Calculate the molar mass of a diprotic acid.
The reaction reaches the endpoint of the titration with NaOH at 28ml.
The initial concentration of NaOH is 0.09792. and the initial mass of the diprotic acid is 0.685g.
How do you get to the final answer?
All of the options are around 100-150 but my answers are always much larger.
To calculate the molar mass of a diprotic acid, you need to determine the number of moles of acid used in the reaction. Once you have the moles of acid, you can divide the mass of the acid by the moles to calculate the molar mass.
Let's break down the steps:
Step 1: Calculate the moles of NaOH used in the reaction.
To do this, you need the volume of NaOH used and its concentration. In this case, you mentioned the volume used was 28 mL, and the concentration of NaOH was given as 0.09792 M (moles per liter).
Moles of NaOH = Volume (L) × Concentration (M)
Converting the volume to liters:
Moles of NaOH = 28 mL ÷ 1000 mL/L = 0.028 L
Substituting the values into the formula:
Moles of NaOH = 0.028 L × 0.09792 M = 0.00273936 moles
Step 2: Identify the stoichiometric ratio between the diprotic acid and NaOH.
The stoichiometric ratio gives the number of moles of acid reacting with one mole of NaOH. For a diprotic acid, the ratio is typically 1:2. This means one mole of diprotic acid reacts with two moles of NaOH.
Step 3: Calculate the moles of diprotic acid used in the reaction.
Since the stoichiometric ratio is 1:2, the moles of diprotic acid used will be twice the moles of NaOH used.
Moles of diprotic acid = 2 × Moles of NaOH = 2 × 0.00273936 = 0.00547872 moles
Step 4: Calculate the molar mass of the diprotic acid.
To find the molar mass, divide the mass of the diprotic acid by the moles of acid used.
Molar mass = Mass of diprotic acid (g) ÷ Moles of diprotic acid
Molar mass = 0.685 g ÷ 0.00547872 moles = 125.03 g/mol
Therefore, the molar mass of the diprotic acid is approximately 125.03 g/mol.
If your answers are significantly larger, it may indicate there was an error in your calculations or the given information. Double-check your calculations, making sure to convert units correctly, and review the given values to ensure accuracy.