IGCSE CHEMISTRY SOLVED past paper 0620/42/F/M/22

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IGCSE CHEMISTRY SOLVED past paper 0620/42/F/M/22 - Feb/March 2022 Paper 42

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Dr. Mona Seif

Күн бұрын

Пікірлер: 22

@maylight27 4 ай бұрын

Hi Dr Mona, your video really helped me when solving past papers. Just a question, in qs 3 (c) (ii) how did you know the order of the product, like how do you know it is HNCO, and not CONH or NHCO.. Is there a specific criteria I have to follow to know the exact order?

@DrMonaSeif 4 ай бұрын

U have to arrange them according to how many bonds each atom can make . Ex, Carbon can make 4 bonds 2 with oxygen and 2 with nitrogen So carbon has to be in the middle between O and N

@maylight27 4 ай бұрын

When you say bonds, do you mean the valence electrons, going from highest to lowest?

@DrMonaSeif 4 ай бұрын

I mean how many electrons are needed to complete it's outer shell to 8 electrons. And as for hydrogen only 2 electrons are needed for a complete outer shell.

@maylight27 4 ай бұрын

@@DrMonaSeif oh I kind of get it in now. Appreciate, thanks!

@mohannadmohamadhasseb7618 Жыл бұрын

Thank you soo much it really helps me ❤❤

@forgottenkitten81 2 жыл бұрын

Thank you sooo much for your efforts, the explanation is quite clear and fairly detailed.

@gamesause6949 2 жыл бұрын

Thank you this was really helpful

@raidm1838 4 ай бұрын

for Q6dii) the answer is just ethyl butanoate and butyl ethanoate in the mark scheme, is it ok if i write smth else like methyl pentanoate

@xdSloshy 3 ай бұрын

Yes

@jomanaeldod399 3 ай бұрын

I dont quite understand why did we choose a metal below iron in q4 bii

@aayan3939 3 ай бұрын

the bigger the gap between the two metals in the reactivity series, the more voltage is obtained

@georgereda1933 2 жыл бұрын

where can I find question paper?

@DrMonaSeif 2 жыл бұрын

Write ur email, and I will send it to you.

@yumna7717 Жыл бұрын

i didn't get Q4 part e{ii}

@DrMonaSeif Жыл бұрын

In case of electrolysis of molten NaCl we only have Na +ions And Cl- ions So Sodium metal will discharge at the cathode and chlorine gas will discharge at the anode And the electrolyte is used up . So sodium metal is the different substance formed in case of molten NaCl

@yumna7717 Жыл бұрын

@@DrMonaSeif sodium is different because it is a metal and chlorine is a gas?

@DrMonaSeif Жыл бұрын

It is the different product formed In case of molten NaCl only But Cl2 gas is formed in both cases (Molten and concentrated NaCl solution)

@yumna7717 Жыл бұрын

@@DrMonaSeif Ohhhh now i get it thank youuu!!! :)))

@maylight27 4 ай бұрын

Hi Dr. Mona! Thanks for the video, it really helped. I would really appreciate if you could explain how you know the product in question 3 (c)(ii) is HNCO and not, basically how did you know the order of the compound? Thanks