[pinkturtle]

im sure its really simple but i just cant seem to get sensible answer/ am not sure if my answers are sensible so any coments will be greatfully recieved !!
TITRATION
this is what ive got in my report so far but ive got myself in a bit of a pickle!!!

 25cm3 of sodium carbonate put into a conical flask. A 0.2 M solution of hydrochloric acid solution was added . Methyl orange was the indicator turned a grey colour when 26.37ml of the hydrochloric acid solution had been added

So I know the ratio (no of moles) of sodium carbonate and its volume
I can calculate the number of moles of sodium carbonate in my standard solution
 then I know the number of moles of sodium carbonate and the volume of the solution I made up (250mL) so I can work out the concentration of the 25ml of sodium carbonate in the conical flask.


Sodium carbonate (aq) + Hydrochloric acid (aq) ? Sodium chloride (aq) + Water (l) + Carbon dioxide (g)
Na2CO3 (s) + 2 HCl (aq) ? 2 NaCl (aq) + CO2 (g) + H2O (l)
1 mole of sodium carbonate reacts with 2 moles of hydrochloric acid

(250cm3 is 0.25 dm3).  
C = N/V I will calculate the moles of sodium carbonate =1/0.250 = 4 mol dm-3.  
The number of moles in 25ml of my standard solution is
N = C x V
0.4 mol dm-3 x 25ml= 10

Where:
N = number of moles,
C = concentration in mol dm-3
And V = volume of solution in dm3
im in a right mess people !!!!deperatly need a pointer in the right direction as so as u throw numbers in to the situation im completely lost !!

[xiankai]

C = N/V I will calculate the moles of sodium carbonate =1/0.250 = 4 mol dm-3.

is there really 1 mole of Na2CO3 in 25 cm3 of that solution?

while 1 mole of Na2CO3 reacts with 2 moles of HCl, this is just a ratio, and not definite numbers.

first, convert all given data to moles, then fit them into the ratio.

[Albert]

I cannot SEE your question. Do you need to calculate the molarity of sodium carbonate in your 25 mL flask?

[pinkturtle]

well i have to do a few calculations
- concentration of sodium carbonate in standard solution
- concentration of HCL

[Albert]

well i have to do a few calculations
- concentration of sodium carbonate in standard solution
- concentration of HCL

If you've also to determine the concentration of HCl, you must know (and post   ) the weight of sodium carbonate.

[pinkturtle]

erm i think i already did
i used 2.62g of sodium and diluted it with distilled water

[Albert]

Ok, you didn't. By the way, with the MW of sodium carbonate, determine the moles of primary standard. Then, using the ratio 250mL/25mL, you can easily determine the moles of sodium carbonate in the 25 mL you used for the titration and the exact concentration of HCl.