Chemistry volumetric analysis.
B is a solution of Na2CO3 containing 5g/dm3.
A is a solution of oxalic acid of uknown concentration 25cm3 of 25.25,25.0 and 24.80 respectively
(I) Calculate the average volume of acid used
(II) The molar concentration of solution A
(III) The molar concentration of solution B
Was this an experiment? What was done?
To solve this question, we will use the concept of volumetric analysis, where we will titrate the oxalic acid solution (A) with the sodium carbonate solution (B).
(I) Calculating the Average Volume of Acid Used:
1. Observe that we have three different volume readings for solution A: 25.25 cm3, 25.0 cm3, and 24.80 cm3.
2. Calculate the average volume by summing up the three readings and dividing by the number of readings.
Average volume = (25.25 + 25.0 + 24.80) cm3 / 3 = 24.85 cm3
(II) Calculating the Molar Concentration of Solution A:
1. We know that the volume of solution A used is 24.85 cm3.
2. The balanced equation for the reaction is:
2H2C2O4 (oxalic acid) + Na2CO3 → H2C2O4-Na2 + CO2 + H2O
3. According to the equation, one mole of oxalic acid reacts with one mole of sodium carbonate.
4. The molar concentration of solution A can be calculated using the formula:
Molarity = (mol of solute) / (volume of solution in liters)
5. Since the equation is 1:1, the number of moles of oxalic acid used will be the same as the number of moles of sodium carbonate in solution B.
Moles of Na2CO3 = (Mass of Na2CO3) / (Molar Mass of Na2CO3)
= (5g/dm3) / (Molar Mass of Na2CO3)
6. Convert cm3 to dm3 by dividing by 1000 (1 cm3 = 1/1000 dm3).
Volume of Solution A = 24.85 cm3 / 1000 dm3/cm3 = 0.02485 dm3
7. Calculate the molar concentration of solution A:
Molarity of A = Moles of Na2CO3 / Volume of A in liters
= Moles of Na2CO3 / 0.02485 dm3
(III) Calculating the Molar Concentration of Solution B:
1. We know that the mass of sodium carbonate (Na2CO3) in solution B is 5g/dm3.
2. The molar mass of Na2CO3 is the sum of the atomic masses of sodium (Na), carbon (C), and oxygen (O).
Molar Mass of Na2CO3 = (2 * Atomic Mass of Na) + Atomic Mass of C + (3 * Atomic Mass of O)
= (2 * 23) + 12 + (3 * 16)
= 106 g/mol
3. The molar concentration of solution B can be calculated using the formula:
Molarity = (mass of solute) / (molar mass of solute) * (volume of solution in liters)
Molarity of B = (5g/dm3) / (106 g/mol) * (0.02485 dm3)
Note: Make sure to convert units to the same system (e.g., dm3) before performing the calculations.