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
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.
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
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
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
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 -
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
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.
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
At an altitude of 40.00 km, the average atmospheric temperature is essentially 0 degrees C. What is the average number of air molecules per cubic centimeter of air at this altitude? Hint: Solve the equation for the pressure as a function of height and temperature and from this use the ideal gas equation to calculate the volume
What is the objection to using chlorine gas to disinfect wastewater effluent, and suggest two alternative substances that can be used without causing this problem.
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.
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?
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
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
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?
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
The questions are in the attachment. Question 2: Uranium, symbol U, is one of the rarer elements in the earth's crust, where it occurs mainly as the oxide uraninite (U3 08 ). In 1938, Otto Hahn and Fritz Strassmann showed unambiguously that new, lighter, elements are formed when Uranium is bombarded with neutrons, a proces
What are two health effects and two commonly used treatment technologies for 1. Chromium 2. MTBE 3. Sulfate?
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?
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
What technology or combination of technologies would you recommend for treating sulfur dioxide contaminated air streams? Could you include a brief description of the recommended technology.
Why are contaminant chemical properties important in selecting environmental technologies?
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.
What are the advantages and disadvantages of animal studies and epidemiological studies for establishing dose-response relationships?
Average daily dose: only need the water ingestion completed
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
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
What's an example of an environmental pollutant that does not directly react with the human body?
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