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Flashcards in Chemistry exam 25.05-2016 Deck (16):
1

General Chemistry – Short Questions
1. Write the Nernst for Cu2+/Cu electrode

The Nernst equation for an electrochemical half-cell is:

E = E⊖ − (RT/nF) lnQ
E = E⊖ + (RT/nF) ln (aRed/aOx)

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2. Give 3 stabilizing factors for colloids

- Electrical charge
- Hydration (solvation)
- Protective colloids

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3. Give 4 examples of Chromatography that use the physical-chemical method of separation

- Adsorption chromatography
- Partition chromatography
- Ion exchange chromatography
- Gel chromatography

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4. Write the second law of Thermodynamics

Entropy is “nearly” conserved, which means any decrease of entropy in a given region of space is almost balanced by an increase in another region. In an isolated system, the entropy never decreases.

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5. Explain/write the equation for the relationship between Gibbs Free Energy and the Equilibrium Constant

∆G0 = -RTln(K)

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6. Write Avogadro’s Law

Equal volumes of any two gases at the same temperature and pressure contain the same number of molecules.

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7. Write the Ideal Gas Law

PV=nRT

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8. Give three postulates of the Kinetic Gas Theory

1) Gases are composed of molecules whose size is negligible compared to the average distance between them

2) Molecules move randomly in straight lines in all directions and at various speed. They collide each other and with the wall of the container

3) The average kinetic energy of the molecules of a gas depends upon the temperature

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9. Write Henry’s Law

The solubility of a gas I proportional to the partial pressure of the gas above the solution.

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10. Define/write the equation for Osmotic Pressure

Osmotic pressure π: Equal to the pressure that when applied to the solution
just stops osmosis
π = c. R. T
c = concentration (mol/dm3)
R = ideal gas constant
T = abs. temperature (Kelvin)

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11. Explain the Enthalpy change for KCl aqueous solution

...

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12. Name 2 surfactants

Soap and toothpaste

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3. Draw/name 3 alkaloids and 3 terpenes

Alkaloids: Nicotine, Coniine, Caffeine
Terpenes: Menthol, Phytol, Vitamin A (retinol)

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7. Write the reaction equation of the formation of a nucleotide

Nucleosides + Phosphoric acid →
nucleoside-5’-phosphate = nucleotide

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8. Name 3 examples aroma agents

Umami,
Miraculin,
Curculin,
L-glutamic acid

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9. Name 3 examples of mycotoxins

Ochratoxin A,
Trichothecenes,
Aflatoxin