Exams 1-4 Flashcards Preview

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Flashcards in Exams 1-4 Deck (49):
1

A reaction is favored when K is ___more/less___ than 1.

more

2

If two rxns are added, the new K is the ___sum/product___ of the two individual values.

product

3

If Q>K, then the rxn favors the ___reactants/products___.

reactants

K

4

Solubility product is the __________ constant for the rxn in which a solid dissolves to give its constituent ions in solution.

equilibrium

5

A salt will be ___less/more___ soluble if one of its constituent ions is already present in solution?

less

6

___Smaller/Larger___, more highly charged ions bind more water molecules and behave as larger species in soluction.

smaller

7

The greater the ionic strength of a solution, the ___larger/smaller___ the charge in the ionic atmosphere.

larger

8

The activity coefficient measures the deviation of behavior from __________.

unity

9

As ionic strength increase, activity coefficient ___increases/decreases___.

decreased

10

Identify the acid, base, conjugate acid and conjugate base:

1. HCO3- + HF H2CO3 + F-


2. HCO3- + OH CO3^2- + H2O

1.
Acid = HF
Base = HCO3-
CA = H2CO3
CB = F-


2.
Acid = HCO3-
Base = OH
CA = CO3-
CB = H2O

11

Explain the relationship between ionic strength and unity of a solution.

The higher the ionic strength the farther the solution is from unity.


Ionic strength is *inversely proportional* to UNITY

12

When the concentration of acids or bases is lower than 10^-7, the ___________ of water governs the pH.

autoprotolysis

13

A _____________ is a mixture of a weak acid and its conjugate base.

buffer

14

Buffer capacity ___increases/decreases___ as the concentration of the buffer increases.

increases

15

A zwitterion is an amino acid which has both ______ and _______ sites.

positive and negative

16

Water is an example of an __________ species.

amphiprotic

17

A buffer made from a diprotic ( or polyprotic ) acid is treated in the same was as a buffer made from a __________ acid.

monoprotic

18

The strongest acid that can exist in water is the ________ ion.

hydronium

19

Because of the _______________. HLCO4 and HCL have the same acid strength.

leveling effect

20

How does he leveling effect change when a weak acid is used as the solvent?

For example, explain the difference of strength of HCLO4 versus HCL in water as a solvent or acetic acid as solvent.

In water, both HClO4 and HCl will have the same pH because there is only so much water to dissociate.

In acetic acid, the strength of the HClO4 vs. HCl would matter as they are reacting w/ the acidic solvent so the stronger acid would end up having a bigger effect. (HClO4)

21

What is the difference between the equivalent point and end point?

Equivalent point = Theoretical

End point = experimental

22

Metal ions act as lewis _______.

acids

23

A battery is dead at __________.

equilibrium

24

EDTA is an example of a _________ ligand.

complexometric

25

A titration based on complex formation is called __________ titration.

complexometric

26

Water is an example of an __________ species.

amphiprotic

27

A ___________ agent binds the metal strongly enough to prevent metal hydroxide.

auxiliary

28

A _________ cell uses a spontaneous rxn to generate electricity.

galvanic (voltaic)

29

The ___smaller/larger___ the voltage the more current will flow.

larger

30

Electrons flowing away from S.H.E. give a ___positive/negative___ voltage.

positive


SHE e-------> = +voltage

31

What is the purpose of dissolving a metal like Fe in an acidic solvent?

to prevent it from binding to a hydroxide

32

How are standard reduction potentials found, i.e. what is used and what kind of set up does it consist of?

Standard Hydrogen Electrode

(S.H.E.) is set up on one side of galvanic cell and metal on other side and the standard reduction potential is the voltage flowing to or from the S.H.E.

33

What is the purpose of an auxiliary agent?

auxiliary agents bind to metals to prevent metal hydroxide formation but allows y^4- to bind to the metal.

(i think y^4- is EDTA)

34

What is the difference between end point and an equivalence point?

At equivalence pt. there is an equal amount of moles of products and reactants

At endpoint there is more reactants

35

Spectroscopy is any technique that uses _______ to measure chemical conditions.

light

36

The radiational transition S1 ---> S0 is called ___________.

fluorescence

37

Radiational transition T1 ---> S0 is called ___________.

phosphorescence

38

A ____________ lamp is an excellent source of continuous visible and near-infrared radiation.

tungsten

39

A ___________ is a wavelength selector.

monochromator

40

Gaussian noise is also called ___________.

white noise

41

Lasers provide isolated lines of a single __________ for many applications.

wavelength

42

Energy is directly proportional to ____________.

fluorescence

43

Explain how amplification of the signal is achieved in the ELISA immunoassay:

The enzyme bound to antibody catalyses a rxn infinitely as long as the correct reactant (substrate) exists so it amplifies the signal

44

Why does the wavelength_0 transitions in absorption and emission not exactly overlap?

Stoic shift

45

What two criteria are needed for a LASER?
Explain each.

Population inversion: more molecules are at E2 energy level than any other (E1, E3, E0), so it stays at a decently high energy level.


Stimulated Emission: molecules going down in energy level release a photon which hits another molecule that causes it to lose a photon q and so on... this effect is made larger by population inversion

46

1. What is the purpose of a detector?
2. What does sensitivity mean when referring to a detector?
3. Which part of the body is more sensitive than a photomultiplier tube?

1. Detectors detect photons and turn that into an electrical current that can be read.

2. Sensitivity refers to the ability to detect very small energy, as in single photons for example.

3. Rods in the eyes are more sensitive

47

Why is it more advantageous to use a laser instead of a lamp for a light source? What would be the disadvantage?

Advantages: lasers are brighter, only produce one wavelength and no stray light effect

Disadvantage: very expensive

48

Which cuvet is best suited for biological samples and why?

Microliter cuvette, because samples are very small

49

List the deviations from Beer's Law:

1. polychromatic light (only applies to monochromatic)

2. non-dilute solutions (only applies to dilute < 0.01M)

3. It fails if the analyte undergoes a chemical change and the product of this change has a different spectrum than the original analayte.



***Beer's law fails when deviations from the proportionality between measured absorbance and concentration occur***