9 practice
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2.How do ionic bonds differ from covalent bonds? (3 points)
an ionic bond is the transfer of electrons and a covalent bond is a sharing of electrons
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)
Both Carbon and Sulphur have an electronegativity value of 2.5
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)
The difference between the electronegativity values of sodium and bromine: Sodium form covalent bonds . The other one form hydrogen bond.
5.What does it mean when a covalent bond is polar? How can you tell if a bond is polar or nonpolar? (4 points)
The reason a bond would be polar is because one atom has a higher electronegativity value
6.How does the octet rule influence Lewis dot structures? (4 points)
Lewis dot diagrams are drawn to show how many electrons are associated with any given atom, and how the atoms are shared, in the case of covalent bonding. Generally, each atom winds up with 8 electrons. Not hydrogen
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?
2 bonging pairs, 2 lone pairs
b.The electron-group geometry of the water molecule is a tetrahedron, but the molecular geometry is bent. How can this be explained?
The water molecule maintains a bent shape (bent at 107.5 degrees actually) because of two considerations. First the tetrahedral arrangment around the oxygen and Second the presence of lone pair electrons on the oxygen.
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 those bond together to make a stronger force over Hydrogen Oxide which is what water is made up of
b.What does this bond-order difference mean, in terms of bond energy?
Bond order is the number of chemical bonds between a pair of atoms
9.Compare exothermic reactions and endothermic reactions. Give at least one similarity and one difference. (4 points)
exothermic reactions release heat energy to their surroundings, whereas endothermic reactions absorb heat from their surrounding
10. Why does hydrogen bonding help ice cubes float? (4 points)
Hydrogen bonds are responsible for the lattice structure of ice, making it less dense than liquid water, thereby making ice float on top of water.
11. Table salt, NaCl, is a classic binary ionic compound. (4 points)
a. What is the oxidation number of Na? Of Cl?
+,1 -1
b. What characteristics make NaCl a salt?
When an ionic compound dissolves in water, it increases the water's ability to conduct electricity
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?
Dihydrogen monoxide.
b. What evidence do you have that water is a covalent compound?
Because when hydrogen atoms combine with the oxygen atom, they do so by sharing their outer shell electrons to gain a full outer shell.
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?
Iron (ll) has a +2, iron(lll) has +3 charge
b.If iron were to bond with oxygen, predict the formula for each oxidation number of iron.
feo2 feo3 feo4
c.How would each formula be named?
f you have Fe(II) oxide, FeO, it would be called "ferrous oxide."
If you have Fe(III) oxide, Fe2 O3, it would be called "ferric oxide."