Citric acid H3C6H5O7, occurs in plants. Lemons contain 5% to 8% citric acid by mass. The acid is added to beverages and candy. An aqueous solution is 0.688m citric acid. The density is 1.049 g/ml. What is the molar concentration?
answered below.
To determine the molar concentration of the aqueous solution of citric acid, you need to convert the mass percent composition to molar concentration. Here's how you can do it:
1. Start by calculating the mass of citric acid in the solution:
Mass of solution = Density × Volume of solution
Since the density is given as 1.049 g/ml, and no volume is provided, you cannot calculate the exact mass of the solution. Therefore, let's assume that you have 100 ml of the solution for the sake of finding the molar concentration.
Mass of solution = 1.049 g/ml × 100 ml
Mass of solution = 104.9 g
2. Calculate the mass of citric acid in the solution using the percentage composition:
Mass of citric acid = Mass of solution × Mass percent composition
Mass of citric acid = 104.9 g × 0.688
Mass of citric acid = 72.14 g
3. Next, calculate the molar mass of citric acid:
The molar mass of citric acid (H3C6H5O7) is calculated as:
Molar mass = (3 × molar mass of H) + (6 × molar mass of C) + (5 × molar mass of H) + (7 × molar mass of O)
Molar mass = (3 × 1.007 g/mol) + (6 × 12.011 g/mol) + (5 × 1.007 g/mol) + (7 × 15.999 g/mol)
Molar mass = 192.123 g/mol
4. Finally, calculate the molar concentration (M) of the citric acid solution:
Molar concentration = Mass of citric acid / Molar mass of citric acid
Molar concentration = 72.14 g / 192.123 g/mol
Molar concentration ≈ 0.375 M
Therefore, the molar concentration of the aqueous solution of citric acid is approximately 0.375 M (molar).