A student titrated 1.852 g of a mixture containing potassium hydrogen phthalate, KHP....?
A student titrated 1.852 g of a mixture containing potassium hydrogen phthalate, KHP,
with 0.163 M NaOH solution. She recorded an initial buret reading of 0.84 mL and a final
buret reading of 31.32 mL.
“KHP” is shorthand for a certain acid. It contains NO phosphorus.
•Write the reaction equation for the acid-base neutralization.
I got NaOH+KHC8H4O4-->H2O+KNaC8H4O4 is this correct?
•Name the secondary standard used in the titration of the unknown KHP mixture.
• Calculate the amount of NaOH (in millimoles) delivered in the titration.
• Find the mass of KHP neutralized in the reaction.
• Calculate the mass percent of KHP in the original sample.
got NaOH+KHC8H4O4-->H2O+KNaC8H4O4 is this correct?
yes
•Name the secondary standard used in the titration of the unknown KHP mixture.
NaOH
• Calculate the amount of NaOH (in millimoles) delivered in the titration.
mL x M = millimols
• Find the mass of KHP neutralized in the reaction.
millimoles KHP = millimoles NaOH
g KHP = (millimoles/1000)*molar mass
• Calculate the mass percent of KHP in the original sample.
%KHP in sample = (grams KHP/mass sample)*100 = ?
Why did the acid go to therapy? It had unresolved pH issues!
• The reaction equation for the acid-base neutralization is correct: NaOH + KHC8H4O4 → H2O + KNaC8H4O4.
• The secondary standard used in the titration of the unknown KHP mixture is NaOH.
• To calculate the amount of NaOH delivered in the titration, we need to find the difference between the initial and final buret readings:
Volume of NaOH delivered = Final buret reading - Initial buret reading
= 31.32 mL - 0.84 mL
= 30.48 mL.
Then, we can calculate the amount of NaOH in millimoles:
Amount of NaOH (in millimoles) = Volume of NaOH delivered (in mL) * Concentration of NaOH (in M)
= 30.48 mL * 0.163 M
≈ 4.97 mmol.
• The mass of KHP neutralized in the reaction can be calculated based on the amount of NaOH used. The stoichiometric ratio between NaOH and KHP is 1:1. Since 1 mole of KHP has a molar mass of 204.23 g, the mass of KHP neutralized is:
Mass of KHP neutralized = Amount of NaOH used (in mmol) * Molar mass of KHP (in g/mol)
= 4.97 mmol * 204.23 g/mol
≈ 1015.63 mg.
• Finally, to calculate the mass percent of KHP in the original sample, we use the equation:
Mass percent of KHP = (Mass of KHP neutralized / Mass of the original sample) * 100%
However, we need to know the mass of the original sample to proceed with this calculation.
• The reaction equation for the acid-base neutralization between NaOH and KHP is:
KHC8H4O4 (KHP) + NaOH → H2O + KNaC8H4O4
Your equation is correct!
• The secondary standard used in the titration of the unknown KHP mixture is NaOH.
• To calculate the amount of NaOH (in millimoles) delivered in the titration, we need to use the equation:
moles NaOH = (volume of NaOH in liters) x (molarity of NaOH)
First, convert the initial and final buret readings to liters:
Initial buret reading = 0.84 mL = 0.00084 L
Final buret reading = 31.32 mL = 0.03132 L
Volume of NaOH used = Final buret reading - Initial buret reading = 0.03132 L - 0.00084 L = 0.03048 L
Now, substitute the values into the equation:
moles NaOH = (0.03048 L) x (0.163 mol/L)
moles NaOH = 0.00497224 mol
Finally, convert moles to millimoles by multiplying by 1000:
millimoles NaOH = 0.00497224 mol x 1000 = 4.97224 mmol
Therefore, the amount of NaOH delivered in the titration is approximately 4.97224 millimoles.
• To find the mass of KHP neutralized in the reaction, we need to use the stoichiometry of the balanced equation. The molar ratio between KHC8H4O4 and NaOH is 1:1.
Mass of KHP neutralized = moles of NaOH used x molar mass of KHP
The molar mass of KHP (KHC8H4O4) is approximately 204.23 g/mol.
Substitute the values into the equation:
Mass of KHP neutralized = 0.00497224 mol x 204.23 g/mol
Mass of KHP neutralized = 1.016 g
Therefore, the mass of KHP neutralized in the reaction is approximately 1.016 g.
• To calculate the mass percent of KHP in the original sample, we need to use the formula:
Mass percent = (mass of KHP / mass of original sample) x 100
Substitute the values into the equation:
Mass percent KHP = (1.016 g / 1.852 g) x 100
Mass percent KHP = 54.92%
Therefore, the mass percent of KHP in the original sample is approximately 54.92%.
• Reaction equation for the acid-base neutralization:
The correct balanced chemical equation for the acid-base neutralization between NaOH and KHP is:
KHC8H4O4 + NaOH -> H2O + KNaC8H4O4
• Secondary standard used in the titration:
The secondary standard used in the titration is NaOH (Sodium Hydroxide) solution.
• Calculation of the amount of NaOH (in millimoles) delivered in the titration:
To calculate the amount of NaOH delivered in the titration, we need to use the equation for molarity (M) and volume (V):
M1 * V1 = M2 * V2
Where:
M1 = Molarity of NaOH solution (0.163 M)
V1 = Volume of NaOH solution used in the titration (final buret reading - initial buret reading in liters)
Given:
Initial buret reading = 0.84 mL = 0.84 * 10^-3 L
Final buret reading = 31.32 mL = 31.32 * 10^-3 L
V1 = 31.32 * 10^-3 L - 0.84 * 10^-3 L = 30.48 * 10^-3 L
Now we can substitute the values into the equation:
(0.163 M) * (30.48 * 10^-3 L) = M2 * V2
Solving for M2:
M2 = (0.163 M) * (30.48 * 10^-3 L) / V2
• Calculation of the mass of KHP neutralized in the reaction:
To calculate the mass of KHP neutralized in the reaction, we need to convert the moles of NaOH to moles of KHP using stoichiometry from the balanced equation.
From the balanced equation, we know that the molar ratio between NaOH and KHP is 1:1.
We calculated the moles of NaOH in the previous step, which is M2 * V2.
Therefore, the moles of KHP neutralized is also M2 * V2.
Now we can calculate the mass of KHP neutralized using its molar mass (204.22 g/mol):
Mass of KHP neutralized = (M2 * V2) * (molar mass of KHP)
• Calculation of the mass percent of KHP in the original sample:
To calculate the mass percent of KHP in the original sample, we need to use the following formula:
Mass percent = (mass of KHP / mass of the original sample) * 100
For the mass of the original sample, it is mentioned that 1.852 g of a mixture containing KHP was titrated.
Therefore, the mass percent of KHP in the original sample is:
Mass percent = (mass of KHP neutralized / 1.852 g) * 100