A sample of 1.029g of KC8H5O4 was titrated with an NAOH solution of unknown concentration. If 22.83 mL of base was used to reach the endpoint, what was the concentration of NaOH? What mass of KC8H5O4 should be used such that a volume of NaOH between 35-40 mL is needed to reach the endpoint?
Please help, I procrastinated and its due tomorrow!!!
You probably intended this to be potassium hydrogen phthalate which I will rewrite, to make things simpler, as KHP. The H is the hydrogen neutralized by the NaOH.
NaOH + KHP ==> NaKP + H2O.
mols KHP = 1.029 grams/molar mass KHP.
mols NaOH = mols KHP.
mols NaOH = L x M. You know mols and you know L. M is the only unknown.
The second part of the problem is done by working backwards. Using the molarity of the NaOH calculated above, use mols = L x M and plug in , say 38 mL (0.038 L or about half way between 35 and 40). That allows you to calculate mols. Then use mols KHP and mols KHP = grams/molar mass. You know mols KHP and you know molar mass so calculate grams KHP.
To find the concentration of NaOH, we can use the equation:
M1V1 = M2V2
Where:
M1 = concentration of NaOH
V1 = volume of NaOH used (in liters)
M2 = concentration of KC8H5O4 (which is unknown at the moment)
V2 = volume of KC8H5O4 solution used (in liters)
First, we need to convert the volume of NaOH in milliliters to liters, as follows:
22.83 mL = 22.83/1000 L = 0.02283 L
Now, we need to rearrange the equation to solve for M1 (concentration of NaOH):
M1 = (M2 * V2)/V1
Next, we need the molar mass of KC8H5O4, which includes:
K (1 atom) = 39.10 g/mol
C (8 atoms) = 12.01 g/mol
H (5 atoms) = 1.01 g/mol
O (4 atoms) = 16.00 g/mol
Molar mass of KC8H5O4 = (39.10 * 1) + (12.01 * 8) + (1.01 * 5) + (16.00 * 4)
= 204.18 g/mol
Now, we can calculate the moles of KC8H5O4:
Moles = mass / molar mass
For the given sample, mass = 1.029 g, so:
Moles = 1.029 g / 204.18 g/mol = 0.00504 mol
Since the balanced equation is 1:1 between KC8H5O4 and NaOH, the moles of NaOH would be equal to the moles of KC8H5O4.
Now, substitute the values into the equation for M1:
M1 = (0.00504 mol * V2) / 0.02283 L
To find the concentration of NaOH, we need the volume of KC8H5O4 solution used (V2). But it is not provided in the question. So, we cannot solve for M1 (concentration of NaOH) without knowing the volume of KC8H5O4 solution used.
Moving on to the second part of your question, we want the volume of NaOH to be between 35 mL and 40 mL. Let's consider a volume of NaOH as 35 mL for calculation purposes.
Again, we need to convert the volume of NaOH in milliliters to liters:
35 mL = 35/1000 L = 0.035 L
Now, we can rearrange the equation to solve for the volume of KC8H5O4 solution used (V2):
V2 = (M1 * V1) / M2
Again, we need the concentration of NaOH (M1) and the concentration of KC8H5O4 (M2) to find the volume of KC8H5O4 solution used.
Without knowing the concentration of NaOH or the concentration of KC8H5O4, we cannot calculate the mass of KC8H5O4 required.
To solve these questions, you would need more information, such as the concentration of NaOH or the concentration of KC8H5O4, in order to calculate the desired values accurately.