Term
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Definition
| No mass or energy transfer |
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Term
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Definition
| No mass transfer but there is energy transfer, due to heat change |
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Term
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Definition
| Both mass and energy transfer |
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Term
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Definition
Measure of the tendency to evaporate
High VP = Volatile = Weak IMF |
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Term
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Definition
| As temperature increases, kinetic energy increases (VP increases) due to increased number of gas molecule that have energy to move to gas phase. |
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Term
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Definition
(s) melt (l) boil/vapour (g)
freeze condense
(s) sublimation (g)
deposition |
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Term
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Definition
| Temperature and pressure at 3 phases of that substance co-exist in thermodynamic equilibrium. |
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Term
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Definition
| Highest temp and pressure point where the material can exist in gas or liquid equilibrium (no difference between g/l). |
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Term
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Definition
| Rapid change from liquid to vapour when VP = atmospheric pressure |
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Term
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Definition
| Temperature at which the VP of the liquid = external pressure. Therfore as height increases, external pressure decreases and BP decreases. |
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Term
| Differences of boiling and evaporation |
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Definition
B: Rapid, specific temp, arises in whole liquid, bubbles
E: Slow, any temp, only occurs on surface, no bubbles |
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Term
| Similarities of boiling and evaporation |
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Definition
| Go from liquid to gas phase |
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Term
| Vapour liquid equilibrium (or phase equilibrium/ rate of evaporation/ condensation) |
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Definition
| liquid phase exits in equilibrium with its vapour at a particular temp (closed systems only) |
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Term
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Definition
BP of solution (mixture) is higher than BP of pure solvent
Explanation: Add NaCl, forms strong ion-dipole attraction with H2O, harder to go to vapour phase, BP increases. Also water (non-volatile) takes up space at interface, less H2O moves to vapour phase |
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Term
| Freezing point depression |
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Definition
Freezing point/MP of a pure solvent is higher than the freezing point/MP of a solution (mixture)
Explanation: When H2O is frozen, forms strong crystal lattice. When NaCl is added, makes it harder for H2O molecules to achieve regular arrangement, harder to freeze. Therefore must lower the temp a lot more than usual to freeze solution. |
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Term
| Fractional Distillation Column |
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Definition
'Separate two volatile components, but must be a volatility difference.'
- A (more volatile component) = vapour/ distillate
- B (less volatile component) = liquid/ waste
- Feed reach T1 (liquid comp), becomes vapour comp also at T1, vapour goes to next tray (100% condenses) and becomes new liquid comp which boils again at T2 (old vapour comp equals to new liquid comp), repeat. |
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Term
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Definition
| The temperature at a given pressure when the first bubble of vapour is formed, starts boiling. Commences the vapourisation of that liquid. |
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Term
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Definition
| The temperature at which the first drop of dew forms from vapour, commencing the condensation of that liquid. |
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Term
| Going up Distillation column |
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Definition
- Temp decreases (away from heat)
- Solution becomes richer of volatile component (A)
- More A in mixture, therefore BP decreases |
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Term
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Definition
| Boils only some of the liquid on each tray as more volatile component evaporates more than less volatile. (new vapour comp does not equal to the old vapour comp) |
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