In this case, the inflection point, and
equivalence, occurs after 23.25mL of 0.40 M NaOH has been delivered.
Moles of base at the equivalence point can be determined from the volume of base delivered to
reach the equivalence point and the concentration of NaOH.
1. Calculate the moles of NaOH added to reach the equivalence point (i.e. after the addition
of 23.25 mL of 0.40 M NaOH).
2. Using the fact that the acid and base are in exact stoichiometric proportions at the
equivalence point, calculate the moles of citric acid in the solution. The balanced
equation is:
H3C6H5O7(aq) + 3 NaOH(aq) -----> Na3C6H5O7(aq) + 3H2O(l)
3. calculate the mass of citric acid in the drink mix.
1) moles = moles x L.
2) moles NaOH x (3 moles citric acid/1 mole NaOH = moles citric acid.
3). mass citric acid = moles x molar mass.
1. To calculate the moles of NaOH added to reach the equivalence point, we can use the formula:
moles = volume (in liters) * concentration
Given that the volume added is 23.25 mL (which is 0.02325 L) and the concentration is 0.40 M, we can calculate the moles of NaOH as follows:
moles of NaOH = 0.02325 L * 0.40 M = 0.0093 moles
Therefore, 0.0093 moles of NaOH were added to reach the equivalence point.
2. According to the balanced equation, the stoichiometric ratio between citric acid (H3C6H5O7) and NaOH is 1:3. Since 3 moles of NaOH react with 1 mole of citric acid, the moles of citric acid in the solution can be calculated as:
moles of citric acid = 1/3 * moles of NaOH
moles of citric acid = 1/3 * 0.0093 moles
moles of citric acid = 0.0031 moles
Therefore, there are 0.0031 moles of citric acid in the solution.
3. To calculate the mass of citric acid in the drink mix, we need to use the molar mass of citric acid. The molar mass of citric acid (H3C6H5O7) is approximately 192.14 g/mol. Therefore, the mass of citric acid can be calculated as:
mass of citric acid = moles of citric acid * molar mass of citric acid
mass of citric acid = 0.0031 moles * 192.14 g/mol
mass of citric acid = 0.5958 grams or 595.8 mg
Therefore, the mass of citric acid in the drink mix is approximately 0.5958 grams or 595.8 mg.
1. To calculate the moles of NaOH added to reach the equivalence point, you need to use the formula:
Moles = concentration (in mol/L) × volume (in L)
Given that the volume of NaOH delivered is 23.25 mL and the concentration of NaOH is 0.40 M:
Moles of NaOH = 0.40 M × (23.25 mL / 1000 mL/L)
2. Since the reaction is stoichiometrically balanced, we can determine the moles of citric acid based on the moles of NaOH present at the equivalence point. From the balanced equation, we know that the stoichiometric ratio between citric acid (H3C6H5O7) and NaOH is 1:3. Therefore, we can use this ratio to find the moles of citric acid:
Moles of citric acid = Moles of NaOH × (1 mol citric acid / 3 mol NaOH)
3. The molar mass of citric acid (H3C6H5O7) can be found in the periodic table or a chemical database. Let's assume it is 192.13 g/mol. We can use the molar mass to calculate the mass of citric acid in the drink mix:
Mass of citric acid = Moles of citric acid × molar mass of citric acid (in g/mol)
By substituting the values into the equations, you can solve for the moles of NaOH, moles of citric acid, and the mass of citric acid in the drink mix.