moles of electrons, there will be ? Cu
Sf= Moles of ?/ moles of ?
Sf= 1/2
Sf= a half
3) Work out ? of product using ? ?
so we do the ? of electrons times the ? ?
0.015x1/2= 0.0075 Moles of Cu
Convert ? into ?
Moles x Mr

0.0075 x 63.5= 0.48g of copper - ANS 1.57 calculate the amounts of the products of the
electrolysis of molten salts and aqueous solutions
One faraday is 96500 coulombs. It is also one mole of electrons.
If current of 0.2 Apms is passed through copper(ll) sulphate for tow hours, how much copper do
you get?


Write out the HALF equation
Cu2+ + 2e > Cu
Work out COULOMBS of electrons flowing
COULOMBS= CURRENT x time
Q= IT

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, TIME is 2x60x60 (times 60 makes MINUTES, times 60 again makes it SECONDS)
Q= 0.2 x 7200= 1440 COULOMBS
Convert C into MOLES of ELECTRONS
MOLES= C/FARADAY
MOLES= 1440/96500
MOLES= 0.015
Work out SCALE factor
Cu2+ + 2e > Cu
For every TWO moles of electrons, there will be ONE Cu
Sf= Moles of PRODUCT/ moles of ELECTRONS
Sf= 1/2
Sf= a half
Work out MOLES of product using SCALE FACTOR
so we do the MOLES of electrons times the SCALE FACTOR
0.015x1/2= 0.0075 Moles of Cu
Convert MOLES into MASS
Moles x Mr
0.0075 x 63.5= 0.48g of copper


1.55 write ionic half-equations representing the reactions at the electrodes during electrolysis
At the ? ?, electrons will be ?: to show this we write the ? electrons as ?:
2Br- > Br2 + 2e-
Make sure the ? are ? on both sides: 1- > 1-.


At the ? ?, electrons will be ? so we write them as ?:
2H+ + 2e- > H2




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