CHEM LECTURE Flashcards
IS THE MOST PRACTICAL METHOD OF PURIFICATION
recrystalization
the substance is dissolved in a solvent and again put in crystalline form under conditions which insure greater impurity
crystallization
is employed to remove a solute from a solvent usually water, when distillation is undesirable.
extraction
what apparatus is being used during extraction?
separatory funnel
a substance where it passes directly from solid to the gaseous state when heater and again from vapor to solid upon cooling
sublimation
how many grams of impure acetanilide was used in the experiment?
5 grams
what reagent was used for the droppings?
congo red
whats the chemical formula of acetanilide?
C6H5NHCOCH3
how many grams of animal charcoal were added?
1 gram
what should be the color of the filtrate when it was filtered?
colorless
whats the formula for the computation of the %yield of a product?
%yield= actual yield/theortical yeld x 100%
whats the chemical formula for the benzoic acid?
C6H5COOH
how many grams of benzoic acid were placed in the beaker?
1g
what was added to the mixture of benzoic acid and sodium chloride?
chloroform
where does the chloroform layer lie on the water level?
lies below the water because it has a higher density than the water
whats the equation of the test for chlorides?
AgNO3 — HNO3—> NaNO3+AgCl
Chemical name for AgNO3
Silver nitrate
HNO3
Nitric Acid
NaNO3
Sodium nitrate
AgCl
Silver Chloride
what was the color of the precipitate in the experiment?
White
it is an acid-base indicator?
Congo red
is employed to remove a solute from a solvent
Extraction
on standing the liquids separate into two layers which are removed from a __________
Separatory Funnel
a substance passes directly from solid to the gaseous state?
Sublimation
the operation is slow but the product is usually very pure, so where a small amount of material is to be purified, this method may be preferred in those cases where it can be used
Sublimation
