For each run calculate the initial concentration of S2O3^ 2- and H+ using the di
ID: 632138 • Letter: F
Question
For each run calculate the initial concentration of S2O3^ 2- and H+ using the dilution formula. (Note: this means the concentration after dilution of the reagent in question by the other reagents, but which is the "initial" concentration at the beginning of the reaction.)
Run
Volume S2O32-(mL)
Volume H2O (mL)
Volume H+ (mL)
1
50.0
0.0
5.0
2
40.0
10.0
5.0
3
30.0
20.0
5.0
4
20.0
30.0
5.0
5
20.0
25.0
10.0
6
20.0
20.0
15.0
7
20.0
15.0
20.0
For each run calculate the initial concentration of S2O3^ 2- and H+ using the dilution formula. (Note: this means the concentration after dilution of the reagent in question by the other reagents, but which is the "initial" concentration at the beginning of the reaction.)
Run
Volume S2O32-(mL)
Volume H2O (mL)
Volume H+ (mL)
1
50.0
0.0
5.0
2
40.0
10.0
5.0
3
30.0
20.0
5.0
4
20.0
30.0
5.0
5
20.0
25.0
10.0
6
20.0
20.0
15.0
7
20.0
15.0
20.0
Explanation / Answer
Molarity = moles / Litres of solution.
Work out how many moles of each reagent you add to the initial solution.
Then use the total volume of the initial solution to determine the molarity.
eg trial 1
total volume = 50.0 ml + 0.0 ml + 5.0 ml
= 55.0 ml
= 0.0550 L
moles S2O3^2- = moles in the 50.0 ml of solution used
= molarity x Litres
= 0.0850 M x 0.0500 L
= 0.00425 moles S2O3^2-
Molarity S2O3^2- = moles added / total volume initial solution
= 0.00425 mol / 0.0550 L
= 0.0773 M S2O3^2-
moles H+ added = molarity x L
= 1.50 M x 0.0050 L
= 0.0075 moles H+
Molarity H+ = moles / Litres
= 0.0075 moles / 0.0550 L
= 0.14 M
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.