• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Ask me for chemistry help! (4 Viewers)

D

Dylanamali

Active Member
Joined
Jul 7, 2009
Messages
1,248
Gender
Male
HSC
2011
kittyful said:
So does that mean that the end conc. will be higher than expected ?

:D
Click to expand...
Kitty also note.. that a somewhat difficult question they ask, is why the conical flask containing the unknown solution is rinsed with distilled water and not the solution it is going to contain. This is because the only thing that matters is the no. of mols of unknown that is in the flask - that is, the concentration becomes irrelevant as a titration is just determining the equilavence pt - which is the pt where there are equal number of mols of OH- and H+. So as long as you have the known number of mols it is okay.
 
kittyful

kittyful

Member
Joined
Oct 2, 2009
Messages
153
Gender
Female
HSC
2011
MagnificentOne said:
I've got a question for you guys.
Is Sodium carbonate acidic, basic or neutral? Explain. Use equations.
Click to expand...
Sodium carbonate is basic. Because it contains a conjugate acid of a strong base and CO3 is a conjugage base of a weak acid .

and err i don't have an equation for this
 
kittyful

kittyful

Member
Joined
Oct 2, 2009
Messages
153
Gender
Female
HSC
2011
Dylanamali said:
Kitty also note.. that a somewhat difficult question they ask, is why the conical flask containing the unknown solution is rinsed with distilled water and not the solution it is going to contain. This is because the only thing that matters is the no. of mols of unknown that is in the flask - that is, the concentration becomes irrelevant as a titration is just determining the equilavence pt - which is the pt where there are equal number of mols of OH- and H+. So as long as you have the known number of mols it is okay.
Click to expand...
Thanks :D
 
M

mangoz

Member
Joined
Jul 17, 2011
Messages
136
Location
chicken
Gender
Male
HSC
2011
kittyful said:
Sodium carbonate is basic. Because it contains a conjugate acid of a strong base and CO3 is a conjugage base of a weak acid .

and err i don't have an equation for this
Click to expand...
Just react it with water lol
 
D

Dylanamali

Active Member
Joined
Jul 7, 2009
Messages
1,248
Gender
Male
HSC
2011
mangoz said:
Just react it with water lol
Click to expand...
hmm, if you react it with a water, it should act as a bronsted lowry base, accepting a proton. That is:

Na2CO3 + H2O -> Na2HCO3+ + OH-

Is that product - sodium hydrogen carbonate, if so, isn't that substance amphiprotic? Just a side note, isn't it strange that a basic substance ionises to form a amphiprotic substance. =/
 
D

Dylanamali

Active Member
Joined
Jul 7, 2009
Messages
1,248
Gender
Male
HSC
2011
kittyful said:
How would you draw dilute HCL ?
Click to expand...
dilute HCl:

HCl is a strong acid, meaning that it is completely ionised, that means you have to draw only H+ and Cl- ions (NO HCl molecular ions!!)

If it is dilute, that just means you don't draw many of the ions e.g. in a strong you'd draw many H+ and Cl- ions, in dilute you draw few..
 
kittyful

kittyful

Member
Joined
Oct 2, 2009
Messages
153
Gender
Female
HSC
2011
Dylanamali said:
dilute HCl:

HCl is a strong acid, meaning that it is completely ionised, that means you have to draw only H+ and Cl- ions (NO HCl molecular ions!!)

If it is dilute, that just means you don't draw many of the ions e.g. in a strong you'd draw many H+ and Cl- ions, in dilute you draw few..
Click to expand...
oh right thanks :D
 
You must log in or register to reply here.

Users Who Are Viewing This Thread (Users: 0, Guests: 4)

Top