Transcript Properties of Water

Properties of Water
Sara Burnham
Biology HHS
Types of Bonds
• Ionic bond – one or more electrons
transferred from one atom to another
• Covalent bond – shared electrons; single,
double, or triple bond
• Van der Waals – slight attraction between
oppositely charged regions of nearby
molecules
Water is Polar
• Shared electrons stay closer to oxygen than
hydrogen because oxygen has a stronger
attraction for electrons
• Oxygen on one end and hydrogen on the other
end
• Since electrons spend more time near oxygen
atom, oxygen has a slight – charge and
hydrogen has a slight + charge
• Water is polar because electrons and charge are
unevenly distributed.
Hydrogen Bonding
• Hydrogen bonding occurs between
neighboring water molecules because of
the slight charge
• Hydrogen atom of one water molecule is
attracted to the oxygen atom of a
neighboring molecule
• Creates surface tension
Surface Tension
• Water strider can “walk on water” because
of surface tension
• Cohesion creates
surface tension
• Cohesion is the
the attraction of between molecules of the
same substance.
Solution
• Mixture where water is the solvent and the
substance dissolved is the solute
• Ex: sugar in water, salt in water
Suspension
• Mixture where material does not dissolve
in water
• Ex: flour in water, mud in water
Carbon
• Important building block of life
• Base of every organic molecule
• 4 valence electrons
– Each has the ability to join with an electron
from another atom forming a strong covalent
bond
– Can bond to other carbon atoms forming
chains almost unlimited in length; single,
double, or even triple bonds can be formed
Carbohydrates
• Made up on carbon, hydrogen, and
oxygen
• Body’s main source of energy
• Can also be used for structural purpose
• Sugars
Monosaccharides
• Single sugars
• Ex: glucose, galactose, fructose
Disaccharides
• Two monosaccharides bound together
• Ex: lactose (glucose and galactose),
sucrose (glucose and fructose), and
maltose (two glucose molecules)
Polysaccharide
• Thousands of monosaccharides linked
together
• Ex: glycogen, starch cellulose
Lipids
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Made mostly of carbon and hydrogen
Not soluble in water
Consists of fats, oils, and waxes
Can be used to store energy
Many lipids are formed with glycerol and a
fatty acid tail
• Steroids are lipids
Saturated
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Lipid with only single bonds
“Saturated with hydrogens”
Solid at room temperature
Ex: animal fat (lard), fatty meats
Unsaturated
• Has at least one double bond
• Liquid at room temperature
• Ex: vegetable oil, olive oil, canola oil
Polyunsaturated
• Many double bonds (more than one can
be considered polyunsaturated)
Nucleic Acids
• Nucleotides joined covalently
• Contain carbon, hydrogen, oxygen, nitrogen,
and phosphorous
• Polymers from monomers called nucleotides
• Nucleotide has 5-carbon sugar, phosphate
group, and a nitrogenous baase
• RNA – ribose sugar; DNA – deoxyribose sugar
– Store genetic information
Proteins
• Contain carbon, nitrogen, hydrogen, and
oxygen
• Monomer of protein (polymer) is amino
acid
– Have amino group (-NH2) at one end and a
carboxyl group (-COOH) at the other end
• More than 20 different amino acids found
in nature
• When two or more amino acids are bound,
still has amino group on one end and
carboxyl group on the other end
• Polypeptide chain has three or more
amino acids bound together
• Polypeptide bond forms as a condensation
reaction (rxn) joins the amino group of one
amino acid with the carboxyl group of the
next in line  H2O released
Peptides
• Short polymers