Lab 1 Flashcards

1
Q

what is the name of the reaction

A

BR Oscillation Reaction

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2
Q

what will the solutions display when they are mixed

A

chemical oscillation

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3
Q

what is a solution

A

homogenous mixture consisting of two or more substances in a single phase

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4
Q

what is a solute

A

substances that in the smallest amount and dissolve/disperse

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5
Q

what is a solvent

A

substances that are in the bigger amount
- mostly water (gases, liquids, solids dissolved in water are solutes)

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6
Q

what needs to happen for a solute to dissolve in a solvent

A

solute-solvent forces of attraction are great enough to overcome forces between solute-solute and solvent-solvent

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7
Q

what happens if all 3 forces are equal in strength

A

substances will be soluble in each other

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8
Q

likes dissolves likes

A
  • charged ions are more attracted to molecules of polar solvents and non-polar molecules are more attracted by non-polar molecules of non-polar solvents
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9
Q

concentration of a solution

A

measure of the amount of solute in a given amount of solution

(mol solute/L solution)
- many also be expressed as millimolar or micro molar

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10
Q

common terms for molarity

A
  • molality: mol solute/kg solvent
  • mole fraction: mol solute/ (mol solute+mol solvent)
  • parts by mass: mass solute/mass solution
  • parts by volume: volume solute/volume solution

= parts by… are expressed as % similar to ppm/ppb (parts per million/billion)

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11
Q

when are ppm/ppb used

A

apply to dilute solutions and report concentration of trace components in water

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12
Q

what is a chemical oscillation

A

cyclic changes occurring within the solution as particular concentrations of solutes rise and diminish in a periodic fashion

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13
Q

molarity for all substances

A
  • 4 solutions total *
    A= 2 solute solution: 0.15 M malonic acid and 0.02 M manganese

B= 2 solute solution of 0.20 M potassium iodate and 0.080 M sulphuric acid

C= a 3.6M hydrogen peroxide solution

D= a 3% (w/v) starch solution

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14
Q

When you mix the solutions…

A
  • you mix the 3 at once and add small drops of the 4th one
  • if the solute concentrations are correct then it should show colour change for ten minutes
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15
Q

how to know if the cyclic nature occurs

A

colour change for 10 mins

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16
Q

what are oscillation reactions

A
  • multi step reactions where intermediates are formed, reacted, reformed, re-reacted, and so on.. in a cyclic fashion
  • cyclic rise and fall of intermediates is observed through colour change
17
Q

who made BR reaction

A

Thomas S. Briggs and Warren C. Raushcer
- gold-yellow to blue to colourless and back again = rise and fall of concentration of iodine containing intermediate and interaction w/ starch

18
Q

HOI

A
  • hypoiodous acid

= thought to depend on its rise and fall (in I2 and I- concentrations)

19
Q

I2 and I- concentration

A

both are high: blue starch-iodide complex

I2 high, I- low: yellow-gold

I2 low, I- high: clear

  • oscillations continue until masonic acid or iodate ions are consumed
20
Q

purpose of H2SO4
purpose of MnSO4
purpose of starch

A

to keep medium, acidic
to provide Mn2+ which is involved in rxn
indicate presence of I2 and I-

= produces redox reactions to help produce I2 and I- intermediates!