C₆H₈O₇ = 192 g/mol
Molar mass is the sum of the atomic weight of the atoms present in compound.
Formula of citric acid:
Atomic weight of hydrogen = 1 amu
Atomic weight of carbon = 12 amu
Atomic weight of oxygen = 16 amu
C₆ = 6 × 12 = 72 g/mol
H₈ = 8 × 1 = 8 g/mol
O₇ = 7 × 16 = 112 g/mol
C₆H₈O₇ = 72 g/mol + 8 g/mol + 112 g/mol
C₆H₈O₇ = 192 g/mol
1. 192.0 g/mol.
2. 84.0 g/mol.
Explanation:The molar mass is the mass of all the atoms in a molecule in grams per mole.To calculate the molar mass of a molecule, we first obtain the atomic weights from the individual elements in a periodic table. We then count the number of atoms and multiply it by the individual atomic masses.
1. Molar mass of citric acid (C₆H₈O₇):
Molar mass of C₆H₈O₇ = 6(atomic mass of C) + 8(atomic mass of H) + 7(atomic mass of O) = 6(12.0 g/mol) + 8(1.0 g/mol) + 7(16.0 g/mol) = 192.0 g/mol.
2. Molar mass of baking soda (NaHCO₃):
Molar mass of NaHCO₃ = (atomic mass of Na) + (atomic mass of H) + (atomic mass of C) + 3(atomic mass of O) = (23.0 g/mol) + (1.0 g/mol) + (12.0 g/mol) + 3(16.0 g/mol) = 84.0 g/mol.
To solve this problem we first need to calculate the amount of citric acid contained in a 3.71 g sample of lemon juice.The only data of concentration we're given is a mass procent, that 0.5% of the mass of a sample is citric acid:3.71 g * 0.5/100 = 0.01855 g citric acid
Now with the molar mass of citric acid we can calculate the moles:0.01855 g citric acid ÷ 190.12 g/mol = 9.757x10⁻⁵ mol citric acid
Because citric acid is a monoprotic acid, one mol of acid will react with one mol of NaOH, thus we calculate the volume of 0.0100 M NaOH that has 9.757x10⁻⁵ mol:
Concentration = mol/Volume
0.0100 M = 9.757x10⁻⁵ mol / Volume
Volume = 9.76x10⁻³L = 9.76 mL
The volume to neutralize the sample of lemon juice is 9,76mL
3,71 g sample of lemon juice are:
3,71 g × = 0,01855 g of citric acid. In moles:
0,01855 g × = 9,76x10⁻⁵ moles of citric acid.
Assuming this acid is a monoprotic acid, the moles of NaOH required to neutralized the citric acid are 9,76x10⁻⁵ moles
As the molar concentration of NaOH is 0,0100 mol/L. The volume to neutralize the sample of lemon juice is:
9,76x10⁻⁵ moles × = 9,76x10⁻³L ≡ 9,76 mL
I hope it helps!