Question 1: Draw the Lewis Dot structure of CO2 and H2O. Analyze bond angles and
bonding pairs. Which of these molecule(s) is polar? Why is there a difference in bonding
angles between water and carbon dioxide?
CO2- Bond angles are 180 degrees. There is a double bond between each oxygen and
carbon. The carbon is sp hybridized and oxygens are sp2 hybridized.
H2O- Bond angles are less than 109.5 degrees (103.9 as analyzed with chime on the class
website) which is expected from this molecule’s hybridization. The oxygens are sp3
hybridized. This molecule is polar (see above picture).
Question 2: Draw the Lewis-Kekule structure of NH3 and N2.
The nitrogen in ammonia has single bonds to each hydrogen and a lone pair. Dinitrogen
(N2) has a triple bond between the nitrogen molecules and a lone pair on each atom.
Question 3: Draw the structure of acetic acid and name the main structural property of
carboxylic acids.
Acetic Acid (don’t forget the lone pairs on the oxygen, 2 on each)
Properties of carboxylic acids include R-COOH general structure. Notice that there is
always one double bonded oxygen and one hydroxyl group.
Question 4: The gas from the hydrothermal vents is hot before the seawater cools it.
What does this say about the energy of and the molecules released by the vents? Based
on this and the article, would you say the first reactions to proceed to life were
endothermic or exothermic?
The molecules released by the vents are high in energy. This means that the first
reactions that proceeded life must have been endothermic because they took the energy
away from the water that surrounded them.
Question 5: What is the iron sulfur theory and what is the purpose of catalysts in
reactions?
(from article) "the iron sulfur world theory," because he believes that metallic surfaces, particularly those
in iron sulfide, "would have been promising facilitators or catalysts that created the precursor chemicals of
living cells"
The purpose of catalysts is to lower the activation energy of the reaction. This means that
there needs to be less energy present for the reaction to move forward and create the
products.
Question 6: Draw the structure of pyruvic acid. Give the chemical formula and the
common name of the molecule added to create alanine from pyruvic acid. (HINT: See
Insert Above)
Pyruvic Acid
NH3 common name “ammonia” is added to pyruvic acid to create alanine.