EXP 8 AND 9

Question 1

is defined as the state in which any residue of the unit except for the fragments of the insoluble coating or capsule shell remaining on the screen of the test apparatus is a soft mass having no palpably firm core

Answer 1

Disintegration

Question 2

are substances or agents added to compressed tablets to cause them to break apart or disintegrate when placed in aqueous medium

Answer 2

Disintegrants

Question 3

Experiment 8 objective

Answer 3

To determine the rate of disintegration of uncoated tablets

Question 4

Reagents/chemicals needed for Exp. 8:

Answer 4

6 ascorbic acid tablets

Question 5

Equipment/Materials used for Exp. 8:

Answer 5

Disintegration apparatus

Question 6

Procedures for Exp.8

Answer 6

1. Place one tablet in each of the six test tubes of the basket and operate the
   disintegration apparatus, using distilled water maintained at 37ºC as the
   immersion fluid.
2. Set the disintegration apparatus timer every five (5) minutes for 6 times or until
   the tablets begin to break.
3. At the end, lift the basket from the fluid. Observe.
   USP Requirement: Ascorbic acid tablets should disintegrate within 30 minutes.

Question 7

USP Requirement for Exp. 8

Answer 7

Ascorbic acid tablets should disintegrate within 30 minutes.

Question 8

The first step for Exp. 8

Answer 8

Place one tablet in each of the six test tubes of the basket and operate the
disintegration apparatus, using distilled water maintained at 37ºC as the
immersion fluid.

Question 9

The 2nd step for Exp. 8

Answer 9

Set the disintegration apparatus timer every five (5) minutes for 6 times or until
the tablets begin to break.

Question 10

The 3rd step for Exp. 8

Answer 10

At the end, lift the basket from the fluid. Observe.

Question 11

What type of water is used in Exp. 8 and the temperature maintained

Answer 11

Distilled water at 37 degrees Celsius

Question 12

Every how many minutes was the Disintegration apparatus set to be checked and for how many times?

Answer 12

5 minutes; 6 times or until the tablets begin to break.

Question 13

When phases exist together, the boundary between the two of them is termed an____

Answer 13

interface

Question 14

The properties of the molecules forming the interface are often sufficiently different from those in the bulk of each phase that they are referred to as forming an
_____

Answer 14

interfacial phase

Question 15

If a _____ and its _____ exist together in the same container, the liquid
takes the bottom part of the container.

Answer 15

liquid; vapor

Question 16

The remainder of the container is filled up by the______, which, as with any gas, has the tendency to take up all available space.

Answer 16

liquid-vapor

Question 17

Molecules in both the liquid and the Gas are in ______ and can move from the liquid into the vapor and back, from the vapor to the liquid.

Answer 17

constant motion

Question 18

However, the distinct boundary
between the vapor and the liquid is preserved under ______ and the
______ does not destroy the equilibrium between these two phases due to
the ____ character of this boundary.

Answer 18

constant temperature; exchange of molecules; labile

Question 19

Objectives of Exp. 9

Answer 19

1. To determine and apply the different methods of measuring the surface tension of
   liquids.
2. To observe and explain the different interfacial properties of surfactant.

Question 20

Reagents/Chemicals used for Exp. 9

Answer 20

Liquid detergent
Water
Sulfur powder
Alcohol
Talc
Mineral oil
Tween 80

Question 21

Equipments/ Materials used for Exp. 9

Answer 21

Equal-arm analytical balance
Ruler
Pipette
Aspirator
Glass capillary tube
Beaker
Dropper

Question 22

Procedure for Capillary method

Answer 22

1. Measure the diameter of the capillary tube.
2. Fill the beaker with water and dip the capillary tube just below the surface of the
   liquid.
3. Note the rise of liquid in the capillary tube. Measure the height of rise from the
   surface of the liquid to the lower meniscus.
4. Record the data and compute the surface tension using the equation:
   Surface tension (γ) = ½ rhρg
5. Repeat the same procedure with alcohol and mineral oil.

Question 23

Formula for surface tension

Answer 23

(γ) = ½ rhρg

Question 24

Surface tension (γ) = ½ rhρg

Where r =

Answer 24

radius of the capillary tube

Question 25

Surface tension (γ) = ½ rhρg

Where h=

Answer 25

height of rise of liquid

Question 26

Surface tension (γ) = ½ rhρg

Where p=

Answer 26

density of the liquid

Question 27

Surface tension (γ) = ½ rhρg

Where g=

Answer 27

acceleration of gravity (981 cm/sec2)

Question 28

INTERFACIAL PROPERTIES OF SURFACTANT

Procedure A

Answer 28

1. Prepare four (4) concentrations of detergent solution as follows: 0.25%, 0.5%,
   0.74% and 1.0%.
2. Make 2 marks on the pipette, approximately 1 mL in volume. Fill the pipette
   with water up to the upper mark.
3. Allow the liquid to drain slowly up to the lower mark counting the drops.
4. Record the number of drops and repeat one more time.
5. Repeat the same procedure with detergent solutions prepared previously
   Note: The greater the number of drops, the lower the surface tension.

Question 29

INTERFACIAL PROPERTIES OF SURFACTANT

Procedure B

Answer 29

1. Prepare 2 beakers filled with water. Sprinkle sulfur powder into it. Observe.
2. In beaker 1, add 1 to 2 drops of detergent solution, and in beaker 2, add 1 to 2
   drops of Tween 80. Observe.
3. Repeat the same procedure using talc powder instead of sulfur.