AS Chemistry- helping each other out!

Reply 1920

I'm redoing my ISA to try get a better mark, Is this the AQA one with the milk of magnesia?

Yeah it is

Well done, just be careful what you say as it is against the rules to share specific details about practicals

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Oh i'll keep that in mind

Reply 1921

amino9

1

Original post by grapes12

I did my ISA today. It went really well. For anyone doing AQA and titrations I suggest you look at halides and the precipitates they form, group 2 metals and how to work out solubility

mine didnt :bawling:

Reply 1922

Connor_leigh

2

Yeah it is

I'll be sure to check this out (Y) Thanks a lot :biggrin:

Reply 1923

grapes12

8

Original post by amino9

mine didnt :bawling:

Sorry to hear. Is this your resit or do you still have that option? This was my resit, I got a C in my last one but the whole class got D's and E's so I decided to resit too. Missed an hour of philosophy so win win!

Reply 1924

Connor_leigh

2

mine didnt

Was this your second ISA? Or first?

Reply 1925

Connor_leigh

2

Original post by grapes12

Sorry to hear. Is this your resit or do you still have that option? This was my resit, I got a C in my last one but the whole class got D's and E's so I decided to resit too. Missed an hour of philosophy so win win!

Yeah majority of my class flunked out on this one too. I think i managed to just scrape a B which isn't what i wanted. Hopefully this one will be a little easier :smile:

Reply 1926

grapes12

8

Original post by Connor_leigh

Yeah majority of my class flunked out on this one too. I think i managed to just scrape a B which isn't what i wanted. Hopefully this one will be a little easier :smile:

Well done! I got my biology ISA back today and it was a D! The day I took it I had a rough fall out with my boyfriend and I let it get in the way of my grade, so I have to resit that one too! Learn from my mistakes guys, stay single until AFTER exams! Lol

Reply 1927

Connor_leigh

2

Original post by grapes12

Well done! I got my biology ISA back today and it was a D! The day I took it I had a rough fall out with my boyfriend and I let it get in the way of my grade, so I have to resit that one too! Learn from my mistakes guys, stay single until AFTER exams! Lol

Haven't really had a choice of that haha. I messed up my biology isa too. It's my weakest subject, don't find it that enjoyable and my orthodontist always seems to book my appointments on a tuesday (I have double biology that day). When is your resit?

Reply 1928

grapes12

8

Original post by Connor_leigh

Haven't really had a choice of that haha. I messed up my biology isa too. It's my weakest subject, don't find it that enjoyable and my orthodontist always seems to book my appointments on a tuesday (I have double biology that day). When is your resit?

Its one of my weaker subjects too, no where near as bad as philosophy though! My resit will be next week. Not sure what its on though, my last one was about rubber tubing being models of blood vessels

Reply 1929

Connor_leigh

2

Original post by grapes12

Its one of my weaker subjects too, no where near as bad as philosophy though! My resit will be next week. Not sure what its on though, my last one was about rubber tubing being models of blood vessels

Yeah thats what my one was on aswell. What other lessons do you do? Any other ones with ISA's i can help with?

Reply 1930

Connor_leigh

2

'Boron trichloride is easily hydrolysed to form two different acids as shown in the following equation.
Bcl3 + 3h20 makes(can't do an arrow) H3BO3+3HCl.
Calculate the concentration in mol dm^-3 oh hydrochloric acid produced when 43,2g of boron trichloride are added to water to form 500cm^3 of solution. Give your answer to 3 significant figures'

I've checked a mark scheme and it's saying 43.2/117.3. Can anyone tell me where the 117.3 comes from please?

Reply 1931

samb1234

13

Original post by Connor_leigh

'Boron trichloride is easily hydrolysed to form two different acids as shown in the following equation.
Bcl3 + 3h20 makes(can't do an arrow) H3BO3+3HCl.
Calculate the concentration in mol dm^-3 oh hydrochloric acid produced when 43,2g of boron trichloride are added to water to form 500cm^3 of solution. Give your answer to 3 significant figures'

I've checked a mark scheme and it's saying 43.2/117.3. Can anyone tell me where the 117.3 comes from please?

Its the Mr of BCl3

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Reply 1932

Connor_leigh

2

Original post by samb1234

Its the Mr of BCl3

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Thanks! I used the proton number of boron.... My Mr calculation of BCl3 came out wrong. Thats why i was so confused :frown:

Reply 1933

Connor_leigh

2

Can someone also please explain why you times to moles of Hcl by 1000/500? Thanks in advance

Reply 1934

C0balt

16

Original post by Connor_leigh

Can someone also please explain why you times to moles of Hcl by 1000/500? Thanks in advance

What's the question

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Reply 1935

Connor_leigh

2

(Original post by Connor_leigh)
'Boron trichloride is easily hydrolysed to form two different acids as shown in the following equation.
Bcl3 + 3h20 makes(can't do an arrow) H3BO3+3HCl.
Calculate the concentration in mol dm^-3 oh hydrochloric acid produced when 43,2g of boron trichloride are added to water to form 500cm^3 of solution. Give your answer to 3 significant figures'

I've checked a mark scheme and it's saying 43.2/117.3. Can anyone tell me where the 117.3 comes from please?

What's the question

Here

Reply 1936

frozo123

12

Original post by Connor_leigh

Here

you work out number moles of boron trichloride BrCl3 so that's what the 117 thing was about.
then you look at the equation
what is the mole ratio?
then work out the conc of Hcl by rearranging moles=conxvol

Reply 1937

samb1234

13

Anyone need any help with anything? Stuck at a family friends and all my revision stuff is at home :frown:

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Reply 1938

Ultracrepidarian

2

i despise isas/empas, iv done the chemistry and physics as isas, got 31 on chemistry=(((( and 40 on physics which is okay i guess. Now i have to do an empa for chemistry which i hear are very difficult anyone have any general tips on doing it and ways to revise.