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    Environmental Chemistry

    Concentration: Zinc and Toluene

    1. 2g sample of harbour sediment was digested in aqua regia and then the filtered solution made up to 50mL and analysed by flame atomic absorption, giving a concentration of 4.6mg/L of Zinc. What was the concentration of Zinc, in mg/Kg in the sediment? 2. 100µL sample of petrol for analysis was diluted to 10mL with pentane c

    Spike Recovery of Trimethylbenzene from Soil and Analysis

    1g soil has been spiked with 0.1ml of 100 ppm (v/v) trimethylbenzene and subsequently extracted with 250 mL pentane. The extract is then measured with GC-FID. Calculate the recovery when the extract gives a peak area for trimethylbenzene of 750, while 20 ppm solution of trimethylbenzene gives a peak area of 50000.

    Dealing with Hazardous Waste

    7. Give your reasons for agreeing or disagreeing with each of the following proposals for dealing with hazardous waste: A. Reduce the production of hazardous waste and encourage recycling and reuse of hazardous materials by charging producers a tax or fee for each unit of waste generated. B. Ban all land disposal and incin

    Time Weighted Average of Chemical Exposure

    An industrial hygiene survey has been conducted to determine whether exposure of workers to ethyl benzene (molecular weight 106) exceeded the OSHA PEL of 100 ppm. The exposure time and levels are: Period of Time Average Hourly Exposure 8:00-10:00 am 90 ppm 10:00-1

    Global Warming, Climate Change and Albedo

    1.In preparation for the 1992 UN Conference on the Human Environment in Rio de Janeiro, President George H. W. Bush's top economic adviser gave an address in Williamsburg, Virginia, to representatives of governments from a number of countries. He told his audience not to worry about global warming because, the average temperatur

    OSHA Permissible Exposure Limits

    Q1. Suppose that an industrial process produces the following air-contaminant concentrations for the periods shown: Period Methanol(ppm) Nitric Oxide(ppm) Sulfur Dioxide 8AM - 10 AM 50 5 0 10AM - 11 AM 150 10 1 11 AM -

    Adsorption of Heavy Metals in Soil : Langmuir Equation

    A peat soil was found to have the following Langmuir constants for the adsorption of heavy metals. Metal Q (adsorption capacity) k (Langmuir reaction energy) Lead (Pb2+) 36.5 1.096 Cadmium (Cd2+) 10.6 0.483 Chromium (CrO42-) 6.8 0.330 Langmuir adsorption equation qe = QkCe / (1+ kCe) Where qe is met

    Use of plastics in everyday life

    Discuss how plastics are used in everyday life and cutting edge technology and what the pitfalls are of plastics. The word limit is 300 words. Cite your sources.

    Comparing the Amount of Coal and Uranium Required to Produce Electricity

    When some large nuclear plants run at full capacity, they produce about 1900 MW of electrical power. At this rate, what mass of 235U (kg) would it consume per year if the efficiency of converting nuclear energy to electricity is 33%? How many metric tons of coal would be required to supply the same amount of electricity? Hint

    Sediment Sample of Clay

    A sediment sample of clay was equilibrated with ammonium ion (NH4+). The ammonium ion was then displaced with Na+. The total amount of ammonium that had been adsorbed by the sediment sample was 55.8 milliequivalents (meq) and the sample had a dried mass of 82.4 g. Calculate the cation exchange capaciticy (CEC) in meq/100g.

    Stratifiction (Layers) in a Body of Water

    Draw a diagram showing the stratification in a body of water. Label the different layers and describe the type of chemistry (and species) that occurs at each level. I do not know how to draw the diagram and what layers to include?

    Chemistry - Amount of Gold in Sea water

    Extracting gold from seawater: How many grams of Au are there in the whole ocean? With a 60% recovery possible, how many liters of seawater must be processed for gold to obtain 1 kg of that metal? - MW of Au = 196.967 gram/mole - Avg. seawater concentration of Au = 2.5 x 10^-11 mole/kg of seawater - mean density of s

    The radioactive decay of Cesium-137 sample

    1. Following a terrorist release of Cesium-137 (half-life of 30 years) in downtown, clean up efforts were successful in removing all but 100 curies. How long will it take for the contamination to decay to about 5 curies? A. 90 years B. 130 years C. 175 Years D. 215 years please explain

    positional congeners of polychlorinated aromatics

    Why do the geometric dimensions of TCDD make it so toxic? Why is toxicity diminished in other congeners where chlorines are removed from the 2,3,7,8 positions, or when chlorines are added to remaining positions on the rings?

    Solubility Rules applied to various reactions

    Use the Solubility Rules to write net ionic equations for the reactions that occur when solutions of the following are mixed. a) K2S + ZnSO4 b) K2CrO4 + NiCl2 c) CsOH + FeCl3 [2] d) CuSO4 + Pb(ClO4)2 e) FeSO4 + K3PO4 f) FeCl2 + TlNO3 g) (NH4)2CO3 + Ni(ClO4)2

    Nitrogen Content in Water

    What method I could in a academic chemical laboratory to determine the nitrogen content in water? How could I then determine the quality of the water?

    Contaminated Air Stream

    What technology or combination of technologies would you recommend for treating the following contaminated air streams? Include a brief description of the recommended technology: (a) 0.05 to 20 micron particulates along with 800 ppmv of chlorinated solvent

    Development and use of Freon

    How were FREONS developed for use in refrigeration? What were the advantages of these chlorofluorocarbons over previously used cryogens? Outline why the use of FREONS has now been discontinued.

    Toxic effects of HCN

    In less than a 125 words, with Hydrogen Cyanide -How can we most likely be exposed to it -How we can minimize our dose -the most likely route of entry into the body and target organ -A brief description of its toxic effect hide problem

    Ozone Depletion Potential (ODP)

    Please see attachment for the problem. Estimate the ODP (i.e.) Ozone Depletion potential for the following CFC alternatives relative to HCFC-22. and fill in the table with the ODP values. Justify the reasons for your ranking. Compound kOH × 1012 cm3 molecule-1 s-1 ODP CHF2Cl (HCFC-22) 1.2 exp (-1650/T) 0.05 CF3CH2F (HFC-13

    Benzene and Phenol: Discussion of LD50 and LDLO

    With Benzene and Phenol: Does one molecules consistently have a greater LD-50 for all species? explain Are the relative LDLO for benzene and phenol as you would expect? How were the LDLO for humans obtained? How reliable are the LDLO? Explain which data you would use to determine a lethal dose for you and calculate the