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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

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?

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

Box Model for Steady-State Pollution Concentration

A Power plant is the main point source of SO2 emissions for a 25 km2 area. Estimate the steady-state concentration of SO2 for this area from this point source given the following temperature data. Windspeed= 5km/hr. The concentration of SO2 is 111.1 g/s. Height (in meters) Temperature (K) 0 300 500

Graphing SO2 Concentrations around a Power Plant

1) A power plant burns 10^4 kg hr-1 of coal containing 2.5% sulfur. The effluent is released from a single stack of height 70 m. The plume rise is normally about 30 m. The wind on the day of interest, which is a sunny summer day, is blowing at 4 m s-1. There is no inversion layer. a) Plot the ground-level SO2 (sulfur dioxid

Calculate how much energy a wind turbine produces in a year.

Assume a wind turbine with a hub 50 meters above the ground, a rotor diameter of 40 meters and a wind-conversion efficiency of 25 percent. The turbine operates in an area with an average wind-power density of 550 watts/sq meter at 50 meters altitude. How much electricity (kwH) can the turbine generate per year? Wind densities

Concentration of Iron in a Waste Stream

The determination of iron in industrial waste stream is often carried out by reacting the water sample with o-phenanthroline to form a red-orange complex that absorbs at 510 nm. Using the data shown in the following table construct the standard calibration curve and determine the concentration of Fe in the waste stream. The cuve

Grams of Lithium Carbonate Formed

(a) Aqueous lithium hydroxide solution is used to purify air in spacecrafts and submarines because it absorbs carbon dioxide according to the equation: 2LiOH(aq) + CO2(g) -> Li2CO3(aq) + H2O(l) The pressure of CO2 in a cabin with a volume of 2.4 x 105 L is 7.9 x 10-3 atm at 312 K. A solution of LiOH of negligible volume is

Bubbles and Bicarbonate

(a) A small bubble rises from the bottom of a lake, where the temperature and pressure are 8ºC and 6.4 atm, to the water's surface, where the temperature is 25ºC and pressure is 1.0 atm. Calculate the final volume (in ml) of the bubble if its initial volume was 2.1 ml. (b)The percent by mass of bicarbonate (HCO3-) in a

Will Banning Phosphate Builders Slow Eutrophication?

Assume that algae need carbon, nitrogen and phosphorus in the atomic ratio 106:16:1. What is the limiting nutrient in the lake that contains the following concentrations: total carbon = 20 mg/L, total N = 0.80 mg/L and total P = 0.16 mg/L? If it is known that half the phosphorus in the lake originates from the use of phosphate d

An area-source box model for air pollution above a peninsula of land

37) Consider an area-source box model for air pollution above a peninsula of land. the length of the box is 15 km, its width is 80 km, and a radiation inversion restricts mixing to 15 m. Wind is blowing clean air into the long dimention of the box at 0.5 m/s. Between 4 and 6 pm there are 250,000 vehicles on the road, each being

Estimate of NOx concentration given emission volume and wind speed.

36) A freeway has 10,000 vehicles per hour passing a house 200 m away. Each car emits an average of 1.5 g/mi of NOx, and winds are blowing at 2 m/s across the freeway towards the house. Estimate the NOx concentration at the house on a clear summer day near noon (assuming that NOx is chemical stable).

Tetrachloroethylene Biochemical Oxygen Demand problem

Info: BOD: Biochemical Oxygen Demand BOD5 is the total amount of oxygen consumed by microorganisms during the first five days of biodegradation BOD5 = (DOi - Dof)/(P) this is the five-day BOD of a diluted sample Where DOi = the initial dissolved oxygen (DO) of the diluted wastewater DOf = the final DO of