Page 29 - Demo

“Your Safer Source for Science”
sec-BUTYL ALCOHOL continued
 HAZARD ALERT: May form explosive peroxides on concentra- tion. If you don’t know the age of this material, do not use it. All Flinn chemicals are date labeled. Flammable, fire risk; eye irritant; absorbed by skin. LD50 2193 mg/kg. TLV 303 mg/m3.
Storage: Organic #2 in a dedicated flammables cabinet; if one is not available store in a Flinn Saf-Stor TM Can.
Disposal: #18b
Shelf Life: Poor. Substance has been known to develop explosive peroxides. Buy only as little as possible and avoid prolonged storage.
Soluble: Miscible with alcohol and ether; slightly soluble with water.
Color and Odor: Colorless liquid with rubbing alcohol-like odor. CAS No. 78-92-2
Save On HazMat Fees
27
tert-Butyl Alcohol
2-methyl-2-propanol laboratory grade (CH3)3COH
F.W. 74.12
B0179 B0055
100 mL $ 8.05 500 mL 14.25/1 82.92/6
Continued on next column.
n-Butyl Bromide
see 1-Bromobutane
sec-Butyl Bromide
see 2-Bromobutane
1-Butyl Chloride
see 1-Chlorobutane
tert-Butyl Chloride
2-chloro-2-methylpropane (CH3)3CCl
F.W. 92.57
tert-BUTYL ALCOHOL continued
 HAZARD ALERT: Moderate fire risk; slightly toxic by ingestion and inhalation; eye irritant; absorbed by skin. LD50 2743 mg/kg. TLV 303 mg/m3.
Storage: Organic #2 in a dedicated flammables cabinet; if one is not available store in a Flinn Saf-Stor TM Can.
Disposal: #26b
Shelf Life: Fair
Soluble: Miscible with alcohol and ether; soluble in water.
Color and Odor: Colorless liquid with camphor odor.
CAS No. 75-65-0
Technical Note: Melting point is 25 °C; this substance may be a solid at room temperature.
 HAZARD ALERT: Flammable liquid, slightly toxic by ingestion, inhalation, and skin absorption.
Storage: Organic #4
Disposal: #27j
Shelf Life: Indefinite
Soluble: Alcohol; slightly in water.
Color and Odor: Colorless liquid with ethyl ether odor. CAS No. 507-20-0
Butyl Stearate
butyl octadecanoate laboratory grade
C22H44O2 F.W. 340.57
 HAZARD ALERT: Combustible solid. Storage: Organic #3
Disposal: #18b
Shelf Life: Good; indefinite.
B0183 500 g
$34.75
B0236 25 mL
$25.05
Understand Buffer Solutions
and pH
What is pH?
The pH scale represents the acidity or alkalinity of an aqueous solution. pH is defined as the negative logarithm of the hydrogen ion concentra- tion of a solution. pH = –log[H+].
Absolutely pure water is the standard used in determining pH value. Since pH measurements depend on the chemical properties of water, the pH scale is not accurate for nonaqueous solutions. The pH scale was established with a range of 0 to 14 pH units. The low end of the scale is acid, the high end alkaline, with pH 7.00 at the mid-point as neutral.
Each unit on the pH scale represents a tenfold difference in acidity level. For example, pH 4 is ten times as acidic as pH 5. A pH 3 solution has ten times the acidity level of a pH 4 solution and 100 times the acid- ity level of a pH 5 solution.
What is a buffer?
A buffer is a chemical substance that resists changes in pH upon the addition of excess strong acid or strong base.
A buffer solution contains both a weak acid and its conjugate weak base. The weak acid component neutralizes any excess strong base added to the solution while the weak base component neutralizes any excess strong acid that may be added. As a result, a buffer solution maintains a constant hydrogen ion concentration despite the addition of relatively large quantities of acid or base.
Faculty should know that water (distilled or deionized) has no “buffer effect.” In fact, the use of “dip and read” test papers will quickly influ- ence the pH of the pure water. Almost always, the test paper used in such water will read pH 5.00 after the paper has been dipped in the water even though the actual pH of the water may be entirely different. In this example, the test paper itself has had an effect on the pH value of the water. Good quality water is not a substitute for a buffer.
What are pH test papers?
pH papers are made with special indicator dyes that react (change color) at specific pH values. Two pH units is the useful limit for most indicators and indicator papers. No further perceptible color change will occur regardless of a further pH change in the solution being tested. For example, using test paper with a pH range of 6.00 to 8.00, a reading can be successfully taken if the pH falls between the aforementioned points. If the pH is actually below 6.00 or higher than 8.00, the test paper cannot detect that change and will simply change color to one extreme or the other of its 2.00 pH unit range.
pH papers may not be reliable in aqueous solutions containing proteins or alkaloids (e.g., nitrogen-based substances of plant origin like nicotine).
Soluble: Alcohol and ether; not water.
Color and Odor: Colorless solid with faint, fatty odor.
CAS No. 123-95-5
Technical Note: Melting point is 27 °C; may be a liquid or fused solid.
Butyric Acid
butanoic acid laboratory grade CH3CH2CH2COOH F.W. 88.11
B0180
B0139
B0035
25 mL 100 mL 500 mL
$13.15 20.20 43.25
(All above package sizes packaged
in PVC-coated bottles)
BUTYRIC ACID continued on next page.
Chemical Odors
Many chemicals, particularly organic chemicals, have a char- acteristic odor. Odor information has been added to each of our chemical listings. Practical and brief odor identification terms have been used to keep it simple. Chemical odor and chemical color are unique pieces of information provided only by Flinn Scientific.