I used 10mL of unknown NaCl-NaBr mixture titrate with 0.10M silver nitrate solution.
10.15mL of silver nitrate solution is used.
the conc. of NaCl-NaBr mixture is 8g/dm3
I need to calculate the % composition of the NaCl-NaBr mixture.
Let X = grams NaCl
Let Y = grams NaBr
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X + Y = 0.08 g. (That's 8 x (10/1000) = ?
moles X + moles Y = M x L or
(X/molar mass NaCl) + (Y/molar mass NaBr) = 0.1 x 0.01015.
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Solve the two equations simultaneously, then
%NaCl = (g NaCl/mass sample)*100 = ??
%NaBr = (g NaBr/mass sample)*100 = ??
To calculate the percent composition of the NaCl-NaBr mixture, you need to determine the amounts of NaCl and NaBr in the mixture and express them as a percentage of the total mass.
1. Calculate the number of moles of AgNO3 reacted:
Moles of AgNO3 = concentration of AgNO3 solution (0.10 M) * volume of AgNO3 solution used (10.15 mL or 0.01015 L)
2. Convert the moles of AgNO3 reacted to moles of Cl- ions:
Since AgNO3 reacts with Cl- ions in a 1:1 molar ratio, the moles of Cl- ions present in the mixture are equal to the moles of AgNO3 reacted.
3. Calculate the mass of Cl- ions:
Mass of Cl- ions = moles of Cl- ions * molar mass of Cl- (35.45 g/mol)
4. Calculate the mass of NaCl in the mixture:
Mass of NaCl = mass of Cl- ions / (molar mass of Cl- * 1)
5. Calculate the mass of NaBr in the mixture:
Mass of NaBr = Total mass of NaCl-NaBr mixture - Mass of NaCl
6. Calculate the total percentage composition:
Percentage of NaCl = (Mass of NaCl / Total mass of NaCl-NaBr mixture) * 100%
Percentage of NaBr = (Mass of NaBr / Total mass of NaCl-NaBr mixture) * 100%
Note: You mentioned the concentration of the mixture as 8 g/dm3. However, since this is a titration, we can't directly use the concentration to determine the mass of the mixture. We'll calculate the percentage composition based on the mass of the components.
Let's perform the calculations:
To calculate the % composition of the NaCl-NaBr mixture, you need to determine the moles of silver nitrate used in the titration.
First, calculate the moles of silver nitrate used:
Moles of AgNO3 = concentration of AgNO3 * volume of AgNO3 used
Given:
Concentration of AgNO3 = 0.10 M
Volume of AgNO3 used = 10.15 mL = 0.01015 L
Moles of AgNO3 = 0.10 M * 0.01015 L = 0.001015 moles
Next, you need to determine the moles of chloride ions (Cl-) present in the NaCl-NaBr mixture based on the reaction between AgNO3 and NaCl:
AgNO3 (aq) + NaCl (aq) -> AgCl (s) + NaNO3 (aq)
From the balanced equation, you can see that 1 mole of AgNO3 reacts with 1 mole of NaCl to form 1 mole of AgCl. Therefore, the moles of AgNO3 used in the titration are equal to the moles of chloride ions present.
Moles of Cl- = 0.001015 moles
Since the NaCl-NaBr mixture contains only Cl- and Br- ions, the total moles of Cl- and Br- would be equal to Moles of Cl- + Moles of Br-.
Now, we can calculate the moles of NaCl-NaBr mixture:
Moles of NaCl-NaBr = Moles of Cl- + Moles of Br-
To calculate the % composition of NaCl-NaBr, use the formula:
% composition = (moles of component / total moles) * 100
For NaCl:
% composition of NaCl = (Moles of NaCl / Moles of NaCl-NaBr) * 100
Since NaBr is the only other component in the mixture, the % composition of NaBr can be calculated as:
% composition of NaBr = (Moles of Br- / Moles of NaCl-NaBr) * 100
Note: In order to calculate the moles of NaCl-NaBr mixture, you will also need to know the molecular weights of NaCl and NaBr.