x Turn on thread page Beta
 You are Here: Home

# AS Chemistry- helping each other out! watch

1. (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

Posted from TSR Mobile
2. (Original post by samb1234)
Its the Mr of BCl3

Posted from TSR Mobile
Thanks! I used the proton number of boron.... My Mr calculation of BCl3 came out wrong. Thats why i was so confused
3. Can someone also please explain why you times to moles of Hcl by 1000/500? Thanks in advance
4. (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

Posted from TSR Mobile
5. (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
6. (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
7. Anyone need any help with anything? Stuck at a family friends and all my revision stuff is at home

Posted from TSR Mobile
8. 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.
9. Does anybody know what 32 marks in the AS edexcel chemistry controlled assessment is? Is it a C?
10. (Original post by TheonlyMrsHolmes)
Does anybody know what 32 marks in the AS edexcel chemistry controlled assessment is? Is it a C?
I think that would be yes. I know that a is 37 so I reckon b is probably 34ish

Posted from TSR Mobile
11. (Original post by samb1234)
I think that would be yes. I know that a is 37 so I reckon b is probably 34ish

Posted from TSR Mobile
Oh well, whats done is done, I found the experience painful, I just cannot to practicals. Thankyou for replying!
12. (Original post by TheonlyMrsHolmes)
Oh well, whats done is done, I found the experience painful, I just cannot to practicals. Thankyou for replying!
Any of the practicals in particular that didnt go so well?

Posted from TSR Mobile
13. (Original post by samb1234)
Any of the practicals in particular that didnt go so well?

Posted from TSR Mobile
My titration one but I suspected that since I was holding my thumb under the glass pipette to stop the HCL dripping out and my non-organic. I lost 4 marks in both
16. Hey all

If you need any extra revision materials - questions (+ answers!) and notes - check out my website www.scienceskool.co.uk All totally free, no ads and can all be viewed offline once downloaded of course. I hope you find it useful.

Alex
17. The first five successive ionization energies of an element, X, are shown in the tablebelow.

Ionization energy: first second third fourth fifth
Value/ kJ mol–1 590 1100 4900 6500 8100

Which ion is X most likely to form when it reacts with chlorine?
A X+
B X2+
C X3+
D X4+

18. (Original post by alevels2k15)
The first five successive ionization energies of an element, X, are shown in the tablebelow.

Ionization energy: first second third fourth fifth
Value/ kJ mol–1 590 1100 4900 6500 8100

Which ion is X most likely to form when it reacts with chlorine?
A X+
B X2+
C X3+
D X4+

I'm assuming it's B because there's a huge jump between the second and third ionisation energy.
19. (Original post by frozo123)
I'm assuming it's B because there's a huge jump between the second and third ionisation energy.
BUT how?
20. (Original post by alevels2k15)
BUT how?
well what do you know about ionisation energies atm?

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: July 24, 2017
Today on TSR

### Loughborough better than Cambridge

Loughborough at number one

### Can I date a girl with no boobs?

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE