Chem lab practicum

If you plot the concentration of crystal violet vs time and get a negative linear slope, what is the expected order of the reaction in [crystal violet]

0th order

What size volumetric flask will you use to then make your collected solution to a known volume? exp 2

100.0 mL

What is the molar ratio between Ca2+ and EDTA

1:1

If you plot the natural log of the concentration of crystal violet vs time on a graph and get a negative linear slope, what is the expected order of the reaction in [crystal violet]

1st order

How many acidic hydrogens does neutral Eriochrome black t indicator have

2

If you perform cation-exchange chromatography on a solution contains Mg2+ ions, how many moles of H+ ions will be displaced by 1 mole Mg2+

2

what will be the pH of the three solutions you will use (8)

2.0, 7.0, 11.0

You are trying to titrate to neutralization 10.00 mL of a .2 M monoprotic acid using 0.1 M sodium hydroxide and phenolphthalein as an indicator. About how much NaOH do you expect it to take?

20.00 mL of NaOH

If you perform cation-ion exchange chromatography on a solution containing Fe ions, how many moles of H+ ions will be displaced by 1 mole Fe

3

In this weeks Ka experiment spectrophotometric analysis is being used. What is the range wavelength that you will need your solutions over

350 nm to 700 nm

How many acidic hydrogens does neutral EDTA have

4

What is the expected max wavelength range for a solution that is yellow in color

425-450

What would be the expected conductivity of Tap water

554

what is the expected max wavelength range for a solution that is blue

600-650 nm

What is the molar ration S2O3 with respect to IO3

6:1

what would be the expected conductivity of DI water

7

Which of these solutions will make it possible to determine H2O (8)

7.0; the buffered solution

How will you determine the Absorbance in order to solve the above equation? (8)

ABS vs wavelength of all three solutions

To make a calibration curve of a series of dilution what do you need to plot?

Absorbance vs concentraion

What are the two things that was plotted in exp 9

Absorbance vs wavelength

What mobile phase will be used in Part 1 of the TLC separation

Acetone, 50:50 acetone pet ether; 20:80 acetone pet ether

What does the term Ka mean

Acid dissociation constant

After your sample of Ca2+ water is passed through the resin what type of analysis will be done? (exp 2)

Acid/base titration or volumetric analysis

What was the lewis acid in exp 2

Ca2+

What are example of Lewis acids that we have used in lab so far

Ca2+, Ni3+, Cu2+

What is the observed color change when you use phenolphthalein as an indicator when titrating with a base

Colorless -> pink

What would you expect the color change to be if we used phenolphthalein as our indicator when NaOH is added to our H+ solution

Colorless -> pink

What two metals are you analyzing in exp 3

Cu and Ni

Give the definition of Rf (retention factor) for the TLC separations

Distance the spot travels, distance the mobile phase travels

What is the defining characteristic of a lewis acid

Electron pair acceptor

What is the defining characteristic of a lewis base

Electron pair donor

Look up other types of chromatography and list them

Gas chromatography; gel electrophoresis; HPLC

How are these types of chromatography different from the two types you are using?

Gas is the mobile phase for GC; electricity is mobile phase for electrophoresis; high pressure liquid chromatography is used under pressure

After adding 20.00 ml of Ca2+ water solution to a column that has cation-exchange resin in it. What would you expect to be the eluate in this separation

H+

what is the HOMO in terms of MO theory

Highest occupied molecular orbital

Why do you only want to use a pencil to mark your TLC plates

Inks can be dissolved and travel with mobile phase

What does it mean if a ligand is bidentate

It has two donor atoms and can bind to the central metal ion at two points

A cation ion-exchange column is not regenerated after being used. How might this affect the Ca2+ determination for the next set of students

It is possible that not enough H+ remains on the column to exchange with all of the Ca2+ in the next students sample and the calculated concentration of Ca2+ would be lower than the actual

what is the primary standard used for the redox titration

KIO3

what are the units of the molar absorptivity constant in the kinetics experiment

L/mol x cm

What is the LUMO in the terms of MO theory

Lowest occupied molecular orbital

What does each symbol represent in the q = mC(delta)T

Mass (g), change in temperature,

What was the secondary standard used for the redox titration

Na2S2O3

What is the standard used in your exp 2 analysis

NaOH

If you perform anion-exchange chromatography on a solution contains Cl ions, what will be your eluate

OH-

If you perform ion-exchange chromatography, with anion-exchange resin, on a solution containing Cl-ions what ions will be in your eluate

OH-

What indicator did you use in the ion-exchange chromatography

Phenolphthalein

What is the indicator used in exp 2 analysis

Phenolphthalein

What fundamental process is the separation based on for both of these types of chromatography

Polarity

what color change do you see when you add NaOH to crystal violet

Purple -> colorless

If there are three protons on a carbon atom adjacent to a CH2 group, what would you expect the splitting/multiplicity of the CH2 group to be

Quartet

What is the observed color change when you use Eriochrome Black T as an indicator

Red -> blue

List the compounds (dyes) you will use for the TLC separations

Rhodamine B, Erthrosin B, Sudan black B

What stationary phase is used for your column chromatography separations?

Silica

You are doing an acid-base titration and phenolphthalein is your indicator, where should acid and base be

The base should be in the buret, the acid should be in flask

If you cool the solutions of both NAOH and crystal violet below room temperature, how would you expect the rate of color change to be compared with the rate using room temperature solutions

The color change will occur more slowly

if all the HCl was not properly rinsed out of the cation-exchange column, how would that effect the concentration of Ca2+

The concentration of Ca2+ would appear to be higher

What would happen if you added the starch too early in the redox titration

The starch-I3 complex would not be able to react with the thiosulfate and un-complex and the solution would not turn colorless

If the solution turns red when using the Eriochrome Black T as your indicator what does that mean?

There are metal ions in the solution

If the solution turns blue when using eriochrome black t as your indicator, what does that mean

There aren't any metal ions present

If the solution turns blue when using eriochrome black t as your indicator what does that mean? (1)

There aren't metal ions that would bind with eriochrome black t

If the solution turns red when using eriochrome black t as your indicator what does that mean

There is Ca2+ and Mg ions present

When regenerating the cation ion-exchange column, you add an excess of HCl. If the column is not rinsed enough to remove any excess H+ how would this affect the calculated Ca2+ moles of the next group

There would be an excess of H+ along with the H+ from the Ca2+ added to the column resulting in a higher calculated result then actual

What types of chromatography will you be performing in this experiment

Thin layer and column

What is the purpose of adding the buffer solution to the Ca2+ solution

To deprotionate the acidic hydrogens in the EDTA so they can bind to Ca2+

What were the techniques used in last week's lab (exp 2)

Volumetric analysis and chromatography

What data will you be measuring and recording in this experiment (8)

absorbance at different wavelengths

When is the pKa = pH

at the 1/2 equivalence point

what are the colors of bromothymol blue in basic and acidic conditions

blue and yellow

What indicator will you be analyzing? (8)

bromothymol blue

What type of ion-exchange will you be performing (exp 2)

cation-ion exchange

If the reaction between a metal ion and a ligand gave off heat what would be the expected sign of delta H be and is the reaction endothermic or exothermic

delta H negative, exothermic

What is the slope of the Beer's Law calibration curve equal to

e x l

What are examples of Lewis bases that we have used in lab so far

eriochrome black t, EDTA, ethylenediamine

In the thermochemistry lab what should your final units be

kJ x mol-1 of metal ion

What is the color of phenolphthalein in basic conditions

magenta

List the compounds (dyes) used for the column chromatography

methylene blue, fluoresessin

What is the indicatory used in the potentiometric titration

phenolpthalein

What indicator will you use in the redox titration

starch

What are the two phases that each type of chromatography have?

stationary and mobile phase

What is the purpose of the indicator in a titration

to find the moles of an unknown by seeing the endpoint of a reaction

The reaction between metal ions and ligands is an example of a lewis acid-base reaction

true