
- •11.1 Cooling
- •Table 11.2 Molecular Lowering of the Melting or Freezing Point
- •11.2 Drying and Humidification
- •11.3 Boiling Points and Heating Baths
- •Table 11.8 Organic Solvents Arranged by Boiling Points
- •Table 11.9 Molecular Elevation of the Boiling Point
- •11.4 Separation Methods
- •Table 11.11 Solvents of Chromatographic Interest
- •11.4.1 McReynolds’ Constants
- •11.4.2 Chromatographic Behavior of Solutes
- •11.4.3 Ion-Exchange (Normal Pressure, Columnar)
- •Table 11.16 Guide to Ion-Exchange Resins
- •Table 11.18 Relative Selectivity of Various Counter Anions
- •11.5 Gravimetric Analysis
- •Table 11.19 Gravimetric Factors
- •Table 11.20 Elements Precipitated by General Analytical Reagents
- •Table 11.21 Cleaning Solutions for Fritted Glassware
- •Table 11.25 Tolerances for Analytical Weights
- •Table 11.26 Heating Temperatures, Composition of Weighing Forms, and Gravimetric Factors
- •11.6 Volumetric Analysis
- •Table 11.28 Titrimetric (Volumetric) Factors
- •11.6.3 Standard Volumetric (Titrimetric) Redox Solutions
- •11.6.4 Indicators for Redox Titrations
- •11.6.5 Precipitation Titrations
- •11.6.6 Complexometric Titrations
- •11.6.7 Masking Agents
- •11.6.8 Demasking
- •Table 11.30 Standard Solutions for Precipitation Titrations
- •Table 11.31 Indicators for Precipitation Titrations
- •Table 11.32 Properties and Applications of Selected Metal Ion Indicators
- •Table 11.41 Pipet Capacity Tolerances
- •Table 11.43 Buret Accuracy Tolerances
- •11.7 Laboratory Solutions
- •11.7.1 General Reagents, Indicators, and Special Solutions
- •Table 11.49 TLV Concentration Limits for Gases and Vapors
- •Table 11.52 Chemicals Which Polymerize or Decompose on Extended Refrigeration
- •11.9 Thermometry
- •11.9.1 Temperature and Its Measurement
- •11.10 Thermocouples
- •Table 11.63 Type T Thermocouples: Copper vs. Copper-Nickel Alloy
- •11.11 Correction for Emergent Stem of Thermometers

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PRACTICAL LABORATORY INFORMATION |
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11.103 |
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TABLE 11.41 Pipet Capacity Tolerances |
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Volumetric transfer pipets |
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Measuring and serological pipets |
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Tolerances,* |
mL |
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Tolerances,† mL |
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Class A |
Class B |
Capacity, mL |
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Capacity, mL |
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Class B |
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0.5 |
0.006 |
0.012 |
0.1 |
0.005 |
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1 |
0.006 |
0.012 |
0.2 |
0.008 |
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2 |
0.006 |
0.012 |
0.25 |
0.008 |
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3 |
0.01 |
0.02 |
0.5 |
0.01 |
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4 |
0.01 |
0.02 |
0.6 |
0.01 |
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5 |
0.01 |
0.02 |
1 |
0.02 |
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10 |
0.02 |
0.04 |
2 |
0.02 |
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15 |
0.03 |
0.06 |
5 |
0.04 |
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20 |
0.03 |
0.06 |
10 |
0.06 |
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25 |
0.03 |
0.06 |
25 |
0.10 |
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50 |
0.05 |
0.10 |
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100 |
0.08 |
0.16 |
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* Accuracy tolerances for volumetric transfer pipets are given by ASTM standard E969 and Federal Specification NNN-P- 395.
† Accuracy tolerances for measuring pipets are given by Federal Specification NNN-P-350 and for serological pipets by Federal Specification NNN-P-375.
TABLE 11.42 |
Tolerances of Micropipets (Eppendorf) |
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Capacity, L |
Accuracy, % |
Precision, % |
Capacity, |
L |
Accuracy, % |
Precision, % |
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10 |
1.2 |
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0.4 |
100 |
0.5 |
0.2 |
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40 |
0.6 |
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0.2 |
250 |
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0.5 |
0.15 |
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50 |
0.5 |
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0.2 |
500 |
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0.5 |
0.15 |
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60 |
0.5 |
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0.2 |
600 |
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0.5 |
0.15 |
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70 |
0.5 |
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0.2 |
900 |
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0.5 |
0.15 |
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80 |
0.5 |
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0.2 |
1000 |
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0.5 |
0.15 |
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TABLE 11.43 Buret Accuracy Tolerances
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Accuracy, |
mL |
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Class A* and |
Class B and |
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Capacity, mL |
Subdivision, mL |
precision grade |
standard grade |
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10 |
0.05 |
0.02 |
0.04 |
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25 |
0.10 |
0.03 |
0.06 |
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50 |
0.10 |
0.05 |
0.10 |
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100 |
0.20 |
0.10 |
0.20 |
* Class A conforms to specifications in ASTM E694 for standard taper stopcocks and to ASTM E287 for Teflon or polytetrafluoroethylene stopcock plugs. The 10-mL size meets the requirements for ASTM D664.
11.104 |
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SECTION 11 |
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TABLE 11.44 |
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Factors for Simplified Computation of Volume |
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The volume is determined by weighing the water, having a temperature of |
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t C, contained or delivered by the |
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apparatus at the same temperature. The weight of water, |
w grams, is obtained with brass weights in air having |
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a density of 1.20 mg/mL. |
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For apparatus made of soft glass, the volume contained or delivered at 20 |
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C is given by |
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20 w |
ƒ20 mL |
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where |
20 is the volume at 20 |
and ƒ |
20 is the factor (apparent specific volume) obtained from the table below for |
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the temperature |
t |
at which the |
calibration is performed. The volume at any other temperature |
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t may |
then be |
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obtained from |
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20[1 0.00002(t 20)] mL |
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For apparatus made of any other material, the volume contained or delivered at the temperature |
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t |
is |
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t wf |
t mL |
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where |
w is again the weight in air obtained with brass weights (in grams), and |
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ft is the factor given in the third |
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column of the table for the temperature |
t. The volume at any temperature |
t may then be obtained from |
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t t[1 (t t)] mL |
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where is the cubical coefficient of thermal expansion of the material from which the apparatus is made. |
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Approximate values of |
for some frequently encountered materials are given in Table 11.45. |
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t, C |
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ƒ 20 |
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ƒt |
t, C |
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ƒ 20 |
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ƒt |
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0 |
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1.001 62 |
1.001 22 |
20 |
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1.002 86 |
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1.002 86 |
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1 |
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54 |
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16 |
21 |
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1.003 05 |
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1.003 07 |
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2 |
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48 |
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12 |
22 |
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26 |
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30 |
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3 |
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43 |
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09 |
23 |
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47 |
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53 |
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4 |
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41 |
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09 |
24 |
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69 |
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77 |
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5 |
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1.001 39 |
1.001 09 |
25 |
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1.003 93 |
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1.004 0 |
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6 |
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40 |
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12 |
26 |
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1.004 17 |
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29 |
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7 |
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42 |
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16 |
27 |
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42 |
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56 |
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8 |
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45 |
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21 |
28 |
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68 |
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84 |
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9 |
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50 |
28 |
29 |
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95 |
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1.005 13 |
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10 |
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1.001 56 |
1.001 36 |
30 |
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1.005 23 |
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1.005 43 |
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11 |
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63 |
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45 |
31 |
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1.005 52 |
1.005 74 |
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12 |
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72 |
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56 |
32 |
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1.005 82 |
1.006 06 |
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13 |
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82 |
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68 |
33 |
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1.006 13 |
1.006 39 |
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14 |
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93 |
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81 |
34 |
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1.006 44 |
1.006 72 |
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15 |
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1.002 06 |
1.001 96 |
35 |
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1.006 77 |
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1.007 0 |
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16 |
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20 |
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1.002 12 |
36 |
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1.007 10 |
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1.007 42 |
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17 |
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35 |
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29 |
37 |
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1.007 44 |
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1.007 78 |
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18 |
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51 |
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47 |
38 |
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1.007 79 |
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1.008 15 |
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19 |
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68 |
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66 |
39 |
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1.008 15 |
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1.008 53 |
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40 |
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1.008 52 |
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1.008 91 |
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PRACTICAL |
LABORATORY INFORMATION |
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11.105 |
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TABLE 11.45 |
Cubical Coefficients of Thermal Expansion |
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This table lists values of , the cubical coefficient of thermal expansion, taken from “Essentials of Quantitative |
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Analysis,” by Benedetti-Pichler, and from various other sources. The value of |
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represents the relative increases |
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in volume for a change in temperature of 1 |
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C at temperatures in the vicinity of 25 |
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C, and is equal to 3 |
, where |
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is the linear coefficient of thermal expansion. Data are given for the types of glass from which volumetic |
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apparatus is most commonly made, and also for some other materials which have been or may be used in the |
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fabrication of apparatus employed in analytical work. |
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Material |
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Glasses |
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Alkali-resistant, Corning 728 |
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1.90 |
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5 |
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10 |
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Gerateglas, Schott G20 |
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1.47 |
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Kimble KG-33 (borosilicate) |
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0.96 |
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N-51A (“Resistant”) |
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1.47 |
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R-6 (soft) |
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2.79 |
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Pyrex, Corning 744 |
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0.96 |
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Vitreous silica |
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0.15 |
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Vycor, Corning 790 |
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0.24 |
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Metals |
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Brass |
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ca. |
5.5 |
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Copper |
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5.0 |
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Gold |
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4.3 |
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Monel metal |
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4.0 |
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Platinum |
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2.7 |
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Silver |
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5.7 |
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Stainless steel |
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ca. |
5.3 |
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Tantalum |
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ca. |
2.0 |
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Tungsten |
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1.3 |
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Plastics and other materials |
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Hard rubber |
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24 |
5 |
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10 |
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Polyethylene |
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45– 90 |
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Polystyrene |
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18– 24 |
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Porcelain |
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ca. |
1.2 |
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Teflon (polytetrafluoroethylene) |
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16.5 |
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TABLE 11.46 |
General Solubility Rules for Inorganic Compounds |
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Nitrates |
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All nitrates are soluble. |
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Acetates |
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All acetates are soluble; silver acetate is moderately soluble. |
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Chlorides |
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All chlorides are soluble except AgCl, PbCl |
2 , and Hg |
2 Cl 2 . PbCl 2 is soluble in |
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hot water, slightly soluble in cold water. |
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Sulfates |
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All sulfates are soluble except barium and lead. Silver, mercury(I), and cal- |
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cium are only slightly soluble. |
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Hydrogen sulfates |
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The hydrogen sulfates are more soluble than the sulfates. |
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Carbonates, phosphates, |
All carbonates, phosphates, chromates, and silicates are insoluble, except those |
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chromates, silicates |
of sodium, potassium, and ammonium. An exception is MgCrO |
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4 |
which is |
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soluble. |
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Hydroxides |
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All hydroxides (except lithium, sodium, potassium, cesium, rubidium, and am- |
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monia) are insoluble; Ba(OH) |
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2 is moderately soluble; Ca(OH) |
2 and Sr(OH) |
2 |
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are slightly soluble. |
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Sulfides |
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All sulfides (except alkali metals, ammonium, magnesium, calcium, and bar- |
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ium) are insoluble. Aluminum and chromium sulfides are hydrolyzed and |
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precipitate as hydroxides. |
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Sodium, potassium, |
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All sodium, potassium, and ammonium salts are soluble. Exceptions: |
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ammonium |
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Na |
4 Sb2 O |
7 , K2 NaCo(NO |
2 )6 , K2 PtCl 6 , (NH 4 ) 2 PtCl |
6 |
, and (NH |
4 )2 NaCo(NO |
2 )6 . |
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Silver |
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All silver salts are insoluble. Exceptions: AgNO |
3 |
and AgClO |
4 ; AgC |
2 H 3 O 2 |
and |
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Ag |
2 SO |
4 |
are moderately soluble. |
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