chemistry unit 3 !!! discussion in here !! =p

[code11]

the gas is hydrogen, sodium disappears, white ppt of sodium propoxide formed

i doubt the white ppt part .cuz the only salt formed is organic salt ! correct me if m wrong

 

[U stalking ME]

i doubt the white ppt part .cuz the only salt formed is organic salt ! correct me if m wrong

yes it is organic but it is a white solid product which is ionic so a white ppt is formed

 

[code11]

does so2 smell like bad egg ?

 

[U stalking ME]

does so2 smell like bad egg ?

hydrogen sulfide smells of rotten eggs and SO2 turns acidified potassium dichromate(VI) paper from yellow to green.

 

[DANGERBP]

CH3CH2CH2OH(l) + Na(s) = CH3CH2CH2O-Na+(s) + 0.5H2(g)

and the white solid ? =/
man sorry but ma mind don work much in these stuff =/

 

[U stalking ME]

and the white solid ? =/
man sorry but ma mind don work much in these stuff =/

CH3CH2CH2O-Na+(s) <---------- this is the white solid

 

[DANGERBP]

CH3CH2CH2O-Na+(s) <---------- this is the white solid

ugh ya r8 ! nd the name of it is ? =$

 

[U stalking ME]

ugh ya r8 ! nd the name of it is ? =$

In this case, sodium propoxide (depends on the alcohol used)

 

[DANGERBP]

guyz do any of u got a link to all rxns we need to know ! or some .. =/ i feel like i forgot everythin !

 

[DANGERBP]

In this case, sodium propoxide (depends on the alcohol used)

thank you lots !

 

[U stalking ME]

guyz do any of u got a link to all rxns we need to know ! or some .. =/ i feel like i forgot everythin !

yea i also need it!! Anyone plzz help

 

[U stalking ME]

thank you lots !

dude welcome

 

[DANGERBP]

dude welcome

heh =p !

 

[DANGERBP]

hey how do we know which rxns r exo or endo when we calculatin the enthalpy change ??

 

[U stalking ME]

hey how do we know which rxns r exo or endo when we calculatin the enthalpy change ??

if they say temp rises or a -value is given its exothermic
if they say say temp dropped or a +value then its endothermic

 

[DANGERBP]

if they say temp rises or a -value is given its exothermic
if they say say temp dropped or a +value then its endothermic

mm.. another question heat enthalpy per mol we should wr8 -ve or +ve thats it r8 ??
but when we calculate the total enthalpy no ?
or the opposite ? =$ =p !
thx again =p !

 

[DANGERBP]

wats decanting ?
nd wats precipitation ?

 

[¦HaLo¦]

http://www.thestudentroom.co.uk/wik...boratory_Techniques_-_Group_1_and_2_Reactions

 

[xIshtar]

Heat enthalpy depends on the reaction, as someone said, temperature rise, then the energy value will be positive.
Temperature fall and it will be negative.
Decanting is when you pour off some of the liquid on the top, to try and leave only the solid behind.

 

[U stalking ME]

wats decanting ?
nd wats precipitation ?

Decanting can be used to separate a liquid from an insoluble solid. As the solid settles to the bottom of the container, the liquid can be carefully poured into another container leaving the solid (sediment) behind. Decanting can also be used to separate two immiscible liquids like oil and vinegar.

Precipitation reactions: When an insoluble solid called a precipitate forms when reactants are formed together.
For example, when carbon Dioxide is mixed with Calcium Hydroxide (Limewater), The precipitate Calcium carbonate is formed.