exp 3 Flashcards
What is VOLALITY?
relative ease by which a substance changed from the liquid to the vapor state
An individual molecule escaping from a liquid requires_____ in order to _____ (2)
energy
- break away from other liquid molecules
- vigorous movement of gaseous particles
What is VAPOR PRESSURE?
it measures the amount of gas particles above the surface of the liquid in a closed vessel
EQUILIBRIUM VAPOR PRESSURE is dependent on….(2)
- the external pressure of the system
- increases with temprature
EVAPORATION
- other term
- definition
- slow volatilization
- escape of surface molecules of liquid into the air
BOILING
- other term
- accompanied by____ due to___
- definition
- rapid volatilization
- accompanied by TURBUBLENCE due to VAPOR FORMATION
- occurs when vapor pressure of liquid is = to external pressure
What is a KNOWN characteristic property of pure liquids
Boiling Point
BOILING POINT occurs at what temperature?
when Pv (vapor pressure) = Pext (external pressure)
The ____ volatile the liquid is, the ____ the boiling point
less
higher
Which has a sharper boiling point: pure liquid or impure liquid?
and why?
PURE LIQUID - a uniform amount of energy is required to disrupt the molecules
Does the boiling point of a substance change/vary?
why or why not?
YES
due to fluctuations in the atmospheric pressure
How can boiling point be determined?
using SIMPLE DISTILLATION
DISTILLATION
- definition
- main function
- commonly used when?
- process of vaporizing a liquid and converting the vapor back to liquid through cooling
- to separate volatile from nonvolatile components in a mixture
- when separating a volatile solvent from a substance that is being purified
PROCESS of SIMPLE DISTILLATION
- Sample is heated
- Vapor passes through a cooling tube
If the sample contains NONVOLATILE IMPURITIES, the vaporize liquid will have a _____ boiling point
and why?
sharp
IMPURITIES will not vaporize so technically PURE LIQUID ang mag eevaporate lng, leaving the impurities behind
BASIC PARTS of DISTILLATION SET-UP (4) for both steam and simple
- distilling flask (round-bottom flask)
- thermometer
- condenser
- receiver
What is fitted to the condenser so that the distillate may be collected in a suitable receiver?
adapter
Can the boiling flask be allowed to stay dry?
NO–even after distillation process, need may unting liquid
What are placed in the distilling flask to prevent BUMPING
Boiling Chips
How much can the distilling flask be filled up?
2/3 of its maximum volume
WHEN does the principle of steam distillation apply? (2)
if the organic substance is:
- insoluble in water
- a BP much higher than 100
ESSENTIAL OILS
- main definition
- insoluble in?
- polarity
- isolated from plant material by______
- a mixture of___?
- most prominent compound found in it are?
- uses what distillation process?
- high-boiling liquids
- insoluble in water
- nonpolar or weak polarity
- steam distillation
- several types of organic compounds
- monoterpenes
- steam distillation
