A+P 1.2 Basic Chemistry Flashcards
Chemistry
the science of the structure and interactions of matter
Chemical element
all matter is made up of a limited number of building blocks called chemical elements
examples of elements
H=hydrogen K=potassium
C=carbon Na=sodium
O=oxygen Fe=iron
N=nitrogen Ca=calcium
how many elements are normally present in the human body
26
Major elements of the human body
O, C, H, and N = 96%
8 lesser elements of the human body
3.6% = calcium(Ca), phosphorus(P), potasium(K), sulfur(S), sodium(Na), chlorine(Cl), magnesium(Mg), iron(Fe)
trace elements in human body
14, tiny amounts making up only .4%
Function of (I) iodine in human body
essential for thyroid to make hormones
Atoms
smallest unit of an element; consists on nucleus (protons and nutrons) and one or more electrons
Nucleus
centrally located; contains positively charged protons(p+) and uncharged (neutral) neutrons.
electrons (e-)
negatively charged particles that move about in a large space surrounding the nucleus
electron shell capacity
2 or 8
Atomic number
number of protons in the nucleus
atomic mass number
total number of protons plus neutrons
Ions
an atom that has a positive or negative charge due to unequal number of protons and electrons
Ion symbolization
chemical symbol followed by the number of its positive(+) or negative(-) charges
ex. Ca2+ = calcium with two positive charges.
Cations
Positively charged ion due to giving up electrons
Anion
negatively charged ion due to gaining electrons
Molecule
- formed when atoms SHARE electrons
- consists of 2 or more of the same or different elements
Molecular formula
indicates the number and type of atoms that make up a molecule.
Compounds
substance that contains 2 or more DIFFERENT elements
Free radical
unstable ions or molecules that can be destructive to other nearby molecules because of unpaired electrons in the outer shell. break apart body molecules by giving up unpaired electron or taking from another molecule.
*superoxide - addition of an electron to an oxygen molecule
3 general types of chemical bonds
ionic bonds, covalent bonds, hydrogen bonds
Octet rule
Biologically important atoms combine to form molecules and share electrons to form arrangements with 8 electrons in the outer shell
Ionic Bond
electron is transferred from one atom to another. Ions with opposite charges are attracted ton one another
ionic bonds in the body
mainly found in teeth, bones, and dissolved on body fluids.
Electrolytes
formed when ionic compounds break apart in solution.
critical in H2O movement, acid base balance, producing nerve impulses
Covalent bonds
- formed when atoms SHARE one, two, or three pairs of electrons.
- the greater number of shared pair of electrons, the stonger the bond
- most do not break apart when dissolved in water
Nonpolar covalent bond
share electrons equally
bonds between two identical atoms are always nonpolar covalent bonds
Polar covalent bond
- unequal sharing of electrons
* ex. H20, side with H atoms is slightly positive, while side with O atom is slightly negative
Hydrogen bond
- forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of a neighboring electronegative atom.
- results from attraction of oppositely charged parts of molecules rather than sharing of electrons.
chemical reaction
- occurs when new bonds form or old bonds break between atoms
- requires energy to form new bonds
- releases energy when breaking old bonds
- most reactions involve both breaking and forming bonds
two main forms of energy
- potential - stored energy (by position of chemical bonds)
- kinetic - energy of matter in motion
chemical energy
a form of potential energy that is stored in the bonds of molecules
Types of chemical reactions
synthesis, decomposition, exchange, reversible
Synthesis reactions
- when two or more atoms, ions, or molecules combine to form new larger molecules.
- synthesis = anabolism
A+B=AB
Decomposition reactions
- splitting molecules apart into smaller molecules, ions, or atoms
- decomposition = catabolism
AB= A & B - energy may be stored as ATP (adenosine triphosphate)
- ATP is used to power synthesis
Exchange reactions
- involve both synthesis and decomposition
- AB + CD = AD + CB
- HCl+NaHCO3 = H2CO3 + NaCl
Reversible reaction
- reactions that can go in either direction (annotated by two half arrows) under specific conditions
- conditions are written above above or below arrows
Metabolism
Sum of all chemical reactions in the body.
two main classes of chemical compounds in the body
Organic and inorganic
Inorganic Compounds
- Usually lack carbon
- held together by ionic or covalent bonds
- structurally simple
- usually acids, bases, and salts
ex. Water H2O, Carbon Dioxide CO2, Bicarbonate HCO3
inorganic acids, bases, and salts
- dissociates into ions in water
- Acids -> H+ ions
- Bases -> OH- ions
- Salts -> a cation and an anion, neither of which are H+ or OH-
Organic compounds
- always contain carbon
- usually contain hydrogen
- always have covalent bonds
organic compound examples
Carbohydrates, Lipids, Proteins, Nucleic acids, ATP (adenosine triposphate)
Water
- most important and abundant chemical in the human body (55-60%)
- Vital compound for life
- good solvent, participates in chemical reactions, absorbs and releases heat slowly, lubricates
- involved in digestion, circulation, elimination of waste, and regulating body temperature
Acid-Base Balance
- maintain homeostasis, body fluids must maintain a specific balance of acids and bases.
- the more hydrogen(H+) dissolved in fluid = more acidic
- the more hydroxide(OH-) dissolved in fluid = more basic (alkaline)
- Neutral pH of 7 has equal H+ and OH-
- a change of a whole number represents a 10 fold change in the number of H+
Buffer System
- how the body maintains pH within the limits of homeostasis
- homeostasis mechanisms maintains the pH of blood between 7.35 - 7.45
- ensures the pH of fluids inside and outside cells remain almost constant
Carbonic acid - Bicarbonate
Buffer System
- Carbonic acid(H2CO3) = weak acid
- Bicarbonate(HCO3-) = weak base
- excess of H+, HCO3- can remove the excess H+ as follows
- H+ (+) HCO3- –> H2CO3
- shortage of H+, H2CO3 will provide H+ as follows
- H2CO3 –> H+ (+) HCO3-
