Chemistry

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Chemistry - $5

I need to plot the observed emf in mV vs logarithm of ppm F to obtain a calibration curve. From a prepared stock solution of 100 mL and the KCl molarity is 0.1M for it. From dilution of this solution, a 20 ppm, 10ppm, 5ppm, 2.5ppm, and 1.25 ppm were made. Im not sure how to go about setting this up. The weight of NaF used was 221 mg and the emf data for the dilutions are: 20ppm=276 mV , 10ppm=279 mV , 5ppm=284 mV , 2.5ppm= 289 mV , 1.25ppm=297 mV.
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Allicin - $4

Allicin is the compound responsible for the characteristic smell of garlic. An analysis of the compound gives the following percent composition by mass: C: 44.4 percent; H: 6.21 percent; S: 39.5 percent; O: 9.86 percent. Calculate its empirical formula. What is its molecular formula given that its molar mass is about 486g?
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Chemical Questions - $6

12. Regarding the acid-base neutralization reaction Mg(OH)2 (aq) + 2 HNO3 (aq) ? 2 H2O (l) + Mg(NO3)2 (aq), which of the following statements is true? (Points : 5) Mg(OH)2 is the acid and HNO3 is the salt Mg(OH)2 is the base and H2O is the salt HNO3 is the base and Mg(NO3)2 is the salt HNO3 is the acid and Mg(NO3)2 is the salt ...
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Chemistry - $8

When 500.0 mL of 0.10 M NaOH solution (containing Na+ and OH- ions) is mixed with 500.0 mL of 0.10 M Mg(NO3)2 solution (containing Mg2+ and NO3- ions) a precipitate of solid Mg(OH)2 forms, and the resulting aqueous solution has pH = 9.43. Based on this information, determine the value of Ksp for Mg(OH)2. Show your reasoning clearly. Problem 2 0.30 moles of HOCl are added to sufficient water to make 1.0 L of solution at 25 C. Finish the table The Ka of HOCl, at 25 C, is 2.9 x 10-8, determine x. ...
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Chemistry 121 Lab - $6

Lab 10?Concept Map of Chemistry 121 Major Topics Lab 10 Expectations Concept Mapping Resources Directions: Everyone should visit the first link to gain a general understanding of what concept mapping is, how to create a concept map, and the reasons for creating and using concept maps. Then, everyone will need to download concept mapping software to use for this assignment. Two options are provided below (you only need to download one form on concept mapping software, not both!). Link 2 will direct you to free software. Link 3 will direct you to a free 30 day trial of a different software package. Please investigate both Link 2 and Link 3 before making your decision about which software to download! Questions? Just ask! 1. The following website provides a clear explanation of how to develop a concept map. In addition, this website shows you several examples of concept maps. Finally, the website contains links to other websites that you may want to investigate:
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Chemistry in Medicine or Chemistry in the Environment - $5

Decide whether you would like to study Chemistry in Medicine or Chemistry in the Environment. Then, carefully read each of the links under that topic, below. Chemistry in Medicine?? Chemistry in the Environment?? Reading: You may focus your reading on EITHER the chemistry in medicine links OR the chemistry in the environment links. Whichever category you choose, please read the websites under that category carefully! Please select which of these two topics you would like to study, read the links related to that topic. 1.Decide whether you wish to study chemistry in medicine or chemistry in the environment . 2.Post a one-paragraph summary of the link/article of your choosing from the options listed below within whichever category you decide (related to your selected topic).
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DNA Analysis via Gel Electrophoresis - $10

Lab 9 DNA Analysis via Gel Electrophoresis Introduction: Gel electrophoresis is an important analytical technique in the fields of chemistry and biochemistry. In this virtual experiment, we will explore the process of using gel electrophoresis to analyze DNA samples. Your report for this lab should be submitted to the Lab 9 dropbox by the last day of the unit. Have fun! Experiment: Go to http://learn.genetics.utah.edu/units/biotech/gel/ and slowly begin to work through the gel electrophoresis virtual lab, taking careful notes. Estimated time required: 1 hour. In your lab report, answer the following prompts in complete, well developed sentences. Be sure to paraphrase the prompts themselves into your responses, so that your answers make sense.
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Chemical Questions - $3

1) From the perspective of a chemist, explain what a crystal is. Choose two examples of crystals, and explain how they are chemically similar to and different from one another. 2) Explain the relationship between vapor pressure and the common phases solid, liquid, and gas.
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Chemical Exercises - $4

Prepare written answers to the following exercises: 1. Adapted from Exercise 36 in Ch. 11 of Introductory Chemistry: A marine biologist may need to dive deep underwater for her research. To do so, she may want to know how to do calculations related to pressure and volume changes that occur, depending on the depth of the dive. Suppose she inhales air at a depth of 60 meters and at a pressure of 6 atm. Holding her breath, the marine biologist then ascends to a depth of 10 meters (where the pressure is now 2 atm). What volume would the air in her lungs expand to? 2. Environmental health and safety departments employ many environmental scientists to monitor and regulate business practices. Imagine that you work for the Environmental Protection Agency (EPA) to ensure that gas canisters are correctly pressurized. ...
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Radiocarbon Dating - $8

Lab 8: Radiocarbon Dating? Background: ?In this virtual laboratory activity, we will investigate radiocarbon dating (also called carbon-14 dating), a very important and useful chemistry application. Your laboratory report should be saved as a .doc file, and should be submitted to the Lab 8 dropbox by the last day of the unit. Questions? Just ask!??Laboratory Procedure:1. Go to this website. (http://www.sciencecourseware.com/VirtualDating/files/RC0/RC_0.html) You will notice that the website contains 12 pages (12 screens). In order to advance from one page to the next, you first need to correctly answer each of the questions on the current page.
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Radiocarbon Dating - $7

Lab 8: Radiocarbon Dating? Background: ?In this virtual laboratory activity, we will investigate radiocarbon dating (also called carbon-14 dating), a very important and useful chemistry application. Your laboratory report should be saved as a .doc file, and should be submitted to the Lab 8 dropbox by the last day of the unit. Questions? Just ask!??Laboratory Procedure:1.

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Hess Law Report - $6

Hess Law Review the safety materials and wear goggles when working with chemicals. Read the entire exercise before you begin. Take time to organize the materials you will need and set aside a safe work space in which to complete the exercise. Experiment Summary: Students will have the opportunity to measure temperature changes taking place in a calorimeter during neutralization reactions and use the measurements to calculate enthalpy of reaction.They will illustrate the validity of Hazy Law by comparing the values of enthalpy of two chemical reactions...
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Fats, soaps and detergents- A saponification reaction - $5

These questions are from an experiment: Fats, soaps and detergents- A saponification reaction 1. The triglyceride and the glycerol differ with respect to polarity and H-bonding. Discuss these two differences in terms of their chemical structures.We made our own soap and added cottonseed oil, CaCl2, FeCl3, and HCl ( to change solution to ph 4) to see their effects. When I added the CaCl2 a precipitate formed 2. Write an equation for the formation of any precipitate.When i added the HCl, the solution became cloudy 3. Write an equation for any changes observed.
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Chemistry Questions - $4

A) What are the advantages and disadvantages of writing a chemical equation with chemical symbols and formulas instead of just words? B) On your own words summarize to another person the steps needed to successfully write a balanced chemical equation. C) Describe the basic part of a chemical equation. Identify how the physical state of elements and compounds is identified in an equation.
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