chemistry laboratory (by : rezaee. shalbafan . mozaffari)
Sunday, March 28, 2010
Benedict's Solution test, MSDS
Benedict's reagent:
(also called Benedict's solution or Benedict's test) is a chemical reagent named after an American chemist, Stanley Rossiter Benedict.[1]
Benedict's reagent is used as a test for the presence of reducing sugars. This includes all monosaccharides and the disaccharides , lactose and maltose. Even more generally, Benedict's test will detect the presence of aldehydes (except aromatic ones), and alpha-hydroxy-ketones, including those that occur in certain ketoses. Thus, although the ketose fructose is not strictly a reducing sugar, it is an alpha-hydroxy-ketone, and gives a positive test because it is converted to the aldoses glucose and mannose by the base in the reagent.[2].
One litre of Benedict's reagent can be prepared from 100 g of anhydrous sodium carbonate, 173 g of sodium citrate and 17.3 g of copper(II) sulfate pentahydrate.[3] It is often used in place of Fehling's solution.
Benedict's reagent contains blue copper(II) ions (Cu2+) which are reduced to copper(I) (Cu+). These are precipitated as red copper(I) oxide which is insoluble in water.
Procedure
To a solution or suspension of 0.2 g of unknown in 5 mL of water, add 5 mL of Benedict's solution. If no precipitate is formed, heat the mixture to boiling and cool.
Benedict's solution:
A solution of 17.3 g of sodium citrate and 10.0 g of anhydrous sodium carbonate in 80.0 mL of water is heated until the salts are dissolved. Additional water is added to bring the volume up to 85.0 mL. A solution of 1.73 g of hydrated copper sulfate in 10.0 mL of water is poured slowly with stirring into the solution of the citrate and the carbonate. Add water to make a final volume of 100 mL.
Positive Test
Precipitation of copper(I) oxide as a red, yellow, or yellowish-green solid is a positive test.
Complications
Not general for simple aldehydes and ketones.
Hydrazine derivatives give a positive test.
MSDS FOR Copper Sulfate:
Common Name Copper Sulfate
Manufacturer Old Bridge Chemicals, Inc.
P.O. Box 194
Old Bridge, New Jersey 08857
Telephone (732) 727-2225
Emergency Telephone 1(800) 275-3924
This document is prepared pursuant to the OSHA Hazard Communication Standard (29 CFR 1910.1200).
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SECTION I. MATERIAL IDENTIFICATION
Common Name Copper Sulfate
Synonyms Blue Vitrol, Bluestone, Cupric Sulfate
Molecular Formula CuSO4 • 5H20
EPA Reg. Number 46923-4
CAS Number 7758-99-8
SIC Number 28199 C 29
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SECTION II. PHYSICAL DATA
Physical State Blue crystals or powder
Boiling Point -5 H2O @ 150 C
Melting Point -4 H2O @ 110 C
Specific Gravity 2.284
Solubility in H2O 22.37% @ 0 C
117.95% @ 100 C
Solubility in other solvents Soluble in methanol, glycerol and slightly soluble in ethanol
Appearance Blue crystals or powder
Odor Odorless
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SECTION III. FIRE AND EXPLOSION DATA
Flash Point Not applicable
Flammable Limits Not flammable. If heated above 400 C it can decompose to emit toxic fumes of oxide and sulfur.
Extinguishing Media Copper Sulfate does not burn nor will it support combustion. If stored with other combustible products use water, CO2 or dry chemical.
Special Fire Fighting Instructions If dry heated above 600 C, SO2 is evolved. If water is used it will solubalize the Copper Sulfate and care should be taken to keep such water out of streams or other water bodies.
Fire and Explosion Hazards None
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SECTION IV. REACTIVITY DATA
Stability Stable
Conditions to Avoid Product is highly soluble, but does not react with water.
Incompatibility None know when product remains dry. Product readily dissolves in water. Solutions are mildly corrosive to steel. Store solutions in plastic or rubber or 304, 347 or 316 stainless steel. Iron and moisture should be avoided. Store in a dry area. With exposure to air it will oxidize and turn whitish.
Hazardous Decomposition Products None at normal production temperatures and pressures. If dry heated above 600 C toxic sulfur may evolve.
Polymerization Will not occur.
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SECTION V. HEALTH AND HAZARD INFORMATION
Swallowing Toxic orally in accordance with FHSLA regulations. Acute oral LD50 (male rats) = 472 mg/kg.
Skin Non-toxic. Skin irritation index is zero in accordance with FHSLA regulations.
Eyes Corrosive in accordance with FHSLA regulations. Eye irritation score: 24 hours = 41.67; 48 hours = corrosive
Inhalation Inhalation of dust may cause irritation to the upper respiration tract.
Carcinogenicity None as per NTP, OSHA, and IARC.
This product contains Copper Sulfate subject to the reporting requirements of Section 13 of the Emergency Planning and Community-right-to-Know-Act of 1986 (40 CFR 372).
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SECTION VI. FIRST AID PROCEDURES
Swallowing Give large amounts of milk or water. Induce vomiting. Call Poison Control Center or a physician.
Skin Wash thoroughly with soap and water. Remove and wash contaminated clothing before reuse.
Eyes Immediately flush eyes with plenty of water for 15 minutes. Hold eyelids apart during irrigation. Call a physician.
Inhalation Remove person to fresh air and call a physician.
Carcinogenicity None
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SECTION VII. HANDLING PRECAUTIONS
Personal Protective Equipment Chemical safety goggles. Rubber gloves and rubber apron may be worn.
Ventilation TWA = 1 mg/l for Copper Sulfate. When TWA exceeds this limit in the workplace, provide appropriate ventilation. Wear an approved respirator for dusts or mists: MSHA/NIOSH approved number prefix TC-21C, or a NIOSH approved respirator with any R, P or HE filter.
Alternatively, provide respiratory protection equipment in accordance with Paragraph 1910.134 of Title 29 of the Code of Federal Regulations.
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SECTION VIII. ENVIRONMENTAL AND DISPOSAL INFORMATION
Aquatic Toxicity LC50, 24 hours, Daphnia magna equals 0.182 mg/l. Rainbow Trout equals 0.17 mg/l. Blue Gill equals 1.5 mg/l. All values are expressed as Copper Sulfate Pentahydrate. Test water was soft.
Spills and Leaks Comply with Federal, State and local regulations on reporting spills. Do not wash away crystals or powder. Recover dry if possible. If product is in a confined solution, react with soda ash to form an insoluble Copper Carbonate solid that can be scooped up.
Waste Disposal Do not reuse container. Comply with Federal, State and local regulations. Sweep up crystals, powder or insoluble Copper Carbonate and dispose of in an approved landfill.
Environmental Effects May be dangerous if it enters the public water systems. Follow local regulation. Toxic to fish and plants. Fish toxicity critical concentration is 235 mg/l and plant toxicity is 25 mg/l.
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SECTION IX. SPECIAL PRECAUTIONS
Storage Store in a dry place.
Other Precautions None other than those stated in the MSDS or on the package.
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SECTION XI. REGULATORY INFORMATION
NOTICE: The information herein is presented in good faith and believed to be accurate. However, no warranty, expressed or implied, is given. Regulatory requirements are subject to change and may differ from one location to another. It is the buyer’s responsibility to ensure that its activities comply with Federal, State and local laws.
U.S. REGULATIONS: SARA 313 Information. This product contain the following substance subject to the reporting requirements of Section 313 of Title III of the Superfund Amendments and Reauthorization Act of 1986 and 40 CFR Part 372: COPPER COMPOUND 63.3%.
SARA HAZARD CATEGORY: This product has been reviewed according to the EPA "Hazard Categories" promulgated under Sections 311 and 312 of the Superfund Amendments and Reauthorization Act of 1986 (SARA Title III) and is considered, under applicable definitions, to meet the following category: AN IMMEDIATE HEALTH HAZARD.
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