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1. Attachment 695062Is the answer to b 7.87 gdm-3
2. (Original post by HN786)
Attachment 695062Is the answer to b 7.87 gdm-3
I'm sorry, I couldnt find the attachment...
3. (Original post by Iluv2edgedsword)
I'm sorry, I couldnt find the attachment...
This work?
4. (Original post by HN786)
This work?
I got 3.94 gdm^-3 (half of what you got):

0.0528 moldm^-3 * 0.025 dm^3 = 0.001321 mol of sodium carbonate
Each mole of sodium carbonate requires 2 moles of hydrochloric acid, so 0.001321*2 = 0.2642 moles of hydrocholoric acid were used.
0.2642 mol / 0.0245 dm^3 = 0.1078 moldm^-3 hydrochloric acid
RFM of hydrochloric acid is 1 + 35.5 = 36.5 (your periodic table may have slightly different values - use those).
0.1078 moldm^-3 * 36.5 gmol^-1 = 3.94 gdm^-3.
5. (Original post by TheMindGarage)
I got 3.94 gdm^-3 (half of what you got):

0.0528 moldm^-3 * 0.025 dm^3 = 0.001321 mol of sodium carbonate
Each mole of sodium carbonate requires 2 moles of hydrochloric acid, so 0.001321*2 = 0.2642 moles of hydrocholoric acid were used.
0.2642 mol / 0.0245 dm^3 = 0.1078 moldm^-3 hydrochloric acid
RFM of hydrochloric acid is 1 + 35.5 = 36.5 (your periodic table may have slightly different values - use those).
0.1078 moldm^-3 * 36.5 gmol^-1 = 3.94 gdm^-3.
Why would you multiply the moles of sodium carbonate by 0.025
6. Hi, just to jump in. They multiplied the concentration (0.0528M) by the volume (0.025dm3 or 25cm3) in order to get the moles, as moles = conc * vol
7. 1.4g = 1.4/106 = 0.013 moles

0.013 moles in 250ml

therefore there is 4x0.013 moles of of sodium carbonate in 1dm^3 = 0.052 mol/dm^3

25ml of 0.052 molar solution of sodium carbonate reacts with 24.5 ml HCl.

The molarity of the acid is 25x2x0.052/24.5 = 0.106mol/dm^3

There is 0.106x36.5g = 3.87g/dm^3

My answer has fewer rounding errors.
8. (Original post by TheMindGarage)
I got 3.94 gdm^-3 (half of what you got):

0.0528 moldm^-3 * 0.025 dm^3 = 0.001321 mol of sodium carbonate
Each mole of sodium carbonate requires 2 moles of hydrochloric acid, so 0.001321*2 = 0.2642 moles of hydrocholoric acid were used.
0.2642 mol / 0.0245 dm^3 = 0.1078 moldm^-3 hydrochloric acid
RFM of hydrochloric acid is 1 + 35.5 = 36.5 (your periodic table may have slightly different values - use those).
0.1078 moldm^-3 * 36.5 gmol^-1 = 3.94 gdm^-3.
Because you used 25cm^3 of it. 25cm^3 = 0.025dm^3.
9. (Original post by TheMindGarage)
Because you used 25cm^3 of it. 25cm^3 = 0.025dm^3.
Just wanted to check if i got these questions right, my answer for a was 0.0432moldm3
My answer to b was 9.72gm3

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