|
Pyrex Borosilicate
|
GE Quartz
|
|
Annealing Point
|
560oC
|
1215oC
|
|
Strain Point
|
510oC |
1120oC |
|
Softening Point
|
821oC |
1683oC |
|
Refractive Index
|
1.437 |
1.4585 |
|
Coefficient of Expansion x 10-7
|
32.5 |
5.5 |
|
Density
|
2.23 |
2.2 |
|
Temperature Limits
|
490oC (extreme)
230oC (normal) |
|
|
Maximum Thermal Shock
|
160oC
|
|
|
TEMPERATURE CONVERSIONS
oC= (oF - 32) 5/9
oF= (oC + 32) 9/5
|
OHMs LAW
I = E/R
E = IR
R = E/I
P = IE |
I = amps
E = volts
R = ohms
P = watts |
|
|
Example: If 120 volts applied to circuit, then I - 120/115 = 1.04
amps
(volts)(amps) = watts
(120)(1.04) = 125
I2(R) = P
1.042(115) = 125
|
|
|
Borosilicate glass is a strong heat-resistant glass that contains a minimum of 5 percent boric oxide.
|
Fritted Glassware
New filters should be cleaned by suction with hot hydrochloric acid followed by
a water rinse. Used filters can be cleaned by rinsing with water,
passed through the underside of the filter disc at pressure not exceeding
15lbs. per square inch. There are some precipitates that tend to clog the
pores of a fritted filter.
Listed below are suggested cleaning precipitates that must be removed by
chemical means.
|
|
|
|
MATERIAL
|
CLEANING AGENT
|
|
Albumen
|
hot ammonia or hydrochloric acid
|
|
Aluminous and Siliceous Residues
|
2% hydrofluoric acid followed by concentrated sulfuric acid. Rinse
immediately with water until no trace of acid can be detected.
|
|
Copper or Iron Oxides
|
hot hydrochloric acid plus potassium chlorate
|
|
Glucose
|
hot mixed acid (H2SO4 + HNO3)
|
|
Fatty Materials
|
carbon tetrachloride
|
|
Mercuric Sulfide
|
hot nitric acid
|
|
Mercury
|
hot concentrated cleaning solution, or hot concentrated sulfuric
acid with a few drops of sodium nitrate.
|
|
Organic Matter
|
|
|
Silver Chloride
|
ammonium hyposulfide
|