1. Use the second member of each group from Group IA to Group 7A to show that the number of valence electrons on an atom of the element is the same as its group number.

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Written Assignment 9: Chemical Bonding

 

Answer all assigned questions and problems, and show all work.

 

1.      Use the second member of each group from Group IA to Group 7A to show that the number of valence electrons on an atom of the element is the same as its group number.
(8 points)

Li has 1 valence electron

Cl has 7 valence electrons

(Reference: Chang 9.2)

 

 

 

2.   Explain the following: (3 points)

a.       ionic bond=electrostatic force that holds ions together in an ionic compound.

 

b.      nonpolar covalent bond=electrons are shared equally between the two atoms.

 

c.       polar covalent bond= the electrons spend more time in the vicinity of one atom than the other.

 

 

3.      Specify which compound in the following pairs of ionic compounds has the higher lattice energy: Explain your choice. (6 points)

a.       KCl or MgO=MgO

 

b.      LiF or LiBr=LiBr

 

c.       Mg3N2 or NaCl=NaCl

(Reference: Chang 9.23)

 

 

 

 

4.      Compare the properties of ionic compounds and covalent compounds. (6 points)

 

Electronegativity is a property of atoms, not bonds. An ionic bond is formed between elements with very different electronegativities, a covalent bond between atoms with similar electronegativities.

                (Reference: Chang 9.32)

 

 

 

5.      Four atoms are arbitrarily labeled D, E, F, and G. Their electronegativities are as follows: D = 3.8, E = 3.3, F = 2.8, and G = 1.3. If the atoms of these elements form the molecules DE, DG, EG, and DF, how would you arrange these molecules in order of increasing covalent bond character?  (4 points)

DG,EG,DF,DE

(Reference: Chang 9.37)

6.     Classify the following bonds as ionic, polar covalent, or nonpolar covalent, and

give your reasons:  (4 points)

a.       the CC bond in H3CCH3- Covalent

b.      in KI the KI bond- Ionic

c.       the NB bond in H3NBCl3– Polar Covalent

d.      the CF bond in CF4– Polar Covalent

(Reference: Chang 9.39)

 

 

 

7.      Write the correct Lewis structures for the following compounds (relative positions of atoms are shown correctly). (21 points)

a.       H   C   N

b.      H   C   C   H

c.       O   Sn   O

d.      F        F

     B

     F

 

e.       H   O   F

f.       H
       C    F

O

g.      F         F

                  N

                  F

(Reference: Chang 9.47)

 

 

 

8.      Classify the following substances as ionic compounds or covalent compounds containing discrete molecules: CH4, KF, CO, SiCl4, BaCl2.(5 points)
CH4=Covalent KF=Ionic CO=Covalent SiCl4=Covalent BaCl2=Ionic

(Reference: Chang 9.73)

 

 

 

9.      Predict the geometries of the following species using the VSEPR method: (a) PCl3,
(b) CHCl3, (c) SiH4, (d)TeCl4.  (12 points)

a.       1 lp AX3E trigonal pyramidal

b.      0 lp AX4 tetrahedral

c.       0 lp AX4 regular tetrahedral

d.      1 lp AX4E a see-saw structure

            (Reference: Chang 10.7)

 

 

 

10.  Predict the geometry of the following molecules using the VSEPR method: (a) HgBr2,
(b) N2O, (c) SCN– (arrangement of atoms is SCN).  (9 points)

 

            (Reference: Chang 10.11)

a.linear

b.linear

c.linear

 

 

 

 

 

      11.  Describe the geometry around each of the three central atoms in the CH3COOH

molecule.
(5 points)

1. Tetrahedral, four bonds, 109.5 degrees apart, sp3 hybridization

2. Trigonal planar, three bonds (one double, to O), sp2 hybridization

3. Bent (at about 109.4 with two lone pairs, sp3 hybridization

            (Reference: Chang 10.13)

 

 

 

12.     What is the relationship between the dipole momentand bond moment? How is it

possible to have bond moments and yet be nonpolar? (3 points)

 

1.The dipole moment can be thought of as the sum of the bond dipoles in a molecule. If you have a molecule that consists of only one bond, then the dipole moment will be the same as the bond dipole. Most molecules have a dipole moment owing to the uneven distribution of charges about the molecule.

2.Because those molecules are symmetrical. CO2 and CCl4 are examples. the dipole moments of each bond cancel.

(Reference: Chang 10.16)

 

 

 

13.     Specify which hybrid orbitals are used by carbon atoms in the following species:

(a) CO,
(b) CO2, (c) CN–.  (6 points)

a.       sp + p + p.

b.      sp

c.       sp + p + p.

 

(Reference: Chang 10.37)

 

 

 

14.     How many sigma bonds and pi bonds are there in each of the following 

        Molecules? (6 points)

 

 

a.4 sigma bonds

 

 

b.5 sigma bonds and 1 pi bond 

 

 

c.7 sigma bonds and 3 pi bonds

(Reference: Chang 10.41)

 

 

15.  Which of the following species is not likely to have a tetrahedral shape? (a) SiBr4 (b) NF4+, (c) SF4, (d) BeCl4–2, (e) BF4–, (f) AlCl4–(6 points)

c.SF4

(Reference: Chang 10.71)

 

 

 
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equation and a problem

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  i have two chemistry questions ? 

 
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Calculate the molarity of a solution prepared by dissolving 6.80g of AgNO3 in enough water to make 2.50L of solution….

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Calculate the molarity of a solution prepared by dissolving 6.80g of AgNO3 in enough water to make 2.50L of solution.

 
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Chemistry HW – Junior -HS – 14 questions

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I have attached 2 pages…..I need questions 6-11 completed and second page, I need 12-15 questions completed.

first page 6 questions

second page 4 questions…..need in 24  hours

 
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develop and fix grammar mistaks in my statement of purpose

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I need a writer who can develop my statement of purpose and fix any grammar mistakes for PhD degree in chemistry

 
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chemistry post lab

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Two questions need to answer.

see pic

The lab name is Synthesis of a Mystery Alum

 

 
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Write a revie artile about "GALC enzyme". Focuses on how the enzyme removes the sugar and the mechanism for that…

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Biochem major writer needed.

 

 

Write a review artile about “GALC enzyme”. Focuses on how the enzyme removes the sugar and the mechanism for that and discuss why this process is important and what happens when this reaction doesn’t happen and how that leads to Krabbe disease. Talk about what would cause the enzyme to not work properly therefore leading to the disease. Talk about mutations and whether that changes the structure or folding of the enzyme which then causes the cerebroside to not be recognized anymore or the proper residue isn’t there to interact with galactose.

-Formatting requirements: use EITHER 11pt Arial OR 12pt Calibri OR 12pt Times New Roman font, 1” margin on all sides of the page, double-spaced. Include page numbers.

– Length: 8-10 pages (note maximum and minimum lengths). You can have extra pages for figures and references; however, there is a limit of 5 figures (with no more than 4 panels per figure).

- Your figures should be included at the end of the paper and not embedded in the main text (but you should reference each by figure number in the main text when you want to talk about it). - Make sure that each figure is labeled by figure number and has its own figure legend (i.e. sentences that describe what the figure is showing, what the colors mean, etc). DO NOT just copy the figure legend from the source paper!

- Your review article will be evaluated based on clarity and organization of the research concepts related to the topic you have chosen, as well as scientific content. Criteria for grading: Biochemical content (30 pts) Depth and focus (20 pts) Organization (15 pts) Writing quality and clarity (20 pts) Extras (15 pts, this includes issues relating to your references, figures, formatting, etc)

-Keep in mind a review article is not just a summary of a string of different papers! There is a story you are trying to tell, with subtopics.

–  You must write as if you want to publish the review article. This means your article must have a real TITLE and ABSTRACT (which contains a sentence that clearly articulates the scope of your review article) as well as the main content. Keep in mind that you want to discuss concepts in a self-contained manner; you should not expect the reader will look up all your references, and therefore any figures that are particularly important to your topic should be included in your paper (but choose carefully – only 5 figures are permitted). I will provide 4  primary articles, but you can choose and use as many secondary articles as you want. Secondary journal articles (or books or valid on-line sources) are those that you use to clarify an aspect of your primary journal article or to provide background information about your topic. Keep in mind you are writing your own review article, so most of your secondary references should be research articles and NOT review articles. Be careful that you do not just mimic a review article that already exists!

 
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JAVA Modifications file

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First Modifications to CWM billing.java file

 

At the end of the LM6 CWM video, you have a billing.java file that contains two computeBill methods.  One is for one photo book, the other is for multiple photo books.  Modify you programs so that does the following:

 

Open up your billing.java file and save as LM6Assignment.  After that, change your class name to LM6Assignment.

In main, create a variable called numBooks of type Int and write a statement that will ask the user to enter how many photo books they want to purchase.  Remember to include import java.util.Scanner; above your class and Scanner inputDevice = new Scanner(System.in);  in main.

In your call to computeBill that takes 2 arguments, instead of the number 4, pass it the variable numBooks such as multBooks = computeBill(onePhotoBook, numBooks);

At this point, compile and run your code.  The sample output might look something like the following:

The cost of one photo book is $11.87

 

How many Photo Books would you like to purchase: 7

 

The cost of multiple photo books is $83.08

 

Second Modifications to LM6Assignment.java file

 

 

Our next task will be to write a 3rd computeBill method that receives three parameters.  They represent the price of a photo book, the quantity ordered as entered from the user, and a coupon value.  Multiply the coupon quantity and price, reduce the result by the coupon value, and then add the 8% tax and return the total due.  Start by doing the following:

 

·                     Create a third overloaded method that also takes in coupon value such as    public static double computeBill(double amt, int quantity, double couponvalue)

 

·                     In main, create a variable called couponValue and ask the user to enter the percent of a discount in decimal format.  For example, a 15% discount would be entered as .15.  Also in main, create a double variable called multBooksWithCoupon.

 

·                     In main, make a new/third call to computeBill that takes three arguments and returns totalDue, such as:       multBooksWithCoupon = computeBill(onePhotoBook, numBooks, couponValue);

 

·                     In main, display the cost of multiple books with a coupon code.  This will not work until you write the third overloaded method.

 

Third Modification to LM6 Assignment.java file

 

We already wrote the method header for the third overloaded method that takes 3 arguments.  Now, we need to code the details.  So far, our third method should look like this:

 

   public static double computeBill(double amt, int quantity, double couponValue)   {      }

 

In the body of the method between the {  } we need to multiply the quantity and price, and then reduce the result by the coupon value, and then add the 8% tax and finally return totalDue.  The breakdown of variables declared and formulas are:

 

double totalDue = 0; //local variable     

double subTotal = 0; //local var     

double tax = 0; //local var     

double discount = 0;     

subTotal = amt * quantity;     

discount = subTotal * couponValue;     

tax = (subTotal – discount) * .08;     

totalDue = subTotal – discount + tax;      

Sample output of the program working properly:

 

Run 1:

 

The cost of one photo book is $11.87

 

How many Photo Books would you like to purchase: 12

 

What is the value of the coupon? Ex: for 15% enter .15 or for 20% enter .2:  .15

 

The cost of multiple photo books is $142.43

 

The cost of multiple photo books with a coupon is $121.07

 

Run 2:

 

The cost of one photo book is $11.87

 

How many Photo Books would you like to purchase: 7

 

What is the value of the coupon? Ex: for 15% enter .15 or for 20% enter .2:  .15

 

The cost of multiple photo books is $83.08

 

The cost of multiple photo books with a coupon is $70.62

 

What to attach?

 

Be sure to include your sample output at the bottom of your code in comments.  Attach your .java file when your program is complete, compiles, and is executable.

 

see attached for the billing syntex that MUST be used.

 
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CHEMISTRY CHAPTER 1

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Exercise 1.20: Review Questions

Part A

What is the standard SI base unit of length?

[removed]1 km

[removed]1 m

[removed]1 N

[removed]1 mm

[removed]1 hr

Part B

What is the standard SI base unit of mass?

[removed]1 in

[removed]1 m

[removed]1 kg

[removed]1 K

[removed]1 g

Part C

What is the standard SI base unit of time?

[removed]1 min

[removed]1 day

[removed]1 km

[removed]1 hr

[removed]1 s

Part D

What is the standard SI base unit of temperature?

[removed]1 K

[removed]1 s

[removed]1 ∘ F

[removed]1 kg

[removed]1 Å

Exercise 1.64: Problems by Topic – Density

A supposedly gold nugget is tested to determine its density. It is found to displace 19.3 mL of water and has a mass of 371 grams.

Part A

Could the nugget be made of gold?

[removed]yes

[removed]no

Exercise 1.71: Problems by Topic – The Reliability of a Measurement and Significant Figures

How many significant figures are in each of the following numbers?

Part A

0.0053 s

[removed]2

[removed]4

[removed]5

[removed]ambiguous

Part B

312,000 s

[removed]1

[removed]3

[removed]6

[removed]ambiguous

Part C

3.12×10 5 km

[removed]1

[removed]2

[removed]3

[removed]ambiguous

Part D

13,127 s

[removed]2

[removed]3

[removed]5

[removed]ambiguous

Part E

2000

[removed]1

[removed]2

[removed]4

[removed]ambiguous

Exercise 1.58: Problems by Topic – Units in Measurement

Express the quantity 255074 m in each of the following.

 

Part A

km

Express your answer using six significant figures.

255074 m = 

 

 

Part B

Mm

Express your answer using six significant figures.

255074 m = 

 

 

Part C

mm

Express your answer using six significant figures.

255074 m = 

 

 

Part D

cm

Express your answer using six significant figures.

255074 m = 

 

 

 

 
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An excited h atom with the electron in energy level 4 emits a photon wavelength of 97 nm. What energy…

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An excited h atom with the electron in energy level 4 emits a photon wavelength of 97 nm. What energy level does the electron drop to?

 
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