Hydrogen From Electrolysis of Water Using Solar Energy
9. Assume that due to dwindling supplies of crude oil and natural gas, the US embarks on a plan to implement the "hydrogen economy" for which hydrogen will be generated by electrolysis of water. The source of electricity is from photovoltaic (PV) conversion of sunlight in the southwestern US. (a) Assume that a flat plat ...continues
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 ...continues
Spike Recovery of Trimethylbenzene from Soil and Analysis with GC-FID
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.
Environmental Chemistry : NOEl, Redox Potential and Molar Concentration of OH in Air
1. The threshold/NOEL level found for a particular chemical from animal studies is 0.004 mg/kg body weight per day. The only source for the chemical is freshwater fish, where it occurs at an average level of 0.2 ppm. What is the maximum average daily consumption(g) of such fish that would keep exposure level below the ADI or RfD ...continues
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 co ...continues
Dissolved Hydrogen Sulfide in Marsh Water
(a) Anaerobic bacteria living at the bottom of a shallow inlet to a salt marsh are generating hydrogen sulfide as a by product of their metabolism. Although this compound is ordinarily found as a gas, it is reasonably soluble in water. What is the maximum concentration of dissolved hydrogen sulfide species (H2S, HS-, and S2-)t ...continues
The PCB concentration in Lake Michigan is declining according to a first-order rate law having a rate constant of 0.050 per year. If the PCB concentration in Lake Michigan averaged 0.47 ppt in 1991, what will it be in 2005? In what year will the concentration fall to 0.10 ppt? What is the half-life period of PCBs in this lake? ( ...continues
Photosynthesis and fixed carbon
Please provide detailed steps. a) Photosynthesis is estimated to produce 350.0 g (dry weight) of plant matter per square meter, 50% of which is carbon. Calculate the total number of grams of carbon "fixed" each year by 1000 square meters. b) The photosynthetic reaction can be represented as: 6CO2 + 6H2O -> C6H12O6 + 6O2 Of ...continues
Assume that the wet limestone process requires 1 metric ton of calcium carbonate to remove + 85.0 % of the sulfur from 4 metric tons of coal containing + 10.0 % S Assume that the sulfur product is calcium sulfate. Calculate the percentage of the limestone converted to calcium sulfate.
Have looked at multiple solutions and still can't get right. Please provide solution and steps. How many metric tons of 5% S coal would be needed to yield the H2SO4 required to produce a 4.5 cm rainfall of pH 2.00 over an area of 100 square kilometers? Hint: Calculate vol rain, mol H+, mass of S, mass of coal
