6.3 POGIL- properties of water
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1
6.3 POGIL- MODEL 1
1-How many hydrogen atoms are in a molecule of water?
-1 -2
-3
2-How many oxygen atoms are in a molecule of water?
-1 -2
-3
3- What holds the hydrogen atoms to the oxygen atom?
-hydrogen bond -covalent bond
-ionic bond
6.3 POGIL-
4-The shading around the molecule represents the relative density of
electrons shared by the atoms.
What does this indicate about the density of electrons around the
oxygen atom as compared to the density of electrons around the
hydrogen atoms?
-electrons more dense around oxygen atom than around hydrogen atom
-LABEL the water molecule’s positive and negative charge
6.3 POGIL-
5-DETERMINE where is the majority of negative charge on the water
molecule?
-oxygen
-EXPLAIN why there are more e- around oxygen.
-oxygen atomic # 8 / 6 valence electrons
-hydrogen atomic #1 / 1 valence electron
6.3 POGIL- [6.3 RDG]
-LIST: 4 Properties of water
-universal solvent
-adhesive
-cohesive
-polar
6.3 POGIL- MODEL 2-Attraction of Water Molecules
6-Looking at your answers to question 1 and 2 from Model 1, tell what
atoms are represented by:
-The small un-shaded circles in Model 2 hydrogen
-The larger gray shaded circles in Model 2 oxygen
7-What do the solid lines between the small and large circles represent?
covalent bonds
8-According to Model 2, what is represented by the dotted lines?
weak attraction – H bond
6.3 POGIL- MODEL 2-Attraction of Water Molecules
9-Remember that electrons in a water molecule are more dense around
the oxygen atom and less dense around the hydrogen atoms.
a-What kind of charge would the oxygen atom have compared to the
(-) NEGATIVE
hydrogen atoms? ___________
b-What kind of charge would the hydrogen atom have compared to
(+) POSITIVE
the oxygen atoms? ___________
10-DESCRIBE the arrangement of the water molecules in Model 2 with
one another. H atom is ATTRACTED to
O atom of water molecule
6.3 POGIL- MODEL 2-Attraction of Water Molecules
11-DESCRIBE the cause of the attractions between molecules of water.
-opposite charges attract
6.3 POGIL- MODEL 2-Attraction of Water Molecules
12-If another water molecule was added to the group in Model 2 at the
upper right side, which of its atoms would be connected to the existing
molecule with a dotted line?
DRAW the molecule and bond.
EXPLAIN your group’s reasoning:
H + charge in new molecule is attracted to
O – charge in existing molecule
6.3 POGIL- MODEL 2-Attraction of Water Molecules
13-DRAW 10 water molecules below to create a cluster.
-INDICATE the hydrogen bonds that link the water molecules.
6.3 POGIL- MODEL 2-Attraction of Water Molecules
14-Some examples of nonpolar molecules include fats, oils, and waxes.
DETERMINE how do these substances interact with water?
-they don’t interact with water
-they separate w/o intermixing with water
15-What prediction would you make about why oil and water interact in
the way described above?
-water molecules attracted to other water molecules
-NOT attracted to oil / push oil out as pack tightly together
6.3 POGIL- MODEL 3-Model of DNA Molecule
16-Other polar molecules include nucleic acids and some proteins. Look
at the DNA sketch provided and predict how the two strands are
attracted to one another.
-one strand slightly positive area
-one strand slightly negative area
17-Some molecules that are covalently bonded do not have a difference
in charge across the molecule. These molecules are referred to as
nonpolar. What arrangement of electrons would result in a nonpolar
molecule?
-even distribution of electrons
6.3 POGIL- MODEL 3-Model of DNA Molecule
16-Other polar molecules include nucleic acids and some proteins. Look
at the DNA sketch provided and predict how the two strands are
attracted to one another.
-one strand slightly positive area
-one strand slightly negative area
17-Some molecules that are covalently bonded do not have a difference
in charge across the molecule. These molecules are referred to as
nonpolar. What arrangement of electrons would result in a nonpolar
molecule?
-even distribution of electrons