Ch. 2 Questions

1
Ch. 2 Questions

• I can easily give you the standard written
  answers using power point. I am going to have to
  cover the drawings and illustrations a different
  way.
• You do not have to write down what is in red for
  an answer. It is me thinking out loud.

2
Concept Check 2.1 Question 1

• We are able to eat the compound because it has
  different properties from that of a metal and a
  poisonous gas.
• Remember, we are curious, we want to know the
  properties that led to what we are looking at and
  how it works. Also, how did we get to this point?
  In other words, we just dont look at the car
  engine as a whole, we are going to break the
  engine down into its individual parts and study
  them. Then we will understand the engine better.

3
Concept Check 2.1 Question 2

• Yes
• An organism requires trace elements, even in
  small amounts, otherwise it would have issues.
• Trick question. We think of the essential
  elements as the major elements, H, O, N, C, K,
  Ca, P, S. But we still need those trace elements
  to be normal, hence, they are essential.

4
Concept Check 2.1 Question 3

• A person with an iron deficiency will probably
  show fatigue and other effects of a low oxygen
  level in the blood.
• Anemia
• Iron is a red blood cell hemoglobin component
  that carries oxygen to our cells. If we are short
  on iron, we are short on hemoglobin. If we are
  short on hemoglobin, we cant carry as much
  oxygen. If we cant carry as much oxygen, we are
  tired.

5
Concept Check 2.1 Question 4

• Variant ancestral plants that could tolerate the
  toxic elements and could grow and reproduce in
  serpentine soils.
• The offspring of the variants would also vary,
  with those most capable of thriving under
  serpentine conditions growing best and
  reproducing most.
• Over many generations, this led to the serpentine
  species we see today.
• Survival of the fittest. Those that survive pass
  on the genes to survive in that environment.

6
Concept Check 2.2 Question 1

• 7
• I rounded it to the nearest whole number.

7
Concept Check 2.2 Question 2

• 15
• N
• 7

8
Concept Check 2.2 Question 3

• 9 electrons
• 2 electron shells
• 1s (1st shell), 2s, 2px, 2py, 2pz (2nd shell)
• 1 electron is needed to fill the valence shell
• If it picks up one more electron, the 2nd shell
  (Valence outer shell) would be full.

9
Concept Check 2.2 Question 4

• The elements in a row all have the same number of
  electron shells.
• In a colomn, all the elements have the same
  number of electrons in their valence shells.
• Look at the periodic table and look at the rows
  and columns. You will notice why they set it up
  this way.

10
Concept Check 2.3 Question 1

• Each C atom has only 3 covalent bonds instead of
  the required 4

11
Concept Check 2.3 Question 2

• The attraction between oppositely charged ions,
  forming ionic bonds
• This is an ionic bond

12
Concept Check 2.3 Question 3

• If you could synthesize molecules that mimic
  these shapes, you might be able to treat diseases
  or conditions caused by the inability of affected
  individuals to synthesize such molecules.
• This sounds like computer gaming to me. You video
  game junkies could work with computer 3D models
  and work with that and help develop new
  chemotherapy drugs.

13
Concept Check 2.4 Question 1

• H H
• H H O O
• 2H2 O2
• I cant draw this on power point.

14
Concept Check 2.4 Question 2

• At equalibrium, the forward and reverse reactions
  occur at the same rate.
• Hence the name EQUALibrium

15
Concept Check 2.4 Question 3

• C6H12O6 6 O2 ? 6 CO2 6 H2O energy
• Glucose and oxygen react to form carbon dioxide
  and water and energy
• We breathe in oxygen because we need it for the
  reaction to occur
• We breathe out carbon dioxide because it is a
  byproduct of the reaction

16
In what way does the need for iodine or iron in
your diet differ from your need for calcium or
phosphorous?

• Iodine is needed for a thyroid hormone
• Iron is needed for hemoglobin.
• Both of the above are trace elements and are
  needed in only minute portions.
• Calcium and phosphorous are found in bones and
  teeth and are needed in greater quantities

17
Draw the electron shells for neon and argon. Why
are these elements chemically unreactive?

• They have complete valence shells
• I think you can draw these. They have full shells.

18
In terms of electron sharing between atoms,
compare nonpolar covalent bonds, polar covalent
bonds, and the formation of ions.

• Electrons are shared equally
• An equal tug of war
• Electrons are shared unequally
• A tug of war where a bigger atom wins
• A bigger atom is more electronegative
• Electrons are transferred
• Gained or lost and can involve more than one

19
What would happen to the concentration of
products if more reactants were added to a
reaction that was in chemical equalibrium?

• The concentration of products would increase
  because the reactants would produce more
  products.
• If there is more on the left, it would proceed to
  the right.
• Continued on next slide

20
How would this addition affect the equalibrium?

• More products would only be made until an
  equalibrium is reached, again, then the forward
  and reverse reactions would occur at the same
  rate.
• Remember, diffusion never stops either. Stuff is
  always moving, unless it is absolute zero.

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The next section is..

• Ch. 2 Test your understanding

22
Question 1

• A
• Easy question

23
Question 2

• E
• Change the number of protons, then it isnt P
  anymore. Change the numbers of electrons, then it
  is an ion. Isotopes deal with varying neutrons.

24
Question 3

• B
• Atoms would like to have a full outer shell. That
  is why chemical bonding involves e-.

25
Question 4

• A
• Anions are negative ions. You would need more
  negative particles than positive particles, so
  you need more electrons than protons.

26
Question 5

• D
• Easy question

27
Question 6

• B
• If it is oxygen, it has to have 8 protons. If the
  atomic mass number is 18 then it tells me I have
  10 neutrons (18-810). If there is 8 protons an
  electrically neutral atom would have an equal
  number of e-, 8 of them. So I am thinking 8p,
  10n, 8e

28
Question 7

• C
• Sulfer has 16 protons, 2 in the first shell, 8 in
  the second shell, 6 in the third shell. If I get
  two more it would satisfy the octet rule. I can
  get 2 e- from 2 H. Therefore H2S.

29
Question 8

• E
• Easy to do. Just have to count them out.

30
Question 9

• A. Carbon needs 4 e- not 3
• B. Good molecule.
• C. H has 1e-. It cant form bonds with 2 atoms
• D. O is incomplete. H does not have a double
  bond. N needs three not 4.

31
Question 10

• You need to write what you think.

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Question 11

• Think about this question. I will ask you in
  class about it. How would you make up an
  experiment to test it?
• Better be able to use these
• What is your hypothesis?
• What is your prediction?
• How will you test it?
• What are the variables?
• What is the control group?

33
Question 12

• Make it short and sweet. I might call on you in
  class to read your essay aloud. I am not worried
  about the length of the essay. I want quality!
  Now argue with the guy that said that and set him
  straight.