Given the following equation and information answer the following questions,
KHC8H4O4 (aq) + NaOH(aq) > KNaC8H4O4 (aq) + H2O(l)
3. What is the molarity of a NaOH solution if 26.50 mL of it is required to neutralize 0.4150 g of pure KHP? (3 points)
4. What is the percentage of KHP in an impure sample of KHP that weighs 0.4200 g and requires 14.00 mL of 0.098 M NaOH to neutralize it? (4 points)
mols KHP = grams/molar mass = ?
mols NaOH in a 1:1 reaction = mols KHP.
Then M NaOH = mols NaOH/ L NaOH = ?
#4. mols NaOH = M x L = ?
mols KHP = mols NaOH
grams KHP = mols KHP x molar mass KHP.
%KHP = (grams KHP/mass sample)*100 = ?
To solve these questions, we'll use the concept of stoichiometry.
3. To find the molarity of the NaOH solution, we can use the equation:
Molarity (M) = moles of solute / volume of solution (in liters)
First, we need to calculate the number of moles of KHP (potassium hydrogen phthalate) in the given mass. The molar mass of KHP is 204.23 g/mol. Let's calculate the moles:
moles of KHP = mass of KHP / molar mass of KHP
= 0.4150 g / 204.23 g/mol
= 0.002032 mol
Now, we need to determine the volume of the NaOH solution that is required to neutralize the KHP. The given volume is 26.50 mL, which is equivalent to 0.02650 L.
Next, we use the equation to calculate the molarity:
Molarity of NaOH = moles of NaOH / volume of NaOH solution
Since the reaction is a 1:1 ratio between KHP and NaOH, the moles of NaOH used will be the same as the moles of KHP. So:
Molarity of NaOH = 0.002032 mol / 0.02650 L
= 0.0766 M
Therefore, the molarity of the NaOH solution is 0.0766 M.
4. To find the percentage of KHP in the impure sample, we can use the equation:
Percentage of KHP = (mass of KHP in the impure sample / mass of impure sample) * 100
First, we need to calculate the moles of NaOH used in the reaction. The molarity of NaOH is given as 0.098 M, and the volume used is 14.00 mL, which is 0.01400 L. Let's calculate the moles of NaOH:
moles of NaOH = molarity * volume
= 0.098 M * 0.01400 L
= 0.001372 mol
Since the reaction is a 1:1 ratio between KHP and NaOH, the moles of NaOH used will be the same as the moles of KHP. So:
moles of KHP in the impure sample = 0.001372 mol
Next, we can calculate the mass of KHP in the impure sample:
mass of KHP in the impure sample = moles of KHP * molar mass of KHP
= 0.001372 mol * 204.23 g/mol
= 0.2806 g
Now, we can find the percentage of KHP in the impure sample:
Percentage of KHP = (0.2806 g / 0.4200 g) * 100
= 66.8%
Therefore, the impure sample of KHP is approximately 66.8% KHP.
To answer these questions, we need to use the concept of stoichiometry and the given equation. Let's break down the steps to find the solutions to the questions.
Question 3: What is the molarity of a NaOH solution if 26.50 mL of it is required to neutralize 0.4150 g of pure KHP?
First, we need to determine the number of moles of KHP used in the neutralization reaction. You can use the formula:
moles of KHP = mass of KHP / molar mass of KHP
KHP (Potassium Hydrogen Phthalate) has a molar mass of 204.23 g/mol. Plugging in the given values, we have:
moles of KHP = 0.4150 g / 204.23 g/mol
Next, we use the balanced equation to relate the moles of KHP to the moles of NaOH. From the equation, we can see that the stoichiometric ratio between KHP and NaOH is 1:1.
Since 26.50 mL of NaOH solution was used, we convert this volume into moles.
moles of NaOH = (volume of NaOH / 1000 L) * molarity of NaOH
Now, we can determine the molarity of NaOH.
molarity of NaOH = moles of NaOH / volume of NaOH (in liters)
Question 4: What is the percentage of KHP in an impure sample of KHP that weighs 0.4200 g and requires 14.00 mL of 0.098 M NaOH to neutralize it?
We need to determine the number of moles of NaOH used in the neutralization reaction. Using the same formula as above:
moles of NaOH = (volume of NaOH / 1000 L) * molarity of NaOH
Next, we use the balanced equation and stoichiometry to relate the moles of NaOH to the moles of KHP. Again, the stoichiometric ratio between KHP and NaOH is 1:1.
We can then determine the number of moles of KHP used and calculate the percentage:
percentage of KHP = (moles of KHP / total moles of sample) * 100
By following these steps, you should be able to find the solutions to the given questions.