Glassware

Question 1

Composition of glassware

Answer 1

-mixture of silica from fine sand or pulverized sandstone
-alkali (soda/potash -finer)to lower mp
-stabilizer, lime
-Cullet,assist melting mixture

Question 2

Properties

Answer 2

Varies according to adding of following in oxide form:
Lead
Boron
Barium
Cerium
Metallic acids
Mn

Question 3

Uses of oxides used in glassware

Answer 3

Lead-brilliance &weight
Boron-thermal &electrical resistance
Ba-^ refractive index
Cerium-absorb infracted rays
Metallic oxides-impart color
Mn-decolorising

Question 4

Types of glassware

Answer 4

Hard(borosilicate)-common
Soft (soda lime)

Question 5

Ingredients of hard glassware

Answer 5

(BASS)
Silica-80.6%
Boric oxide-12.6%
Sodium oxide-4.15%
Al oxide-2.2%

Question 6

Properties of hard

Answer 6

Heat resistant
Chemical resistant
Withstand mechanical stress
Preparation of beakers nd glassware for heating
Expensive

Question 7

Features of soft /sodalime glasswares

Answer 7

-high alkali composition
-free soda present in sodalime, neutralised before use
Less resistant to thermal &mechanical shock
-cheaper than hard
-ideal for storage of reagents
-easy to bend and break
-used to make Pasteur pipette and other glassware
-low cost
-easily available
-poor resistant to heat

Question 8

Varieties of glassware

Answer 8

Corex -6 times stronger than hard
Alkali resistant -thermal resistance
Lead oxide
Ground
Bottle
Low actinic
Fused silica
Alumino silicate

Question 9

Grades of glassware

Answer 9

Hard glass
Borosilicate glass
Heat resistant Borosilicate -widely used,pyrex glass
Low alkali Borosilicate
Class A-high accuracy
Class B-when accuracy is not critical
Specially treated -acid washed
Specially washed -coated with silicon, Teflon,other coatings inside

Question 10

Composition of aluminosilicate

Answer 10

Silica-57%
Alumina-16%
Boric acid-4%
Barium oxide-6%
Mg-7%
Lime-10%

Question 11

Composition of lead oxide

Answer 11

Silica-59%
Soda (na2o)-2%
Lead oxide-25%
K2o-12%
Alumina-0.4%
Zinc oxide-1.5%