Chemistry doubt

[BishoyGamil]

http://www.xtremepapers.me/CIE/Cambridg ... 5_qp_3.pdf
Question 2 i, ii, iii :%)
Thanks in advance

 

[BishoyGamil]

Also, http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf
Question 4 b ii

 

[BishoyGamil]

Also, http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf
Question 4 iv

 

[BishoyGamil]

Also, http://www.xtremepapers.me/CIE/Cambridg ... 6_qp_3.pdf
question 6 c i . I cant solve the oxidant question

 

[xIshtar]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_w05_qp_3.pdf
Question 2 i, ii, iii :%)
Thanks in advance

2. a) i) In the region D to E, is boiling.
ii) The region B to C would be at a higher temperature range, as there would no longer be a fixed temperature.
iii) As no further state changes can occur, the line would continue the same way as E to F.

Also, http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf
Question 4 b ii

4.b) ii) If Iron (ii) was used, the valency would be 2+ rather than 3+, meaning that only two thirds of the volume of sodium hydroxide would be needed, so it would produce the same height precipitate at 8cm^3 of sodium hydroxide.

Also, http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf
Question 4 iv

4.iv) Silver, the only one which is below it in the reactivity series, as the more reactive metal loses the electrons to become a charged ion, which is the process of oxidation in terms of electron loss.

Also, http://www.xtremepapers.me/CIE/Cambridg ... 6_qp_3.pdf
question 6 c i . I cant solve the oxidant question

The reductant is the one which itself is oxidised, which causes the reduction of another substance. The oxidant itself is reduced, but it causes the electron loss of another substance.

With that taken into account, the Hydrogen itself is reduced, and thus itself is the oxidant. As for the reductant, the zinc electrode becomes thinner, meaning that it is becoming ions, which means that it is being oxidised, and thus it is the reductant.

 

[JmCullen]

2.a.ii) it's lower temperature. because there is impurity..

 

[xIshtar]

Apologies I was thinking of the temperature range, meaning it will be of a larger one rather than a fixed temperature I'll change my post

 

[BishoyGamil]

Thanks a bunch but would u mind to tolerate my sutipidity

The reductant is the one which itself is oxidised, which causes the reduction of another substance. The oxidant itself is reduced, but it causes the electron loss of another substance.

I undersatnad that

With that taken into account, the Hydrogen itself is reduced, and thus itself is the oxidant. As for the reductant, the zinc electrode becomes thinner, meaning that it is becoming ions, which means that it is being oxidised, and thus it is the reductant.

but i cant understand that because i duuno what really happens in the cell i mean what is oxidise or what is reduced if you explain which become ions and what elemnt will be reduced and so on in that example . Thanks for you help

 

[xIshtar]

Thanks a bunch but would u mind to tolerate my sutipidity

The reductant is the one which itself is oxidised, which causes the reduction of another substance. The oxidant itself is reduced, but it causes the electron loss of another substance.

I undersatnad that

With that taken into account, the Hydrogen itself is reduced, and thus itself is the oxidant. As for the reductant, the zinc electrode becomes thinner, meaning that it is becoming ions, which means that it is being oxidised, and thus it is the reductant.

but i cant understand that because i duuno what really happens in the cell i mean what is oxidise or what is reduced if you explain which become ions and what elemnt will be reduced and so on in that example . Thanks for you help

The hydrogen is reduced as it changes from a H+ ion into a H2 gas. Meaning, electrons were gained.
The zinc changes into zinc ions in the solution as it gets smaller. This means it changes from Zn to Zn2+, meaning that it loses electrons, and thus it is oxidised.