CHEM LECTURE

Question 1

IS THE MOST PRACTICAL METHOD OF PURIFICATION

Answer 1

recrystalization

Question 2

the substance is dissolved in a solvent and again put in crystalline form under conditions which insure greater impurity

Answer 2

crystallization

Question 3

is employed to remove a solute from a solvent usually water, when distillation is undesirable.

Answer 3

extraction

Question 4

what apparatus is being used during extraction?

Answer 4

separatory funnel

Question 5

a substance where it passes directly from solid to the gaseous state when heater and again from vapor to solid upon cooling

Answer 5

sublimation

Question 6

how many grams of impure acetanilide was used in the experiment?

Answer 6

5 grams

Question 7

what reagent was used for the droppings?

Answer 7

congo red

Question 8

whats the chemical formula of acetanilide?

Answer 8

C6H5NHCOCH3

Question 9

how many grams of animal charcoal were added?

Answer 9

1 gram

Question 10

what should be the color of the filtrate when it was filtered?

Answer 10

colorless

Question 11

whats the formula for the computation of the %yield of a product?

Answer 11

%yield= actual yield/theortical yeld x 100%

Question 12

whats the chemical formula for the benzoic acid?

Answer 12

C6H5COOH

Question 13

how many grams of benzoic acid were placed in the beaker?

Answer 13

1g

Question 14

what was added to the mixture of benzoic acid and sodium chloride?

Answer 14

chloroform

Question 15

where does the chloroform layer lie on the water level?

Answer 15

lies below the water because it has a higher density than the water

Question 16

whats the equation of the test for chlorides?

Answer 16

AgNO3 — HNO3—> NaNO3+AgCl

Question 17

Chemical name for AgNO3

Answer 17

Silver nitrate

Question 18

HNO3

Answer 18

Nitric Acid

Question 19

NaNO3

Answer 19

Sodium nitrate

Question 20

AgCl

Answer 20

Silver Chloride

Question 21

what was the color of the precipitate in the experiment?

Answer 21

White

Question 22

it is an acid-base indicator?

Answer 22

Congo red

Question 23

is employed to remove a solute from a solvent

Answer 23

Extraction

Question 24

on standing the liquids separate into two layers which are removed from a __________

Answer 24

Separatory Funnel

Question 25

a substance passes directly from solid to the gaseous state?

Answer 25

Sublimation

Question 26

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

Answer 26

Sublimation