Chemistry Unit 2 Edexcel, Exam- 23rd May 2012

recall the characteristic physical properties of the elements
limited to the appearance of solutions of the elements in water
and hydrocarbon solvents

Help!

that's just what flourine,chlorine,bromine and iodine look like normally and in water and in a hydrocarbon solvent.

Reply 381

AS01

12

Original post by UserInvalid

Just a stupid and easy question,

what is the colour of methyl orange and phanalphatalein in both acid and alkali?

and also what is the end point colour?

methly orange
acid: orange
alkali: yellow
end point: will turn from yellow to red for alkali titrated with base
phenolphthalein
alkali: pink
acid: colourless
alkali: pink
end point: go from pink to colourless for alkali titrated with acid.

Reply 382

AS01

12

Original post by YellowAndBlack

recall the characteristic physical properties of the elements
limited to the appearance of solutions of the elements in water
and hydrocarbon solvents

Help!

for physical property you need to know trend in melting point and boiling point for group 7
for group 7
colour in water
Cl- pale green
Br- brown-red/brown
I- pale brown
in hydrocarbon solvent
Cl- green
Br-brown
I-violet/mauve

Reply 383

fifty_six

will Mechanisms cum up any guesses

Reply 384

AS01

12

Original post by fifty_six

will Mechanisms cum up any guesses

the spec says you need to know mechanism for SN1 and SN2 and also for change of halogenoalkane to alkene.

Good Luck guys!

Original post by AS01

the spec says you need to know mechanism for SN1 and SN2 and also for change of halogenoalkane to alkene.

ok.. lets create a checklist,, of the topic and things we need

Reply 387

im so fresh

12

what is the hardest thing they could ask us about solubility?

Reply 388

AS01

12

Original post by fifty_six

ok.. lets create a checklist,, of the topic and things we need

ok

Reply 389

AS01

12

Original post by im so fresh

what is the hardest thing they could ask us about solubility?

don't think anything hard will come up if worse comes worst then why they decompose at low temperature.

Reply 390

jerichi

Hey guys! I'm sure some people already know and use this site but others might not so check it out!

http://www.knockhardy.org.uk/sci.htm

It's a great site for notes!!!
xo

Reply 391

phaseshift

12

Original post by fifty_six

ok.. lets create a checklist,, of the topic and things we need

I'm putting one together now reading through the spec, half hour and it should be done. :smile:

Reply 392

egg123

Why does something with one lone pair and two bond pairs (sulphur dioxide) have v-shaped arrangement, when also h20 has same v-shaped with same angle, but it has two lone paris and two bond pairs????

Reply 393

AS01

12

Original post by HarryMWilliams

I'm putting one together now reading through the spec, half hour and it should be done. :smile:

hey!!
do you wanna ask question?

Reply 394

phaseshift

12

Original post by AS01

hey!!
do you wanna ask question?

Will do after i've finished this checklist! :smile:

(edited 11 years ago)

Reply 395

oli_G

12

I think the actual angle is 120 degrees as there are three electron pairs. You would expect the bond angle to be shortened due to the lone pair but the fact that the S=O bond is stereochemically different means the extra repulsion is cancelled out, giving a trigonal planar molecule.

Reply 396

egg123

Why does something with one lone pair and two bond pairs (sulphur dioxide) have v-shaped arrangement, when also h20 has same v-shaped with same angle, but it has two lone paris and two bond pairs????

Reply 397

oli_G

12

Original post by egg123

Why does something with one lone pair and two bond pairs (sulphur dioxide) have v-shaped arrangement, when also h20 has same v-shaped with same angle, but it has two lone paris and two bond pairs????