Chem. 112 Final
The blank sample usually contains the solvent from the solution and takes into account the light scattering by the solvent and the cuvette. Transmittance is generally reported as percent transmittance, %T. What is the equation?
%T= I/I0 x 100
This graph shows the titration of 35.0 mL of methylamine solution with a 0.0865 M HCl. Determine the molarity of the methylamine solution.
.0519 M
Potassium hydrogen phthalate (KHP) is often used as a primary standard in acid-base titration. If 20.35 mL of NaOH is required to neutralize 0.382 g of KHP, what is the concentration of the NaOH?
.0919 M
Potassium hydrogen phthalate (KHP, molar mass = 204.22 g/mol) is often used as a primary standard in acid-base titration. If 19.45 mL of NaOH is required to neutralize 0.472 g of KHP, what is the concentration of the NaOH?
.119 M
The concentration of a dilute aspirin solution is 0.000515 M. Standard solutions of this compound were used to prepare a Beer\'s Law plot which gives a slope of 1550.1 M-1. What is the expected absorbance value for the aspirin solution?
.798
third order?
1/M^2*s
second order?
1/m*s
1st order?
1/s
The concentration of a solution can be expressed in a number of ways. Choose the solution expressions that are equal to a solution that contains 1 mg/mL solute. 10^3 g/L 10^-3 mg/microliter 1 g/L 10^-3 microgram/mL 10^3 microgram/mL
10^-3 mg/microliter 1 g/L 10^3 microgram/mL
Calculate the pH for the H3O+ concentration. H3O+ = .01 M
2
You have 87.0 mL of a 0.400 M stock solution that must be diluted to 0.100 M. Assuming the volumes are additive, how much water should you add?
261 mL
How many milliliters of 11.0 M HCl(aq) are needed to prepare 355.0 mL of 1.00 M HCl(aq)?
32.3
Violet light visible spectrum
380 nm - 450 nm
Calculate the molality of a sugar solution that contains 3.94 g sucrose (C12H22O11) dissolved in 285 g water.
4.04 x 10^-2 m
The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. If 0.340 moles of a monoprotic weak acid (Ka = 4.6 × 10-5) is titrated with NaOH, what is the pH of the solution at the half-equivalence point?
4.33
Blue light visible spectrum
450 nm - 495 nm
Green light visible spectrum
495 nm - 570 nm
A buffer solution is made using a weak acid, HA, with a pKa of 4. If the ratio of A- to HA is 10, what is the pH of the buffer?
5
Based upon the absorbance spectrum of Red dye #40, what would be the ideal wavelength to carry out a spectrophotometric experiment on the dye? 13 nm 345 nm 503 nm 587 nm
503 nm
Yellow light visible spectrum
570 nm - 590 nm
Orange light visible spectrum
590 nm - 620 nm
Red Light visible spectrum
620 nm- 750 nm
A specific steroid has λmax = 268 nm and molar absorptivity ε = 11,500 L mol-1 cm-1. What is the concentration of the compound in a solution whose absorbance at 268 nm is A = 0.095 with a sample pathlength of 1.00 cm?
8.3 x 10^-6 M
Absorbance symbol and units
A no units
A student fills a beaker with stock solution, then uses roughly half of the solution in an experiment. After the lab period is over, what should be done with the half of the stock solution that remains unused? A. It should be disposed of in the proper waste container. B. It should be poured back in its original container. C. It should be left out for the instructor to deal with.
A It should be disposed of in the proper waste container.
This is defined as the amount of light that is absorbed by the sample. It is calculated as the negative log of the transmittance, T. What is the equation?
A= -logT = -logI/I0= log I0/I
These are sour, corrosive, capable of changing litmus paper from blue to red, reactive with alkalis.
Acids
Bronsted acid or base? CH3CH2NH3+ CH3CH2O- C6H5OH
Acids: CH3CH2NH3+ C6H5OH Base: CH3CH2O-
Bitter, slippery, changed litmus from red to blue and were reactive with acids
Alkalis (Bases)
Specific protocol should be followed any time a balance is used to weigh the mass of a chemical or object. Select which of the following rules are part of this protocol. A. Glassware must be dried thoroughly before being weighed. B. Glassware, containers, and chemicals should be at room temperature. C. All chemicals should be contained in either a piece of glassware or weighboat. D. The same balance should be used throughout an experiment. E. Filter paper must be completely dry, even after being used in an experiment. A and C only All of the above
All of the above
Which of the following agencies provide research funding that is not federally financed?
American Diabetes Association
A substance that produces an excess hydrogen ions (H+) in aqueous solution
Arrhenius Acid
This is a substnace that ionizes when dissolved in water to yield H+ ions.
Arrhenius Acid
A substance that produces an excess of hydroxide ions (OH-) in aqueous solution.
Arrhenius Base
Substnace that ionizes when dissolved in water to yield the OH- ion
Arrhenius Base
The equation used to calculate the change in freezing point of a substance is delta Tf=Kfm where Kf is the freezing point depression constant and m is the molality of the solution. Which of the following statemetns explains teh correct reasoning for the use of molality rather than molarity in the equation?
As the temperature of a solution changes, its volume will also change, which will affect its molarity but not its molality.
You are measuring the concentration of Fe2 in a sample by measuring the absorbance of its complex with ferroxine. Your sample, measured in a 1.00-cm pathlength cuvette, has an absorbance of 0.280 while the reagent blank in the same cuvette has an absorbance of 0.037. What would be the absorbance reading of these two solutions if measured in a cuvette with 9.00 cm pathlength?
Asample = 2.52 Areagant blank= .33
When preparing a buret for use in lab, the buret must always be cleaned thoroughly. Prior to being filled with solution, the buret is rinsed one last time. What is the buret rinsed with, and why? A. Deionized water should be used to ensure that all of the soap has been removed from the buret. B. The titrant should be used to ensure that when added to the buret it will not be diluted with water. C. Soap should be used to make certain that the buret is completely clean. D. Tap water should be used to rinse all of the soap out of the buret without wasting deionized water.
B- The titrant should be used to ensure that when added to the buret it will not be diluted with water.
A spectrophotometer measures the transmittance or the absorbance, or both, of a particular wavelength of light after it has passed through a liquid sample. Before the transmittance or absorbance of the sample is measured, a cuvette filled only with solvent, called the blank, is placed in the spectrophotometer and measured. Select the reason that, after the blank is measured, the cuvette must be placed in the spectrophotometer in the same orientation each time that it is used. A. The cuvette will only fit into the spectrophotometer in one orientation. B. The transmittance of the cuvette must be measured in the same place each time. C. The spectrophotometer will break if the cuvette position is changed during the experiment. D. The transmittance of the liquid must be measured in the same place each time.
B. The transmittance of the cuvette must be measured in the same place each time.
A= abc
Beer's Law: The absorbance of a sample is directly proportional to the sample concentration, c, and the distance traveled by the light through the sample of path length, b. To equate the abrosbance to the coenntration and path length, the absorptivity constant, a, is used.
when light passes through a light absorbing solution, a portion of the light is absorbed by the solute and another portion is scattered by particles in solution and by the sample holder or ______.
Beer's Law; cuvette
this is an essential step to allow the instrument to subtract the absorption of light by the solvent
Blank Sample
What effect does increasing the concentration of a dissolved solute have on each of the following colligative properties? Boiling point freezing point Vapor pressure
Boiling Point Elevation Freezing Point Depression Vapor Pressure Depression
Any substance that can donate a proton, H+ ion AKA: hydrogen ion donors or proton donors
Bronsted Lowry Acid
Any substance that can accept a proton, H+ ion AKA: hydrogen ion acceptor or proton donors
Bronsted Lowry Base
These are capable of resisting changes in pH --- small amounts of added acid or base are neutralized by buffer compoennets (all of these are conjugate acid base pairs)
Buffered Systems
Which of the following elements is not found in zeolite?
C
Which type of glassware should you use to make the solution (assuming that the accuracy of the concentration is important)?
C
How should the solution be mixed together? A. Fill the container to the 250 mL mark then add the correct amount of stock solution. B. Add the correct amount of stock solution then fill to the 250 mL mark with water. C. Fill the container partially with water, add the correct amount of stock solution, then fill to the 250 mL mark with water. D. None of these are the correct way to mix the stock solution.
C- Fill the container partially with water, add the correct amount of stock solution, then fill to the 250 mL mark with water.
These increase the rate of the reaction by changing the path along which the reaction proceeds. They icnrease reaction rates by lowering the Ea of a reaction. They are present at the start of a reaction and are regenerated by the end of the reaction. They are added to teh reactant mixture and removed from the product mixture
Catalyst
these experiments are conducted in order to gather evidence in support of hypothesized reaction mechanism. The rate f a chemica reaction can be measured by monitoring the change in the concentration of a reactant or product per unit time
Chemical Kinetics
Identify the Lewis Acid and Lewis Base in each of the following reactions: Cl- + AlCl3 ---> AlCl4- BF3 + F- ---> BF4- NH3 + H+ ----> NH4+
Cl- Lewis Base AlCl3 Lewis Acid BF3 Lewis Acid F- Lewis Base NH3 Lewis Base H+ Lewis Acid
The depression of freezing points in solutions by increasing the solute concentration is an exmaple of a ___ _____. These are physical properties or solutions that depends on the number of dissolved solute particles in solution, but not hte identity of the solute.
Colligative Property
You need to determine the concentration of a sulfuric acid solution by titration with a standard sodium hydroxide solution. You have a 0.1722 M standard solution. You take a 25.00 mL sample of the original acid solution and dilute it to 250.0 mL. You then take a 10.00 mL sample of the dilute acid solution and titrate it with the standard solution. You need 15.82 mL of the standard solution to reach the endpoint. What is the concentration of the original acid solution?
Concentration = 1.36 M
During a spectrophotometric analysis of an unknown, you measure your unknown solution\'s absorbance, and the value is higher than the highest standard you used to make your standard curve. What should you do to make sure you can use your standard curve to determine the unknown\'s concentration? A. There is no need to do anything to the unknown solution. Beer\'s Law describes the relationship between absorbance and concentration. This relationship is linear even at high concentrations, so the standard curve equation will apply for any concentration of that specific solution. B.Pour a specified amount of the unknown solution into each of the standard curve solutions. This process will increase the absorbance of the solutions to the point that the unknown solution\'s absorbance will fit within the standard curve appropriately. C. A new set of standard solutions should be made to accommodate the unknown solution concentration. Beer\'s law is linear even at high concentrations, but a new concentration curve should be made to illustrate this point. Even though it is more work, making new standard solutions is a better method of obtaining correct results. D. Dilute the unknown so that it will have an absorbance within the standard curve. Once the diluted unknown concentration is determined, the full strength concentration can be calculated if the dilution process is recorded. Beer\'s Law only applies to dilute solutions, so diluting the unknown is better than making new standards.
D. Dilute the unknown so that it will have an absorbance within the standard curve. Once the diluted unknown concentration is determined, the full strength concentration can be calculated if the dilution process is recorded. Beer\'s Law only applies to dilute solutions, so diluting the unknown is better than making new standards.
How can you experimentally determine the pKa of acetic acid?
Determine the pH of the solution half way to the end-point on the pH titration curve for acetic acid.
Tis is a concept that is simple to udnerstand when considering the freezing point of a substance-
Disorder concept
Molar absorptivity symbol and units
E and L/(mol*cm)
The cell potential can be masuerd by placing a voltemeter between the two electrodes of the voltaic cell and is a measure of how easily electrons flow from one elctrode to another
Ecell
Classify each of the following substances and descriptions as an electrolyte or a nonelectrolyte. Note: If any part of this question is answered incorrectly, a single red X will appear indicating that one or more substances have been placed incorrectly. soluble ionic compound most soluble solutes potassium iodide, KI a substance that forms an aqueous solution that does not conduct electricity sodium hydroxide NaOH sodium chloride, NaCl Methanol CH3OH Table Sugar
Electrolyte: soluble ionic compound sodium chloride potassium iodide sodium hydroxide Non: most molecular solutes table sugar methanol, CH3OH substance that forms an aqueous solution hat does not conduct electricity
This is the driving force for electrons to mvoe from one electrode to the other and is expressed in units of volts
Electromotive force or cell potential
This is when a change that indicates equivalence is observed in the analyte solution
End point of titration
This is reached when chemically equivalent amounts of acid and base are reacted. The change in pH becomes very rapid here and it is important to add the titrant in smaller amounts as the observed pH starts to increase faster.
Equivalence Point
This is the temperature at which the solution becomes saturated -- the lowest temperature at which the solvent is still a liquid
Eutectic temperature
An effective way to test the amount of red dye in an aqueous solution is to measure the amount of red light (620-750 nm) absorbed by the solution.
False
The cage size of the zeolites is in cm scale.
False
The idea of further converting the zeolite to be magnetic is to make the zeolite more stable.
False
Zeolites theoretically can be made magnetic by adding sodium ion to them.
False
these are designed to produce a current, generated from the transfer of electrons in a redox raction that can be used to do work -these use sponteanous redox reactions to transfer chemical energy into elecrical energy they consist of two compartments: anodic half cell and cathodic half cell
Galvanic or Voltaic Cells
Assuming equal concentrations and complete dissociation, rank these aqueous solutions by their freezing points. Li3PO4 NaNO3 Na2SO$
Highest: NaNO3 Na2SO4 Lowest: Li3PO4
Experiment 8
In this experiment, chlorophyll-a is extracted from a spinach leaf is isopropnaol. The concentration of extracted chlorophyll-a in isopropanol solution is determined spectrophotometrically, and the mg chlorophyll-a per g spinach is calculated.
How would the following events affect the rate of the following general reaction? A+BC-- ABC
Increase: Increasing the conentration of A adding a catalyst increasing the temperature Decrease: decreasing concentration of BC
These react over a range of pH, they cannot exactly pinpoint the equivalence point. These are used to determine the endpoint at which the ____ changes color.
Indicators
This is where the curve changes from a positive to a negative slope. It is also the largest change in pH per change in volume as can be seen when the change in pH/change in volume vs the volume of teh titrant is added.
Inflection Point
What were the limitations to the Arrhenius theory?
It did not account for observed acid base behavior in nonaqueous solutions. It did not explain the fact that many compounds containing hydrogen did not provide an acidic solution when dissolve in water. It did not classify bases that did not contain OH-, did not explain why substances like Na2CO3 behaved like bases, or why hydrogen containing compounds such as NaHCO3 did as well.
Which of the following is true of an isosbestic point?
It is a point on an absorption spectra where two species have the same molar absorptivity.
The following experimental data was collected during a freezing point depression study. Use this data to determine Kf for BHT (butylated hydroxytoluene).
Kf for BHT = 6.83 degress C/m
Electron pair acceptor Ex: BF3
Lewis Acid
Electron Pair donor Ex: NH3
Lewis Base
Lowest energy photons have a ____ frequency, and a ______ wavelength.
Lower frequency Higher wavelength
Units for k at zero order?
M/s
The Ka values for several weak acids are given below. Which acid (and its conjugate base) would be the best buffer at pH = 6.0?
MES; Ka = 7.9 × 10-7
A spectrophotometer measures the transmittance or the absorbance, or both, of a particular wavelength of light after it has passed through a liquid sample. Before the transmittance or absorbance of the sample is measured, a cuvette filled only with solvent, called the blank, is placed in the spectrophotometer. Select the following step that is NOT necessary to complete before a cuvette is placed into the spectrophotometer.
Make sure the cuvette has exactly the same amount of solution so the readings are consistent.
How should the correct amount of stock solution be obtained? -Measure out x mL using a graduated cylinder - Measue out x mL using a volumetric pipet - measure out x g on a balance
Measure out x mL using a volumetric pipet
______ _____ & ____ can be used for the analysis of a strong acid by a strong base.
Methyl red & phenolphthalein
This describes the number of moles per solute per kilogram of solvent. (engineers prefer this)
Molality
The composition of the solution varies the amount of solute dissolved in solution. One way to express concentration is mass of solute per volume of solution, AKA _________ (M)
Molarity
Determine the concentrations of Na2CO3, Na , and CO32- in a solution prepared by dissolving 2.50 × 10-4 g Na2CO3 in 2.50 L of water. Express all three concentrations in molarity. Additionally, express the concentrations of the ionic species in parts per thousand (ppt). Note: Determine the formal concentration of CO32-. Ignore any reactions with water.
Na2CO3= 9.43 x10^-7 Na += 1.89 x 10^-6 M= 4.32x10^-5 ppm Co32-= 9.43x10^-7 = 5.66 x10-5 ppt
For each reaction, identify the precipitate or lack thereof. 2NaCl (aq) + Ba(OH)2 aq ---> BaCl2 +2 NaOH AgClO3 (aq) + MgI2 (aq) ---> AgI + Mg(ClO3)2
No precipitate AgI
Consider the steps involved in preparing a dilute solution from a stock solution. Rank them in order from first to last.
Obtain a flask that is thoroughly cleaned and dried. Add the desired amount of stock solution. Add deionized water until the volume reaches the mark on the flask. Cap the flask and invert several times to thoroughly mix the solution.
A substance that can donate a hydrogen ion to another substance A substnace that can accept a hydrogen ion from another substance
Other
What is the risk in filling chemical waste containers past the recommended level?
Overflowing waste containers can lead to drips of potentially hazardous chemicals down the sides. Chemicals and their vapors need room to expand in case of increased temperatures. When overfilled containers are moved or transported, chemicals can easily splash out.
This is the loss of electrons
Oxidation
Which is the correct method for drawing liquid into a pipet?
Place a pipet bulb at the top of the pipet to draw up the liquid
the path that a particular reaction takes
Reaction mechanism
Determine the correct sequence of steps used in carrying out a measurement using a pH probe. Rank them in order from first to last.
Remove probe from solution Rinse probe with deionized or distilled water and blot dry Place probe in solution to be measured Observe readout on meter of sample solution pH Rinse probe, blot dry, then place in storage solution
This is the amount of salt dissolved in a sample of water. This is typicalyl reported in grams salt per liter sample or ppt. NaCl is the most abundant in seawater. (g NaCl/ g salt water x 100)
Salinity
All other components are _______.
Solutes
A _____ is a homogenous mixture composed of two or more components.
Solution
The component in the largest amount is called the _____ (isopropanol, for example).
Solvent
If a student accidentally adds deionized water past the calibrated mark on the volumetric flask, he should: -Dump the excess solution until the volume is right at the mark - Start over and make an entirely new solution
Start over and make an entirely new solution
Under certain conditions the temperature of a solution can be lower than the eutectic temperature without further precipitating the solute from the solution this is a ______ _____
Supersaturated solution
An effective way to test the amount of red dye in an aqueous solution is to measure the amount of green light (495-570 nm) absorbed by the solution.
TRue
A=Ebc
The absorptivity constant is both solute and wavelength specific. When we use molarity (mol/L) to express concentration, the absorptivity is renamed the molar absorptivity (e). Rewritten version of Beer's LAw
What condition(s) must occur when a chemical reaction is at equilibrium?
The forward and reverse reactions are happening at equal rates
How does a buffer resist change in pH upon addition of a strong acid?
The strong acid reacts with the weak base in the buffer to form a weak acid, which produces few H ions in solution and therefore only a little change in pH.
Why should these selected rule(s) be followed?
There may be discrepancies in accuracy between individual balances. A residue left on the balance will contaminate the balance pan surface and anything that comes into contact with it afterwards. Weighing wet items will cause the displayed mass to be greater than the actual mass of the object. Objects at any temperature other than room temperature can create air currents which can affect the balance pan, causing the measured mass to be higher or lower than the true mass.
Fajan's Method
This is used to determine chloride ion concentration in the experiment, relies on the use of an adsoption indication, dichlorofluorescein.
Laboratory method which involves the adding of a known amount of acid to react with an unknown amount of base, or vice versa so that the unknown amount of base or acid can be quantified. These can be used to make the measurement of exact proton concentration or the acidity in a chemical system
Titrations
Zeolites have structures that contain \"cages\" which are ideal for absorbing materials.
True
Research funding is often obtained by preparing and submitting a grant proposal to a government agency. Decide if the following statements regarding this process are true or false. Agencies typically award funds based upon which proposals are deemed the best investments. A proposal that has been submitted is virtually guaranteed to be awarded funding.
True False
What concentration of ClO3- results when 645 mL of 0.587 M AgClO3 is mixed with 763 mL of 0.801 M Mn(ClO3)2?
[ClO3-] = 1.14 M
A different sample of Compound X in the same solvent has an absorbance of 0.524 at 528 nm when measured with the same cuvet. What is the concentration of this second sample?
[X] = 1.14 x 10^-4 mol X/ L
2A + 3B--- products What is A's order? B's? Overall?
a-0 b-2 overall-2
The ____ degree of buffering occurs where the desired pH is equal to the pKa or the point where the coentrations of ....
acidic compoennt equals the conentration of the basic compoenent
molecules must collide with a certain minimum energy (_____ _______) Ea, in order to react
activation energy
Which of the following factors will influence the rate of a chemical reaction? Selec
adding a catalyst changing the concentration of reactants the nature of reactants changing the temperature
oxidation occurs in the
anodic half cell
Titrations using silver nitrate, __ _____ are precipitation titrations.
argentometric titrations
Path length symbol and units
b cm
In order to safely run a sample in a centrifuge, it is important to
balance the sample with a counterweight of the same mass directly across from it.
What are other colligative properties?
boiling point elevation, vapor pressure lowering, and osmotic pressure
concentration symbol and units
c mol/L
these are the data points representing solutions of known concentration are called a ______ curve or ________ curve
calibration curve standard curve
reductions occurs in the
cathodic half cell
These are brightly colored adsorbent species or precipitates have been deemed to aid in endpoint determination
chemical indicators
species that are both produced and consumed during reaction
chemical intermediates
Chlorophylls strongly absorb light because of the _______ and ____ of alternating single and double carbon-carbon bonds, mainly in the nitrogen containing ring that surrounds and bnds the Mg2+ ion, as shown above.
conjugation and resonance
Consider what would happen if absorbance was monitored rather than percent transmittance in the scenario above. Upon removal of the clay, the measured absorbance should _____________
decrease
A 0.0000796 M sample of Compound X in a solvent has an absorbance of 0.384 at 528 nm in a 1.000-cm cuvet. The solvent alone has an absorbance of 0.058. What is the molar absorptivity of Compound X?
e= 4.10 x 10^3 M-1*cm-1
A voltmeter is primarily used to measure
electrical potential
for _____, solutes that dissociate or ionized when dissolved in water, the number of moles of particles per formula unit in solution is greater than nonelectrolytes
electrolytes
the individual reactions are known as
elementary reaction
Bentonite clay sequesters PAHs by the formation of permanent covalent bonds.
false
This is a colligative property that is partially responsible for the survival of cold tolerant species
freezing point depression
The highest energy photons have a _______ frequency and a ______ wavelength.
higher frequency lower wavelength
The percent transmittance of a solution of Procion Red is measured. If adding bentonite clay were to sequester dye molecules from solution, then upon removal of the clay the measured percent transmittance should ____________
increase
If a compound is blue in color...
it absorbs orange light
Percent difference equation?
known-experimental/known x 100
a rate law can be determined experimentally using the
method of initial rates
this is the moles solute per kg solvent
molality
this can be determined by measuring the degree to which a known mass of the solute depresses the freezing point of a known mass of solvent
molar mass
Which of the following represent basic research? Select all that apply.
n investigation into the mechanism of a metal catalyst a multi-step synthesis of a natural product observation of the biosynthetic pathway of vitamin A
the species being reduced
oxidizing agent
The mathematical definition is the negative log of the H3O+ concentration
pH
To monitor the extent of the reaction between acid and base, the pH is monitored with either a _____ or _____.
pH meter or colorimetric indicator
Calculate the pH for the H3O+ concentration. H3O+ = 1.0 x 10^-11 M
pH= 11
Calculate the pH for the H3O+ concentration. H3O+ = 1.0 x10^-8 M
pH= 8
What two factors determine the pH that a specific buffer system can maintain?
pKa and the relative concentration sof the basic & acidic components
These are weight comparisons (environmental scientists favor this)
ppm (parts per million) ppb (parts per billion)
symbolized as K; can have different units depending on the reaction order
rate constant
this is temperature dependent and increases with increasing temperature
rate constant
the overall rate law of a reaction is therefore determined by the slowest step or the ___ _____ _____
rate determining step
a formula that relates reactant concentration to the reaction rate
rate law
always has units of amount per time (M/s)
rate of reaction
this can be described by the rate constat, k -the larger the rate constant, the faster the reaction
rate of reaction
electrons are transferred from the
reducing agent
Thi sis the reduction in charge or gain in electrons
reduction
During operation, which half-reaction occurs at the cathode in each type of cell. Battery (galvanic) electrolytic cell
reduction occurs at the cathode reduction occurs at the cathode
This links thetwo cells to preent a build up of excess charge in eitehr cell
salt bridge
Any spontaneous change occurs with an increase in the entropy of the universe
second law of thermodynamics
The convention is to measure all reduction potentials of standard solutions relative to that of __ ______ ____
standard hydrogen electrode
1 M 1 atm 25 degrees
standard solutions
a spontaneous change is a change that occurs with no outside intervention; the universe is defined as the system and its ______
surroundings
electrolyte filled
this type of salt bridge suports the flow of ions from one cell to the other without the two solutins to mix, maintaining charge balance
This can be generated from these data pairs by plotting the pH on the y axis versus the volume of titrant on the x axis.
titration curve
______ : This is calculated by dividing the light intensity, I, that passes through the solution by the light intensity that passes through a blank sample, Io.
transmittance
amount of light that passes through a sample can be measured at a given wavelength, lambda, by a spectrophotometer as either _____ or _____
transmittance or absorbance
PAH is an acronym for polycyclic automatic hydrocarbon.
true
PAHs interact with bentonite clay by intercalating into the pores.
true
You need to prepare 250.0 mL of a 1.50 M HCl solution from a 3.00 M HCl stock solution. Based on your answer above, what is the value of x?
x= 125