Lecture Human anatomy and physiology - Chapter 2: Chemistry comes alive (part a)
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Part A
Chemistry Comes Alive
Anything that has mass and occupies space
States of matter:
1.
Solid—definite shape and volume
2. Liquid—definite volume, changeable shape
3. Gas—changeable shape and volume
Capacity to do work or put matter into motion
Types of energy:
◦Kinetic—energy in action
◦Potential—stored (inactive) energy
PLAY
Animation: Energy Concepts
Chemical energy—stored in bonds of chemical
substances
Electrical energy—results from movement of
charged particles
Mechanical energy—directly involved in moving
matter
Radiant or electromagnetic energy—exhibits
wavelike properties (i.e., visible light, ultraviolet
light, and Xrays)
Energy can neither be created nor destroyed
(1st law of thermodynamics)
Energy may be converted from one form to
another
Conversion is inefficient because some energy is
“lost” as heat
Elements
◦Cannot be broken down by ordinary chemical means
◦Each has unique properties:
Physical properties
Are detectable with our senses, or are measurable
Chemical properties
How atoms interact (bond) with one another
Atoms
◦Unique building blocks for each element
Atomic symbol: one or twoletter chemical
shorthand for each element
Eg: Copper Cu Sulfur S
Iron Fe Potassium K
Mercury Hg Phosphorus P
Gold Au Iodine I
Oxygen (O)
Carbon (C)
Hydrogen (H)
Nitrogen (N)
About 96% of body mass
About 3.9% of body mass:
◦calcium (Ca), phosphorus (P), potassium (K),
sulfur (S), sodium (Na), chlorine (Cl),
magnesium (Mg), iodine (I), and iron (Fe)
< 0.01% of body mass:
◦Part of enzymes, e.g., chromium (Cr), manganese (Mn),
and zinc (Zn)
Determined by numbers of subatomic particles
Nucleus consists of neutrons and protons
Neutrons
No charge
Mass = 1 atomic mass unit (amu)
Protons
Positive charge
Mass = 1 amu
Electrons
◦Orbit nucleus
◦Equal in number to protons in atom
◦Negative charge
◦1/2000 the mass of a proton (0 amu) Not considered in
the calculation of atomic weight
Planetary model
◦Depicts fixed circular electron paths
◦Useful for illustrations (as in the text)
Nucleus
Nucleus
Helium atom
Helium atom
2 protons (p+)
2 neutrons (n0)
2 electrons (e–)
2 protons (p+)
2 neutrons (n0)
2 electrons (e–)
(a) Planetary model
Proton
Copyright © 2010 Pearson Education, Inc.
Neutron
(b) Orbital model
Electron
Electron
cloud
Figure 2.1
Atoms of different elements contain different
numbers of subatomic particles
◦Compare hydrogen, helium and lithium (next slide)
Proton
Neutron
Electron
Hydrogen (H)
(1p+; 0n0; 1e–)
Copyright © 2010 Pearson Education, Inc.
Helium (He)
(2p+; 2n0; 2e–)
Lithium (Li)
(3p+; 4n0; 3e–)
Figure 2.2
Atomic number = number of protons in
nucleus
Atomic weight = mass of the protons and
neutrons
Proton
Neutron
Electron
Hydrogen (1H)
(1p+; 0n0; 1e–)
Copyright © 2010 Pearson Education, Inc.
Deuterium (2H)
(1p+; 1n0; 1e–)
Tritium (3H)
(1p+; 2n0; 1e–)
Figure 2.3
Spontaneous decay (radioactivity)
Similar chemistry to stable isotopes
Can be detected with scanners
Valuable tools for biological research and
medicine
Cause damage to living tissue:
◦ Useful against localized cancers
◦ Radon from uranium decay causes lung cancer
Most atoms combine chemically with other atoms
to form molecules and compounds
◦Molecule—two or more atoms of same element bonded
together (e.g., H + H = H2 )
◦Compound—two or more atoms of different elements
bonded together (e.g., C6H12O6)
Most matter exists as mixtures
◦Two or more components physically intermixed
Three types of mixtures
◦Solutions
◦Colloids
◦Suspensions
Solutions are homogeneous mixtures
Usually transparent, e.g., atmospheric air or
seawater
◦Solvent
Present in greatest amount, usually a liquid
◦Solute(s)
Present in smaller amounts
