Edexcel IAL Chemistry (WCH06/01) Chemistry Laboratory Skills II - 10th May 2016

Hi all
couldnt find a thread on this so decided to create one hows prep?

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I have a question for calculating enthalpy changes when do we consider the mass of the solid added to the solution? when do we consider just the mass of the solution? and when do we consider the combined mass? In the equation Q= mc(deltaT)

(edited 7 years ago)

Reply 2

AlvlVictim

Bump

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Reply 3

AlvlVictim

Bumping again need help 😯😢

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Reply 4

AlvlVictim

Well no help yet I will attach an example question

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Reply 5

alevels2k17

Original post by Saad69

we only take the mass of the solution. if the other reactant added was a solid we do not consider it but if it was also a solution we add the solutions up (their volumes)
idk hope that was clear

Reply 6

AlvlVictim

Original post by pondsteps

we only take the mass of the solution. if the other reactant added was a solid we do not consider it but if it was also a solution we add the solutions up (their volumes)
idk hope that was clear

I got the first part saying that only solid masses are considered could u explain the 2nd part again about volumes

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Reply 7

alevels2k17

Original post by Saad69

I got the first part saying that only solid masses are considered could u explain the 2nd part again about volumes

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wait no u got me wrong! i meant when in the rule it is m*c* delta T. so for the mass in the rule we use the volume of the solution and put it as it is for the mass since we assume that the density is 1.. whenever given in the question mass of solid, forget about it in the rule since we only consider solutions..
eg. 5g of zinc added to 10cm3 of sodium hydroxide
the mass used in mcdeltaT is 10

10cm3 of sodium hydroxide added to 50 cm3 of hcl
the mass used here is 60 cm3

Reply 8

-Akuma-

We consider the combined mass when we're adding something aqueous to another anquous reagent. Or else we just consider the mass or the aqueous reagent, since it has the most significant heat capacity ( absorb most of the heat)

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Reply 9

-Akuma-

:3 so how's prep everyone? Chem's pretty good for me but physics is giving me a hard time

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Reply 10

alevels2k17

[QUOTE="-Akuma-;64672505"]:3 so how's prep everyone? Chem's pretty good for me but physics is giving me a hard time

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Same chem is going well, but biooo ugh I hate it. My exam is today :frown:

Reply 11

-Akuma-

Good luck with bio!

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Reply 12

AlvlVictim

Good luck to you :smile:

(edited 7 years ago)

Reply 13

Nethmioysters

Original post by -Akuma-

:3 so how's prep everyone? Chem's pretty good for me but physics is giving me a hard time

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same here! physics is the worst! :frown:

Reply 14

AlvlVictim

Original post by Nethmioysters

same here! physics is the worst! :frown:

physics unit 3 is not that tough for me ask me any doubts u may have from it :smile:

Reply 15

Nethmioysters

Original post by Saad69

physics unit 3 is not that tough for me ask me any doubts u may have from it :smile:

thanks! ill ask you, when i come across some of my doubts!

Reply 16

-Akuma-

Um can anybody tell me why we add saturated NaCl solution during purification of cyclohexene, which is made from cyclohexanol?

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