9.9 Forensic Chemistry (1-i) Outline precautions that may be necessary to ensure accuracy and prevent contamination of samples for analysis There are three main sources of contamination 1. Addition of extraneous material, during collect, handling and transport such as soil etc. Precautions for this include using sealed containers, clean sterile utensils 2. State of laboratory- the cleanliness of the lab, including quality of air, presence of dust and other contaminants 3. Careless analysis- not wearing protective clothing such as gloves and coat and result in the adding of sweat, dandruff etc.
Prelaboratory preparation: Read pages 1 – 30 and 45 – 54 of the lab text. You may disregard the microscale distillation procedures of TECH 0704. Answer in your laboratory notebook the Safety Quiz on pages 11 – 12 and the Prelab Questions 1, 2a, 2b, 3 -5, pp. 67 - 68. EXPERIMENT: TECH 0704, Distillation, macroscale technique only, simple and fractional: Substitute a mixture of 25 mL ethanol and 25 mL water for the toluene/cyclohexane mixture.
... Investigate the heating/cooling curves 4. SCORING : Phase Changes - POGIL http://www.pogil.org/uploads/media_items/phase-changes.original.pdf • Heating / cooling curves Prerequisites • Temperature (average kinetic energy) • Phases of matter: solid, liquid, gas • Molecules • Endothermic Heating and Cooling Curves - Glastonbury https://www.glastonburyus.org/staff/BREINANH/conceptual/labs/Documents/Heating.ice.lab.student.doc Procedure obtaining a heating curve of H20 with Lab Pro ... LabPro Dr. Breinan Chemistry p. 2. max. Figure 1 ... Heating and Cooling Curves ...
(50cm3 exactly), and pour the water into the copper calorimeter beaker. 6. Put the thermometer into the water (it should not touch the copper beaker) and record the temperature of the water at the start. 7. Hold the needle (with the nut), with a pair of tongs and set the nut on fire using the spirit lamp.
They should also never be used for bacterial or fungal work. The hoods are equipped with a short-wave UV light that can be turned on for a few minutes to sterilize the surfaces of the hood, but be aware that only exposed surfaces will be accessible to the UV light. Do not put your hands or face near the hood when the UV light is on as the short wave light can cause skin and eye damage. The hoods should be turned on about 10-20 minutes before being used. Wipe down all surfaces with
* Wash raw vegetables and fruits thoroughly before eating, especially those that will not be cooked. Avoid eating alfalfa sprouts until their safety can be assured. Methods to decontaminate alfalfa seeds and sprouts are being investigated. * Drink only pasteurized juice or cider. Commercial juice with an extended shelf life that is sold at room temperature (juice in cardboard boxes, vacuum sealed juice in glass containers) has been pasteurized, although this is generally not indicated on the label.
CHE 326 Experiment 2 Nitration of Methyl Benzoate I. PRE-LAB (please complete before coming to lab, should be typed, 1 page limit) [pic] A. Table of Reagents (fill in all the blanks as described in the instructions). |Compound |Mol. Weight |mmol |amount |melting point |density |Ref. | | | | |(in g or mL) | | | | |methyl benzoate | | | | | | | |nitric acid | | | | | | | |sulfuric acid | | | | | | | |methanol | | | | | | | |methyl 3-nitrobenzoate | | | | | | | B. References (provide references for the information you've given in the table of reagents) C. Safety (are any of the reagents used toxic or hazardous?
The solutions that my group chose to test were salt, sucrose, and rubbing alcohol. Rubbing alcohol is a clear, colorless, liquid with a distinctive odor. It is irritant to body tissue and you should seek medical attention if it touches your skin or eyes. It is a class 1 B flammable liquid. Salt is odorless and is slightly toxic by ingestion.
6. Clean up! Do NOT put any solution into sink or garbage. Data Collection: Mass of empty beaker: | 163.49 g | Mass of beaker & hydrated copper (II) sulphate | 166.5 g | Mass of beaker & anhydrous copper(II) sulphate | 165.65 g | Analysis: Conclusion: This lab brought forth many potential sources of error, preventing a completely accurate or precise final result. When using the glass rod to stir the powder, much of the powder was transferred onto the rod and therefore mass was lost.
 Allows complete surface contact during decontamination procedure.  Requires trained staff.  DISINFECTION :  Will destroy microorganisms but not bacterial spores.  Not necessarily kills all microbes present but reduces them to harmless levels.  Should only be used if heat treatment is impractical or harmful to the material.