Study Set Content:
- Temperature at which solid melts
- Melting of pure substance is
foxed while impure substance
melts over a wide range of
temp
Melting point
- Occurs when the vapor pressure of a substance is greater than the atmospheric pressure
- Use in purification of substances that have non-volatile impurities or those that have lower vapor pressure than pure compound
Sublimation
BENZOIC ACID formula
(C6H5COOH)
- Simplest aromatic carboxylic acid
- White Crystalline powder
Benzoic acid
Benzoic acid mp and bp
- MP: 122 C
- BP: 249 C
- Uses: food preservative, germicide, or
antifungal agent. Use in production of
cosmetics, dyes, plastic and insect repellants
Benzoic acid
Temparature at which the substance started to melt
119
Temparature at which the benzoic acid started to melt
119
Temparature at which the substance melted completely
122
Temparature at which benzoic acid melted completely
123
is a solvent that shows the desired solubility
behavior for the substance to be crystallized.
recrystallizing solvent
The compound should be (blank) at room temp
insoluble
upon heating
very soluble
upon cooling
insoluble
It occurs when the solid substance melts and forms a liquid
that is insoluble in the solvent. When cooling the liquid becomes super
cooled liquid or oils. Oils may solidify if the temperature is lowered, yet
it will not crystallize.
Oiling out
Recrystallizing Solvent should be:
• Volatile enough to be easily removed from the solution after
crystallization.
• Chemical Reactivity should be low
• Neither decompose nor oxidize the desired substance.
• Should not react to the compound to be purified.
- A process used to eliminate unwanted substances or parts from the experimental samples or solutions
Filtration
- Are decolorizing agents use to remove colored impurities.
Activated Charcoal
Room Temp.
Water
Room Temp. Water
negative
