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Why is water such a good solvent?
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[Water
Molecule is shown using the Jmol Applet]
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To rotate click left mouse button over the java applet
image and drag cursor. Zoom with middle button...
Try changing to CPK -- Click right mouse button
in box--->
Render -->Scheme -->CPK
Use left mouse button to rotate
[Right mouse button for more Options]
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| A
water
molecule is formed when two atoms of hydrogen bond covalently
with an atom of oxygen. In a covalent bond electrons are shared
between atoms. In water the sharing is not equal. The oxygen
atom attracts the electrons more strongly than the hydrogen.
This gives water an asymmetrical distribution of charge. Molecules
that have ends with partial negative and positive charges
are known as polar molecules. It is this polar property that
allows water to separate polar solute molecules and explains
why water can dissolve so many substances. |
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Water is a
good solvent due to its polarity. The solvent properties of water
are vital in biology, because many biochemical reactions take
place only within aqueous solutions
When
an ionic or polar compound enters water, it is surrounded by water
molecules. The relatively small size of water molecules typically
allows many water molecules to surround one molecule of solute.
The partially negative dipoles of the water are attracted to positively
charged components of the solute, and vice versa for the positive
dipoles.
An example
of an ionic solute is table salt.
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Liquid
water has a partially ordered structure in which hydrogen
bonds are constantly being formed and breaking up. |
The strong
hydrogen bonds also give water a high cohesiveness and, consequently,
surface tension. This is evident when small quantities of water
are put onto a nonsoluble surface and the water stays together
as drops.
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What is the distance
in angstroms for the hydrogen bond shown above?
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[Water
Molecule is shown using the Jmol Applet]
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To measure
distance
Label the
atoms:
Right mouse
button -->Labels --> With atom names
Double click
on hydrogen (H31) then drag to oxygen (O28) -- double click again
To measure
angles
Double click
on first atom, once on middle atom, twice on atom three.
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1)
What is the distance of the hydrogen bond show?
Please
enter your answer in the space provided:
2) What is
the measure of the HOH angle in a single molecule of water?
3)What is distance between the oxygen atoms in a water dimer?
