CHE 2B- Final Exam Guide - Comprehensive Notes for the exam ( 25 pages long!)

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CHE 2B Full Course Notes

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Chemical equilibrium: reactants products, at equilibrium there is a balance between reactants converting into products and products converting into reactants. Outline: definition and examples of chemical equilibrium, equilibrium constants, gas phase equilibrium, chemical activity, heterogeneous equilibrium, calculations using the equilibrium constant, equilibrium problems, le chatelier principles. Hgcl2(s) > hg2+(aq) + 2cl-(aq: equilibrium of chemical reactions, condensation of ammonia haber process . Equilibrium constant: consider a generic reaction aa + bb cc +dd, the equilibrium constant is defined as: [] indicates concentrations: large kc indicates that equilibrium is shifted toward the products. The meaning of equilibrium constants: kc > 0 always! If kc >> 1 then equilibrium is strongly shifted to the product side. If kc ~ reactants and products are balanced at equilibrium. If kc ~0 then equilibrium is strongly shifted to the reactants side: example, hydrogen gas reacts with iodine gas to form hydrogen iodide hi(g) at. T=750 c. find kc from the equilibrium gas concentrations:

Related Questions

Decomposition of Malachite

Here is what Malachite is Made Out Of

Malachite is a famous and very popular semi-precious stone. Its banded light and dark green bands are one-of-a-kind, and give it a unique ornamental quality unlike that of any other stone. The light and dark green bands are so distinctive that malachite may be one of the most easily recognized minerals by the general public. Malachite is popular in jewelry, especially Native American southwestern jewelry. The stones inlayed in silver make a nice alternative to traditional turquoise jewelry.

Malachite is a form of copper carbonate with the molecular formula Cu₂CO₃(OH)₂. When heated to around 200 ï¿½C, malachite decomposes into copper (II) oxide (CuO) and other products.

Reaction Stoichiometry

The Law of Conservation of Mass states that matter can neither be created nor destroyed. Therefore, the number of atoms of each element on the reactants side must be same as the number of atoms on the products side. This quantitative study of chemical reactions is called stoichiometry. The substances in a balanced reaction are related to each other by stoichiometric molar ratios. For example, magnesium reacts with hydrochloric acid in a 1:2 stoichiometric ratio in the balanced equation below.

Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)

The molar ratios can be used as conversion factors to find the amount (in moles) of one substance given the amount of another. For example, given the number of moles of HCl, the amount of MgCl₂ can be determined as shown below.

nMgCl2=nHCl x (1mol MgCl2) / (2mol HCL)

The molar ratios are used to determine the amount in moles. However, the amount of reactant or product is often measured in grams. Mass can be converted to moles and vice versa as shown below.

n = m / (MM)

m = n x MM

where n is the number of moles, m is the mass of the product in g, and MM is its molar mass in g/mol.

To observe the Law of Conservation of Mass, you can perform different types of chemical reactions. For example, you can use a decomposition reaction to observe one compound being broken down into two or more elements or new compounds. For this reaction to take place, you must break existing bonds within the starting compound. Different sources of energy such as heat, light, or electricity may be used. Through a decomposition reaction, you can observe that the atoms in the original compound are not destroyed but are rearranged to form simpler substances, such as elements or compounds.

About This Lab

In this lab, you will test if the relationship between malachite and copper (II) oxide is stoichiometric. To do this, you will heat a known mass of malachite to produce copper (II) oxide. You will then compare the amount of copper (II) oxide obtained experimentally with the amount of copper (II) oxide expected from the balanced equation for the decomposition reaction.

1.Take a crucible from the Containers shelf and place it on the workbench.

2.Take a balance from the Instruments shelf and place it on the workbench.

3.Move the crucible onto the balance. Record the mass of the empty crucible to the nearest 0.001g in your Lab Notes.

4.Move the crucible onto the workbench.

5.Take copper (II) carbonate hydroxide from the Materials shelf and add 10 g to the crucible.

6.Move the crucible onto the balance and record the mass of the crucible containing copper (II) carbonate hydroxide in your Lab Notes.

7.Take a Bunsen burner from the Instruments shelf and place it on the workbench.

8.Move the crucible onto the Bunsen burner.

9.Double-click on the crucible to open its properties. Select Show Contents and click OK. This gives you a cut-away view of the crucible's contents.

10.Turn the Bunsen burner on to low flame by clicking the knob at the bottom once. Clicking multiple times will increase the intensity of the flame until it is turned off.

11.Watch the crucible until the malachite fully decomposes. You will see a distinct color change.

12.Move the crucible onto the workbench to cool.

13.Turn off your Bunsen burner.

14.Weigh the crucible with its contents and record the mass to the nearest 0.001 g in your Lab Notes.

Clear your station.

Lab Notes:

Numbers below refer to numbers in the above âAbout this Labâ

3. Empty crucible = 88 g

5. Added 10 g of Copper (II) carbonate hydroxide to crucible

6. Crucible with Copper (II) carbonate hydroxide = 98 g

11. to Black

14. after heating crucible with its contents = 95.195

Questions I have answered:

How many grams of malachite did you add to the crucible? 10g

How many grams of product were in the crucible after heating? 7.195

By how much did the mass of the crucible's contents change after heating? -2.805

The molar mass of malachite is 221.1 g/mol. How many moles of malachite were present before the reaction? 0.04523 mol

The product remaining in the crucible after heating is copper (II) oxide. The molar mass of copper (II) oxide is 79.55 g/mol. How many moles of copper (II) oxide were produced during the reaction?

0.0945 mol

Please answer the following:

Q1 a. Which of the following represents the balanced chemical equation for this reaction?

Cu2CO3(OH)2=2CuO+H2O

Cu2CO3(OH)2=CuO+CO2

Cu2CO3(OH)2=2CuO+H2O+CO2

Cu2CO3(OH)2=CuO+H2O+CO2

b. Based on the number of moles of malachite that you started with, how many grams of water were produced? The molar mass of water is 18.0153 g/mol. Choose the closest answer.

1.815 g 0.8148 g 1.630 g 1.982 g

c. Based on the number of moles of malachite that you started with, how many moles of CO₂were produced? Choose the closest answer.

1.000 mol 0.04523 mol 0.9000 mol 0.09045 mol

d. Based on the number of moles of malachite that you started with, how many grams of CO₂were produced? The molar mass of CO₂ is 44.01 g/mol. Choose the closest answer.

1.991 g 0.4401 g 0.04523 g 3.981 g

Q2a. Based on the number of grams of CO₂ and H₂O produced during the reaction, does this compensate for the observed loss of mass?

A. No, because this violates the law of conservation of mass

B. yes, this compensates for the mass lost in the reaction

C. No, because more copper oxide was produced

D. No because mass is conserved

b. You observed that the products in the crucible weigh less than the reactants that you added. How is this possible?

A. Mass was lost due to experimental error

B. The Malachite absorbed CO2 from the air

C. CO2 and H2O were released as gases

D. Mass was converted to energy

c. What kind of a reaction took place upon heating?

A. decomposition

B. single displacement

C. synthesis

D. Double displacement

d. Baking soda is used as a leavening agent in baking. When heated, baking soda undergoes a decomposition reaction to form carbon dioxide. Given the data below, which of the following reactions occurs during baking? The molar mass of baking soda is 84.007 g/mol and the molar mass of carbon dioxide is 44.01 g/mol.

Mass of empty crucible (g) = 55.000

mass of crucible with baking soda (g) = 57.000

mass of crucible and contents after the reaction (g) =56.260

A. 2NaHCO3= 2Na+2CO2 +H2O

B. 2NaHCO3 = Na2O + 2CO2 +H2O

C. NaHCO3 = NaOH +CO2

D. 2NaHCO3 = Na2CO3 + CO2 +H2O

please help me with this lab.

Ethanol Production

(Thermal Energy Conservation)

Lab Objective

Through this lab exercise, the principle of conservation of charge will be demonstrated using an adopted problem-solving methodology and a simple Matlab exercise.

Materials

Matlab 2007 or higher

Lab Assignment

Introduction

GASBUGS INC. is actually a division of a much larger alternate, fuel-generating corporation known as BIOFUELS INTERNATIONAL. One thing this company produces is ethanol (C₂H₆O) from an industrial process that uses a type of yeast (Saccharomyces cerevisiae). The elemental formula of S. cerevisiae is CH_1.83 O_0.56 N_0.17 and it has a heat of combustion of approximately -21.2 kJ/g. In their batch process, .25lb_mNH₃ and 5.0lb_m glucose are combined with the yeast at 25^oC. After the reaction goes to completion (at least one of the starting reactants is used up), 1. 4 lb_m of ethanol is produced. The unbalanced reaction for this process is:

C₂H₆O (s) + NH₃ (g) â C₃H₈O₃ (l) + C₂H₆O (l) + CH_1.83 O_0.56 N_{0.17 +} CO₂(g) + H₂O (l)

Note: 1 mol of glucose produces .5 mole glycerol (C₃H₈O₃₎ and that the ration of NH₃ to H₂O is 1:1.

You are told that it is likely that too much glucose is being added in the batch reactor process. It is your goal as the production engineering support specialist working for BIOFUELS INTERNATIONAL to model this scenario to determine how much unnecessary glucose is being added to reduce waste and cost.

Procedure

Follow the 4 steps of methodology for solving problems on pp. 44â46 of your textbook to set up the model.

Using MATLAB, create a plot that demonstrates the impact on ethanol production as the amount of glucose in the reactor varies from 1.0 lb_m to 10 lb_m.

Questions

How much excess glucose was being added to the reactor?

What is the ideal amount needed?

How much heat was produced and subsequently removed from the system?

Interpret the Matlab plot produced.

1.8 Methodology for Solving Engineering Problems. page 44-46. four steps.

Developing a pattern or methodology for solving engineering problems is important for consistency and thoroughness. The application of accounting and/conservation equations (discussed in Chapters 2â6) should be carried out in an organized manner; this makes the solution easy to follow, check, and be used by others. As a new engineer, you may find going through these many steps tedious and excessive for seemingly simple problems. However, when the level of difficulty increases, having a method or process to fall back on will be invaluable. Experienced engineers use most of the steps below when solving real-world problems.

The methodology laid out here or one similar to it should be used to solve problems throughout your career. The method outlined below is a general guide of the steps that will be followed to solve problems in Chapters 3â6 of this book, and as in real-world problems, only steps applicable to the problem should be performed. Other methodologies for solving problems are also valid; the critical issue is that you develop a thorough method and implement it regularly. As you mature as an engineer, it is appropriate that you develop your own problem-solving method.

1. Assemble. Information regarding the problem, including a picture, should be assembled and rewritten.

(a) The objective of the problem or the answer that you are seeking to findshould be clearly stated. This is often written as: Find: the flow rate ...

(b) Draw a diagram showing all relevant information. Often a simple box diagram showing all components entering and leaving the system allows information to be summarized in a convenient way. The system, surroundings, and system boundary should be drawn and labeled. When possible, all known quantitative information should be shown on the diagram.

(c) Set up a calculation table. The known values on your diagram, the components entering and leaving the system, form the foundation for the table. Units should be consistent across the table. The unknown components on the table (blanks) are often the desired answers. As you solve for different components, you can fill in the table. (Developing a table is optional, although useful, especially in multicomponent mass balance problems)

2. Analyze. A framework for understanding what is known and what is not known is developed at this stage.

(a) State any assumptions applied to the problem. Biological systems are extremely complex, since many processes and reactions, as well as transport of materials, are often going on simultaneously. Knowing when and where to make assumptions to simplify the system to a few salient features is the mark of an outstanding engineer. An example of an assumption is that the human forearm can be modeled as a cylinder.

(b) Collect and state any extra data. In this step, you may need to research information about a component in your system that was not given in the problem definition. An example of extra data that you may need to look up is the viscosity of plasma.

(c) List the variables and notations (symbols) adapted for the problem, and select a set of units for the problem. Typically, a choice is made to use either metric or British units throughout the problem.

[Note: The notations for variables may vary from discipline to discipline, but standard variables that are inherently understood within a subject do not always need to be listed. For example, kinetic energy is defined as EKin physics, but as T in mechanics. If you are calculating data that will be shared with coworkers of the same discipline, it is not necessary to define standard variables. Rather, variables specific to an aspect of the problem need to be defined (e.g., Fs = force of the astronaut on a chair).]

(d) State a basis of calculation. A basis is a specified input or output to a system (usually given as a flow rate or amount). In some problem statements, the basis is given. In other problems, values of components are given relative to one another and not as absolute amounts or rates. Select a basis if one is not given. Mass (Chapter 3) and energy (Chapter 4) problems often need a basis.

(e) If the problem involves chemical reaction(s), list the compounds involved and stoichiometrically balance the equation(s).

3. Calculate. Equations are developed and solved in a logical manner.

(a) Write down all appropriate accounting and/or conservation equations.Writing down the governing equations and then simplifying them by analyzing the system to eliminate unnecessary terms can be a helpful tool in solving engineering problems. For example, if asking the question, âIs this system at steady-state?â results in a positive response, the governing equation may be simplified by making the Accumulation term equal zero. This concept will be discussed further in Chapter 2. Write down any other essential equations needed to solve the problem.

(b) By applying the appropriate equations, calculate the unknown quantities. This is the heart of solving the problem and may require extensive effort. In some cases, the calculation of unknown quantities can be done sequentially. In other cases, it may be best to solve a series of equations using MATLAB or other computer software.

[Note: For a multi-unit or complex mass and energy conservation problems, a strategy to solve the problem may be required. A degree-of-freedom analysis is a systematic method to demonstrate whether a problem can be solved with the stated information and can help determine the sequence in which the equations should be solved. This process is discussed in chemical engineering textbooks (e.g., Reklaitis, Introduction to Material and Energy Balances, 1983).]

4. Finalize. Correct answers to the problem statement are stated clearly.

(a) State the answers clearly with appropriate significant figures and units. Confirm that you answered the specific questions asked by the problem

Laboratory Report Cover Sheet
DeVry University
College of Engineering and Information Sciences

Course Number: ECET301

Professor:

Laboratory Number: 3

Laboratory Title: Ethanol Production

Submittal Date: Click here to enter a date.

Write a brief technical lab report summarizing the technical facts learned from this lab. The report should be organized to provide the following:

Section 1âIntroduction: An introductory/summary paragraph describing the type of conservation principle being analyzed and the key elements that will be discussed relating to this principle.

Section 2âModel: The documented model using the standard problem-solving methodology in section 1.8 of your text.

Section 3âPlot: Matlab plot with script to generate.

Section 4âDiscussion: A section describing the most important characteristics shown, or demonstrate via the modeled and collected data. Also include a practical example of how the information learned in this assignment might help you in a job setting in the real world.

Section 5âConcluding Remarks: A summary statement listing the most positive aspects of the assignment and any difficulties encountered.

Please answer the question neatly and clearly.

Be as detailed as possible. Show examples if necessary. Thanks*

Lab B4 Le ChÃ¢telier's Principle Introduction All chemical reactions proceed until equilibrium is reached, provided none of the reactants or the products are removed from the reaction mixture. Le ChÃ¢telier's principle describes what happens to an equilibrium after it has been disturbed (Ebbing/Gammon, Sections 14.7, 14.8, and 14.9). 05 Purpose You will study the application of Le ChÃ¢telier's principle by seeing the effect of the addition of Fe and SCN-to an equilibrium mixture of Fe", SCN, and Fe(SCN)ê³¼, the effect of the addition of an acid to an equilibrium mixture of Ni2, NHs, and Ni(NH)% the effect of the addition of an acid and a base on the equilibrium involving an indicator; the effect of acids and bases on the solubility of Ca(OH)2 in water and the effect of temperature on an equilibrium mixture of Co', cr, and CoCla 2- New Substances In this experiment you will encounter some substances that you may not have seen before. The reaction between Fe and SCN (thiocyanate ion) gives Fe(SCN)2. This substance is a deeply colored complex ion. Other complex ions that you will encounter are Ni(NHs)6 and CoCl These substances result from the reaction between Ni? and NH3 and from the reaction between Co and CI, respectively. You will also study an equilibrium involving methyl orange, an indicator. Indicators are discussed in Appendix D. Read the second, third, and fourth paragraphs of that appendix to gain an understanding of the physical and chemical properties of this indicator. Concept of the Experiment Le ChÃ¢telier's principle can be described in the following way: "When a system in chemical equilibrium is disturbed by a change of temperature, pressure, or concentration, the system shifts in equilibrium composition in a way that tends to counteract this change of variable" (Ebbing/Gammon, Section 14.7). This statement explains the effects that you will encounter in this experiment. Procedure lib Getting Started 1. Obtain 3 small test tubes and a piece of filter paper Obtain directions for discarding the solutions that you will use in this experiment from your laboratory instructor. Be careful handling the solutions used in this experiment. 2. 3. CAUTION: Solutions of ammonia, hydrochloric acid, and sodium hydroxide can cause chemical burns, in addition to ruining your clothing. Do not use your finger as a stopper when mixing these solutions. If you spill any of these solutions on you, wash the contaminated area thoroughly and immediately report the incident to your laboratory instructor. You may require further treatment. May not be scanned, copied or duplicated, or posted to a publily accessible website, in whole or in part be o 2013 Cengage Leaming All Rights Reserved. custom page 125

CHE 2B- Final Exam Guide - Comprehensive Notes for the exam ( 25 pages long!)

CHE 2B Full Course Notes

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