NAME and ID Number:
Lab Partner:
Quiz Section: AM
Total Points
= 60
PURPOSE AND METHOD
DATA AND CALCULATIONS
A.
Standardization of NaOH
Run 1
Run 2
Mass of KHP
0.13
0.13
moles KHP
0.000651
0.000651
Initial buret reading, mL
3
3
Final buret reading, mL
9.4
9.54
mL NaOH titrated
6.4
6.54
L NaOH titrated
0.01
0.01
[NaOH], moles/L
0.1018
0.0996
Average, [NaOH]
0.1007 M
4 pts
Table 1:
NaOH Standardization
How are the solubility products (K
sp
) of KHP at various temperatures determined? (
4 pts
)
From the chemical equation: KHP (s) <> K+(aq) + HP (aq), the Ksp can be determined by multiplying the concentration of [K+] and the
[HP]. Since we know that the K and the HP are in a one to one ratio, if we find one of the concentrations then we can use that same one to
call the other concentration. With out experiment we can determine the concentration of HP from the titration of KHP with NaOH. Since from
part A we will determine the concentration of NaOH, we can use that information along with the amount of NaOH used to reach equilibrium
to determine the mmoles of HP. This value will then be divided by the volume of KHP that was used in that process.
How
is K
sp
in a saturated solution of KHP in 0.50 M KCl determined?
(4
pts
)
Once the saturated solution is made, we will measure its intensity using the flame photomet er
We can
derive the concentration of K using
the linear regression line created from the intensity of the the known concentrations.
To determine the concentration of K, we would
subtract the yintercept from the intensity and divide that number by the slope of the linear regression line.
Since this solution is created by
the dilution of K by a factor of 2500, we will divide the concentration that we get from the graph by 2500 to get the original concentration of
K.
To determine the concentration of the base, we will titrate a total of three times
3mL of
the solution of KCL in KHP. The amount of
NaOH used to titrate this solution multiplied by the average concentration of NaOH determined from part A will give us the concentration of
OH.
EXPERIMENT 4: THERMODYNAMICS II
THE TEMPERATURE DEPENDENCE OF THE SOLUBILITY PRODUCT, HEAT OF
SOLUTION, AND ENTROPY OF SOLUTION OF POTASSIUM HYDROGEN PHTHALATE
By signing below, you certify that you have not falsified data and that you have not plagiarized any part of this lab report.
Signature:
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '08
 Chiu
 Chemistry, Linear Regression, pH, Solubility

Click to edit the document details