Re: 9.4.2 Practice: Bonding Practice -Bobbie Salcedo

[Williams, Sue]

On Sun, Nov 18, 2012 at 10:45 PM, <sue.wi...@apps.cabarrus.k12.nc.us> wrote:

26 out of 50 points  Correct and resubmit

On Thursday, November 15, 2012 9:27:44 AM UTC-5, xobaby...@aol.com wrote:

9.4.2 Practice: Bonding Practice Assignment
 
 
Physical Science (S1744040) Bobbie Salcedo

1.Bonds are attractive forces that hold compounds together. What role do valence electrons play in the formation of bonds? (3 points)

Valence electrons are the electrons that are on the outter shell of the atoms..and takes part in bonding.. 3 points

2.How do ionic bonds differ from covalent bonds? (3 points) 2 points  are electrons lost, gained or shared in the bonds

Covalent bonds are bonds formed between two non-metals…when ionic bonds are formed between a metal and a non-metal…

3.What is the difference between the electronegativity values of carbon and sulfur? What type of bond do they form? How do you know? (4 points)

Carbon is 2.55 and sulfur is 2.58 and sulfur has a higher electronegativity…the bond they form is covalent bond…cause difference of electronegativities is less than 1.7 and carbon has half filled valence electronic shell.  4 points

4.What is the difference between the electronegativity values of sodium and bromine? What type of bond do they form? How do you know? (4 points)

Sodium form covalent bonds…while bromine form hydrogen bond…both of them will form ionic bonds because of the large electronegativity difference cause of the a metal and a nonmetal..

   2 points  explain the first sentence

5.What does it mean when a covalent bond is polar? How can you tell if a bond is polar or nonpolar? (4 points)

bond is shared between two atoms..You can tell by the type of elements in the compound decides  Incorrect

6.How does the octet rule influence Lewis dot structures? (4 points)

Sketch of a molecule that uses dots to represent valence electrons

  What does it state?  1 point

7.Answer the following questions based on the Lewis dot structure for water on the right. (4 points)

a. How many bonding pairs are present? How many lone pairs?

oxygen atom has 2 lone pairs of electrons around it, and each lone pair has 2 electrons in it. 1 points

b.The electron-group geometry of the water molecule is a tetrahedron, but the molecular geometry is bent. How can this be explained?

water molecule is tetrahedral even though the molecular geometry

2 points

c.Is the water molecule polar? Why, or why not?

Yes its polar because the hydrogen bonding between H & O atoms

What is the arrangement?

8.Answer the following questions based on the Lewis dot structure for carbon dioxide on the right. (4 points)

a.Why does carbon dioxide have a higher bond order than water?

Carbon Dioxide is made up of Carbon and Oxygen and them two bonds together make a stronger force over  1 point

b.What does this bond-order difference mean, in terms of bond energy?

Bond energy is when chemical bonds are formed when electrons from two atoms interact with each other and their atoms become joined, or glued, together…while bonumber of bonding pairs of electrons in a covalend order is the nt bond.  Copied  what does this mean>

9.Compare exothermic reactions and endothermic reactions. Give at least one similarity and one difference. (4 points)

Exothermic reaction is a reaction in which heat is given off…endothermic reaction is when heat has to be added in order for a reaction to occur. And they both involve an enthalpy change.

    3 points

10. Why does hydrogen bonding help ice cubes float? (4 points)

the lattice structure of the ice helps makes it less dense than liquid water..so making ice float on top of water. 4 points

11. Table salt, NaCl, is a classic binary ionic compound. (4 points)

a.        What is the oxidation number of Na? Of Cl?
4

Incorrect

b.What characteristics make NaCl a salt?

an ionic compound dissolves in water and it increases the waters ability to conduct electricity.  2 points

12. Water is the most common covalent compound on the planet. (4 points)

a. Write the molecular formula for water. What would be the correct name for this molecule, if nomenclature (chemical-naming) guidelines were followed?

Hydrogen oxide ..H2O…theres 2 hydrogen atoms..and is bonded to one oxygen atom.

 Incorrect

c.What evidence do you have that water is a covalent compound?

Because water contains hydrogen and oxygen and there are both nonmetals.  1 point

13. Iron is a transition metal with multiple oxidation numbers. (4 points)
a. What is the iron (II) ion? How does it differ from the iron (III) ion?
Fe^2 or Fe^3

b.If iron were to bond with oxygen, predict the formula for each oxidation number of iron.

FeO^2, FeO^3, FeO^4  Incorrect  see me for help

c.How would each formula be named?

By its data   Incorrect see me for help

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