IndietroAnatomy & Physiology: Chemistry Basics
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Termini in questo insieme (29)
Matter is anything that takes up space and has mass, including organisms, rocks, and oceans.
An atom is the smallest unit of an element and matter, composed of subatomic particles.
Protons (positive charge, in nucleus), neutrons (neutral charge, in nucleus), and electrons (negative charge, orbit nucleus).
The atomic number is the number of protons in the nucleus of an atom, unique to each element.
The mass number is the total number of protons and neutrons in an atom's nucleus.
Valence electrons are electrons in the outermost energy shell of an atom, important for chemical bonding.
The octet rule states atoms are most stable when their valence shell has 8 electrons (2 for the first shell).
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
A radioactive isotope is an unstable isotope that breaks down and emits energy as rays or particles.
A chemical bond is an attractive force holding atoms together to form molecules or compounds.
Intramolecular bonds occur within a molecule; intermolecular bonds occur between molecules.
Ions are atoms or molecules with a net electrical charge due to gain or loss of electrons.
Anions are negatively charged ions (gain electrons); cations are positively charged ions (lose electrons).
An ionic bond is an electrical attraction between oppositely charged ions (cations and anions).
A covalent bond is formed by the sharing of electron pairs between atoms.
Nonpolar covalent bonds share electrons equally; polar covalent bonds share electrons unequally, creating partial charges.
Noncovalent bonds are interactions without electron sharing, including ionic bonds, hydrogen bonds, and Van der Waals forces.
A hydrogen bond is a weak interaction between a hydrogen atom covalently bonded to F, O, or N and another electronegative atom.
Water is polar because it has partial positive charges on hydrogen atoms and a partial negative charge on the oxygen atom.
Properties include cohesion, adhesion, high specific heat, high heat of vaporization, density differences between ice and liquid, and universal solvent ability.
Cohesion is water molecules sticking to each other; adhesion is water molecules sticking to other polar surfaces.
Ice is less dense than liquid water because stable hydrogen bonds form a lattice structure that spaces molecules farther apart.
Specific heat is the energy required to raise temperature; water's high specific heat helps stabilize environmental and body temperatures.
Evaporation is liquid to gas phase change; heat of vaporization is energy needed for this change, high in water due to hydrogen bonds.
Water dissolves many substances due to its polarity, forming hydration shells around solutes.
Hydrophilic substances dissolve in water (polar/charged); hydrophobic substances do not dissolve (nonpolar).
Acids increase H+ concentration; bases decrease H+ concentration in solution.
The pH scale measures H+ concentration, ranging from 0 (acidic) to 14 (basic), with 7 being neutral.
Buffers resist changes in pH by donating or accepting H+ ions to maintain stable pH in biological systems.