ture content determination? What are the USP and NF official methods of determining moisture content? Give their advantages and disadvantages. What are the reasons for drying the plant material before using? Enumerate the advantages and disad

ture content determination? What are the USP and NF official methods of determining moisture content? Give their advantages and disadvantages. What are the reasons for drying the plant material before using? Enumerate the advantages and disad

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter4: Energy And Chemical Reactions

Section: Chapter Questions

Problem 123QRT

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Ethylene (CH₂CH₂) is the starting point for a wide array of industrial chemical syntheses. For example, worldwide about 8.0 × 10¹0 kg of polyethylene are made from ethylene each year, for use in everything from household plumbing to artificial joints. Natural sources of ethylene are entirely inadequate to meet world demand, so ethane (CH3CH3) from natural gas is "cracked" in refineries at high temperature in a kinetically complex reaction that produces ethylene gas and hydrogen gas. Suppose an engineer studying ethane cracking fills a 80.0 L reaction tank with 14.0 atm of ethane gas and raises the temperature to 850. °C. He believes K₂=0.60 at this temperature. alo Calculate the percent by mass of ethylene the engineer expects to find in the equilibrium gas mixture. Round your answer to 2 significant digits. Ar Note for advanced students: the engineer may be mistaken about the correct value of K, and the mass percent of ethylene you calculate may not be what he actually observes. % 0x₁…
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Ethylene (CH₂CH₂) is the starting point for a wide array of industrial chemical syntheses. For example, worldwide about 8.0 × 10¹0 kg of polyethylene are made from ethylene each year, for use in everything from household plumbing to artificial joints. Natural sources of ethylene are entirely inadequate to meet world demand, so ethane (CH₂CH3) from natural gas is "cracked" in refineries at high temperature in a kinetically complex reaction that produces ethylene gas and hydrogen gas. Suppose an engineer studying ethane cracking fills a 35.0 L reaction tank with 35.0 atm of ethane gas and raises the temperature to 400. °C. He believes K₂=0.20 at this temperature. Calculate the percent by mass of ethylene the engineer expects to find in the equilibrium gas mixture. Round your answer to 2 significant digits. Note for advanced students: the engineer may be mistaken about the correct value of Kp and the mass percent of ethylene you calculate may not be what he actually observes.
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From the discussion question from Module 5, recall the chemical equation for the combustion of gasoline (iso-octane, C8H18) is: 2C8H18 + 25O2 ---> 16CO2 + 18H2O This means that 2 moles of iso-octane combine with 25 moles of CO2 to produce 16 moles of CO2 and 18 moles of water. This is important for understanding the impact of fossil fuel use on the atmosphere because burning one mole of fuel adds a lot of CO2. Thinking about this in terms of the stoichiometry, and change in concentration, suppose we had 1.0 mole of iso-octane dissolved in 1.0 m3 of atmosphere. That means the concentration of carbon-containing molecules would be 1 mole per cubic meter. However, ff we burned all that iso-octane and convert the C8H18 into CO2 the concentration of carbon-containing molecules increases. How much does the concentration of carbon-containing molecules increase if 1.0 mole of C8H18 in 1.0 m3 of air is converted into CO2 as shown in the chemical equation above?
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Absorbance (arb.units) SA 8.3 B-Carotene Calibration Curve 2004 65,03UM 3.26 mM 5,06 nM y=(105612 Mx-0.1736 2.94 M 4304 1064 ENY 181 121 Concentration (M) 1004 5 Abserbence (arb.units) 200 0.25 300 A student creates a standard curve of B-Carotene and plots the line of best fit. They then measure the absorbance of a solution of B-Carotene with an unknown concentration. What is the concentration of the sample? You can assume they used a cuvette with a pathlength of 1 cm. 400 500 600 Wavelength (nm) YOU
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