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

World of Chemistry

7th Edition

ISBN:9780618562763

Author:Steven S. Zumdahl

Publisher:Steven S. Zumdahl

Chapter10: Energy

Section: Chapter Questions

Problem 38A

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The heating of CuSO4. 5H2O(S) yields several transitions as a function of temperature. The table below gives the percentage of original mass lost as a function of the approximate temperature. Use these percentages to determine the sequence of decompositions and write chemical equations for each transition. percentage of original mass lost 14.5 29.0 36.0 51.5 67.0 70.5 approximate temperature (Degree C) 100 130 220 800 910 1020
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…
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.
When two different liquids are mixed or when a gas or solid is dissolved in a liquid, bondsare broken between neighbouring molecules (or sometimes atom) in the feed materials,and new bonds are formed between neighbouring molecules (or ions) in the productsolution. i. Briefly distinguish between heat of solutions and standard heat of formation of solution.ii. Consider solid X is to be dissolved in solvent Y. If ΔH°f is the heat of formation of X(s),using the appropriate notations, write an equation to calculate the standard heat of formation of solution that contains 5 mol of X in 100 mol of Y at 25°C, relative to X and Y.
Write a balanced chemical equation for the reaction that occurs when crotonaldehyde, C3Hs COH(1), is combusted in air. Express your answer as a balanced chemical equation including phases. ΑΣΦ IWD ? A chemical reaction does not occur for this question.
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?
The FDA-recommended daily allowance for fat in a 2,000 calorie diet is 77g. A. What is the max number of Calories which come from fat while still following this guideline? What is the total percent of daily allowance that can come from fat? The Atwater System provides a generalized value of 9.1 Cal/g of fat. B. Write the chemical equation and calculate the enthalpy of the combustion of stearin( C57H11006). 1 cal = 4184 Joules
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
A large population of Japanese beetles infests a plot of cropland. In response to the infesta tion, farmers treat the land with organochlorine pesticides. As a result of the treatment, the population of Japanese beetles is eradicated within the cropland, along with the popula- tions of multiple other insect species. Which of the following statements explains the most likely reason for the death of so many insect populations? Organochlorine pesticides are persistent organic pollutants that interfere with the respi- ratory system of the insect populations. Organochlorine pesticides are endocrine disruptors that interfere with the growth hor- mones of the insect populations. Organochlorine pesticides are persistent organic pollutants and interfere with the re- productive organs of the insect populations. Organochlorine pesticides are endocrine disruptors that interfere with the transmission of nerve impulses, resulting in spasms, seizures, and death of the insect populations.
Complete combustion of 5.50 g of a hydrocarbon produced 17.7 g of CO, and 6.03 g of H, O. What is the empirical formula for the hydrocarbon? Insert subscripts as necessary. empirical formula: CH SPECIAL ΔΣΩ λμπ (s) (1) (aq) -> (g) () [ ] -> 1. CLR 3,438 19 SA stv W MacBook Air
A student wrote the following equation C6H12O6(s) + 602(g) → 6CO2(g) + 6H₂O(g) + energy Based on the fact that water vapour is a product, the logical conclusion is that the equation represents: Select one: Ophotosynthesis in an open system cellular respiration in a closed system combustion in a closed system combustion in an open system
(a) The atomic weight of carbon is 12, hydrogen is 1 and oxygen is 16, and the formula for the combustion of methane (CH4) is given by : CH4 + 2 O2 –→ CO2 + 2 H2O + energy A mole of methane releases 810 KJ of energy on burning. Calculate the weight of carbon dioxide produced by burning 5kg of methane. Identify an alternative gas for combustion that produces less carbon dioxide than methane and state how it is generated.