A 2.685 g sample of KHC8H4O4 was dissolved in water and uses to standardize a NaOH solution. The endpoint was reached after 38.25mL of titrant were delivered. Find the molar concentration of the NaOH solution.
To find the molar concentration of the NaOH solution, we first need to calculate the number of moles of KHC8H4O4 in the sample.
Given:
Mass of KHC8H4O4 sample = 2.685 g
We can find the molar mass of KHC8H4O4 using the periodic table:
The molar mass of K (Potassium) = 39.10 g/mol
The molar mass of H (Hydrogen) = 1.01 g/mol
The molar mass of C (Carbon) = 12.01 g/mol
The molar mass of O (Oxygen) = 16.00 g/mol
The molar mass of KHC8H4O4 can be calculated as follows:
Molar mass = (39.10 g/mol) + (1.01 g/mol * 8) + (12.01 g/mol * 8) + (16.00 g/mol * 4)
Now, let's calculate the molar mass of KHC8H4O4:
Molar mass = (39.10 g/mol) + (8.08 g/mol) + (96.08 g/mol) + (64.00 g/mol)
= 207.26 g/mol
Next, we need to determine the number of moles of KHC8H4O4 in the sample using the given mass and molar mass:
Number of moles = Mass / Molar mass
= 2.685 g / 207.26 g/mol
Now, let's calculate the number of moles of KHC8H4O4:
Number of moles = 0.01294 mol (rounded to 5 decimal places)
Since the balanced equation for the reaction between NaOH and KHC8H4O4 is 1:1, we know that the number of moles of NaOH used in the reaction is also 0.01294 mol.
Now, we can use this information to find the molar concentration of the NaOH solution:
Molar concentration of NaOH = Number of moles / Volume of NaOH solution
= 0.01294 mol / 0.03825 L
Finally, let's calculate the molar concentration:
Molar concentration of NaOH = 0.3387 mol/L (rounded to 4 decimal places)
Therefore, the molar concentration of the NaOH solution is approximately 0.3387 mol/L.
To find the molar concentration of the NaOH solution, we can use the concept of stoichiometry and the equation:
KHC8H4O4 + NaOH → KNaC8H4O4 + H2O
First, we need to determine the number of moles of KHC8H4O4 used. To do this, we use the given mass of KHC8H4O4 and its molar mass.
Molar mass of KHC8H4O4:
K: 39.10 g/mol
H: 1.01 g/mol (x 8)
C: 12.01 g/mol (x 8)
O: 16.00 g/mol (x 4)
Molar mass of KHC8H4O4:
39.10 + 1.01(8) + 12.01(8) + 16.00(4) = 204.22 g/mol
Number of moles of KHC8H4O4 = mass / molar mass
Number of moles of KHC8H4O4 = 2.685 g / 204.22 g/mol
Next, we need to determine the number of moles of NaOH used. Since we know the volume of NaOH solution delivered (38.25 mL) and its concentration is what we are trying to find, we can use the balanced equation to relate the moles of KHC8H4O4 and NaOH.
From the balanced equation, we see that the stoichiometric ratio between KHC8H4O4 and NaOH is 1:1. Therefore, the moles of NaOH used is the same as the moles of KHC8H4O4 used.
Number of moles of NaOH = Number of moles of KHC8H4O4 = 2.685 g / 204.22 g/mol
Finally, we can calculate the molar concentration of the NaOH solution.
Molar concentration of NaOH = moles of NaOH / volume of NaOH solution (in L)
Molar concentration of NaOH = moles of NaOH / (38.25 mL * 1 L/1000 mL)
Note that the conversion factor used in the denominator is to convert mL to L.
Substituting the values we found:
Molar concentration of NaOH = (2.685 g / 204.22 g/mol) / (38.25 mL * 1 L/1000 mL)
Molar concentration of NaOH = 0.01311 mol / 0.03825 L
Molar concentration of NaOH = 0.342 mol/L
Therefore, the molar concentration of the NaOH solution is 0.342 mol/L.