Soccerboi's questions thread

[jasoN-]

ion dipole, as dipoles are just partial charges, whereas ions have full charges

[Lasercookie]

Oh woops, i put the wrong question, sorry.

here's what i'm stuck on: What volume of water must be added to 10.0 mL of the stock solution to make standard 3?

10ml ---> std 3 (dilution, so amount of moles stay the same)





And since we're looking for volume of water added:

[soccerboi]

Thanks
Oh, could you explain this first part, i'm a bit confused about it. I thought concentration of standard 3 was given as 1.00X10^-3, so why do we need to divide by 368?

[Mao]

@Laseredd, you seem to be doing the dilution question in a very round-about way.







Thus 390mL should be added.

[Lasercookie]

@Laseredd, you seem to be doing the dilution question in a very round-about way.







Thus 390mL should be added.

Oh, could you explain this first part, i'm a bit confused about it. I thought concentration of standard 3 was given as 1.00X10^-3, so why do we need to divide by 368?

Ah, I converted the value to molarity and didn't pay notice to the simpler way of just using g/L like Mao pointed out.

[soccerboi]

I get it now, thanks for the help guys

[soccerboi]

When deciding on which values to use as concordant titres, what's the range it has to be within? +- 0.1ml?

[pi]

Yep, the highest and lowest titres should be within 0.10mL from each other (all other titres should be in between these two).

[soccerboi]

okay thanks, and what if there's only 2 results that lie within 0.1ml of each other, do we just use the two? or does averaging concordant titres require 3 results?

[pi]

okay thanks, and what if there's only 2 results that lie within 0.1ml of each other, do we just use the two? or does averaging concordant titres require 3 results?

Just use the two

[soccerboi]

In the production of an ester, 50.0 mL of ethanol was mixed with 50.0 mL of ethanoic
acid. The reaction was catalysed with concentrated sulphuric acid. The ester produced
was collected by distillation.

Write a balanced equation for the esterification reaction.
CH3CH2OH(l) + CH3COOH(l) → CH3COOCH2CH3(l) + H2O(l)

Why is ethanol and ethanoic acid in liquid state?

[pi]

If water is produced, I'd imagine that to make the equation useful it'd be kinda pointless reacting aqueous solutions together. Furthermore, I believe esterification needs pure reactants (I think).

Why do you think they shouldn't be liquid?

[soccerboi]

If water is produced, I'd imagine that to make the equation useful it'd be kinda pointless reacting aqueous solutions together. Furthermore, I believe esterification needs pure reactants (I think).

Why do you think they shouldn't be liquid?

I thought that because ethanol and ethanoic acid are in solution (50 ml), they should be aqueous?

[pi]

I can't see "solution" in the question stem you typed out :S Both can be liquid unless they are mixed with water (they are liquids or very close to being pure liquids naturally).

[soccerboi]

Oh i just inferred that because it's 50ml of it, that it's in aqueous solution. So it has to state the word "solution" to be aqueous?