Chem Chap 2 Flashcards
What is chemistry?
Study of matter and changes it undergoes
What is physics?
Study of motion, matter and energy interactions
What is a Atom?
- building block of matter
- atoms are the smallest particle of an element that can enter into a chemical reaction
- Composed of protons, neutrons, electrons
Chemical Properties
Characteristics that describe the chemical reactivity of a substance. Chemical reactions result formation of different compounds
Physical properties
Do not describe the chemical reactivity of a substance. A substance can display properties without a change in composition
The atomic number
- The number of protons in the nucleus
- determines the identity of the atom
The mass number
- the sum of proton number (or atomic number) and the neutrons
What is the Atomic mass/ Atomic weight
average mass of an atom in a natural sample of the element
Isotope
- atoms with the same atomic number but with different atomic weights
- structural variations of an atom
- have the same number of protons (and electrons) but a different number of neutrons
Radioisotopes
- heavier, unstable isotopes of an element that spontaneously decompose into more stable forms
- half life- time required to lose 1/2 of radioactivity
What is Daltons Theory
- proposes three hypothesis to explain laws of conservation of mass and definite proportions
Daltons first theory
- each element is composed of tiny, indivisible particles called atoms, which are identical for the element but are different (particularly their masses and chemical properties) from atoms of other elements
Daltons Second theory
- Chemical combination is simply the bonding of a definite, small whole number of atoms of each of the combining elements in a fixed ratio to make one molecule of the formed compound. A given compound always has the same relative numbers and types of atoms
Daltons Third theory
- no atoms are gained, lost, or changed in identity during a chemical reaction; they are just rearranged to produce new substances
Law of conservation of mass
no detectable change in the total mass occurs during a chemical reaction. This law was proposed by Antoine Lavoisier
Law of Definite proportions
different samples of pure compound always content the same elements in the same proportionably mass
- water always contains 11.2% hydrogen and 88.8% oxygen
Who was Dmitri Mendeleev
- Russian who constructed the periodic table of elements, emphasizing that chemical and physical properties are repeated in a predictable way
Rows on periodic table are called _____?
periods
Columns are called ___?
Groups or families
(elements within a family have similar chemical and physical properties)
What is periodic law
properties of elements are periodic functions of their atomic numbers
What is a covalent bond
- molecule is a group of atoms chemically bonded together into a discrete unit
- Sharing electrons
- Covalent = Close on the periodic table (generally rule formed by elements on the right side of periodic table)
What are ionic compounds
compounds that are held together by ionic bonds or the attraction or oppositely charged ions
- in solid states ionic compound form crystalline lattices
- cations are attracted to all the neighboring anions not just one
- there are no discrete ionic “molecules”
- transfer of electron
Chemical Bonds
- an energy relationship between the electrons of the reacting atoms
- bonds are formed using the electrons outermost energy level (valence shell)
Valence Shell
- outermost energy level containing chemically active electrons
Octet Rule (rule of 8)
except of the first shell which is full with two electrons, atoms interact in a manner to have eight electrons in their valence shell
Chemically Inert elements
have their outermost energy level fully occupied by electrons
Chemically Reactive elements
elements that do not have either outermost energy level fully occupied by electrons
Types of chemical bond
- ionic
- covalent
- hydrogen
Ionic Bonds
- chemical bonds that form between two atoms that transfer one or more electrons from one atom to other
- ions are charged particles
Anion
electron acceptor carrying a net negative charge due to the extra electron
- formed by gain of electrons
- nonmetals tend to form anions
- electron acceptor
Cation
electron donor carrying a net positive charge due to the loss of an electron
- formed by loss of electron
- metals tend to form cations
Crystals
large structures of cations and anions held together by ionic bonds
Ex NaCl
Nonpolar molecules
- equal sharing of electrons
- no poles
- ex CO2
- charge is balanced
Polar molecules
- unequal sharing of electrons
- creates a charged particle
- ex H2O
Hydrogen bonds
weak attractions that form between partially charged atoms found in polar molecule
- common in dipoles (water)
- responsible for surface tension
- important as intramolecular bonds giving the molecule a three dimension shape
- hydrogen bonds tend to collapse the lung
Ions
- atom or group of atoms with a charge
- cannot cross the cell membrane
Molecular compounds
made of discrete units (molecules) and usually consist of a small number of nonmetals atoms held together by covalent bonds
Hydrates
- some ionic compounds incorporate a fixed number of water molecules into their formula unit
Desiccants
- the anhydrous form of a compound that has a strong tendency to form a hydrate and is used to scavenge the last traces of water from a system
- most commonly used is silica gel (SiO2)
- addition of water to a desiccant is a reversible process so saturated desiccants can be used as moisturizers
Moles
- amount of substance that contains exactly as many particles at 12.00 grams of carbon
- this number is called Avogadros number (6.02x10^23)
- particles can be molecules, atoms, ions or electrons
- molecular mass is the sum of the masses of the component atoms
Avogrados number
6.02x10 ^23
water always contains ___% hydrogen
11.2%
water always contains ____% oxygen
88.8%
What are the big 4 elements? What percentage do they make up in our body?
- oxygen
- carbon
- Hydrogen
- Nitrogen
- 96.1 %
Ph is controlled by what element?
Hydrogen
Fe++ (ferrous) vs Fe+++ (Ferric)
- Ferrous is good
- Ferric is bad form because it decreases the hemoglobin affinity for oxygen
What clotting factor is calcium involved in?
Factor IV
what percentage of the air does Nitrogen make up?
80%
What percentage of Oxygen makes up the air?
20%
What is the most abundant intracellular ion?
Potassium
What is the most abundant extracellular ion?
Sodium
How do you calculate molecular mass?
the sum of the masses of the component atoms
Compare and contrast mixtures and compounds
No chemical bonding takes place in mixtures, most can be separated by physical means, and mixtures can be heterogeneous or homogeneous.
-Compounds cannot be separated by physical means and all compounds are homogeneous.
What are the 4 major elements in the body and their percentage? Functions?
Oxygen-65% it is needed for cellular energy (ATP)
Carbon-18.5% a primary component of all organic molecules
Hydrogen-9.5% a component of all organic molecules, as a proton it influences the pH of body fluids.
Nitrogen-3.2% a component of proteins and nucleic acids (genetic material).
What are the 9 lesser elements in the body and their percentage? Functions?
-Calcium-1.5% found as salt in bones and teeth, its ion form is required for muscle contraction, conduction of nerve impulses, and blood clotting.
-Phosphorus-1.0% part of calcium phosphate in teeth and bones, also present in nucleic acids and part of ATP.
-Potassium-0.4% most abundant ICF cation, required for conduction of nerve impulses and muscle contraction.
-Sulfur-0.3% component of proteins, particularly muscle proteins.
-Sodium-0.2% most abundant ECF cation, required for water balance, conduction of nerve impulses, and muscle contraction.
-Chlorine-0.2% most abundant ECF anion.
-Magnesium-0.1% present in bone, important cofactor in metabolic reactions.
-Iodine-0.1% needed to make thyroid hormones
-Iron-0.1% component of hbg and some enzymes
What is methemoglobinemia? Treatment?
When ferrous (good form) is converted to ferric (bad form) it causes inability for O2 to be transported, pt will become hypoxic. Give IV methylene blue. Can be caused by some local anesthetics
Role of surfactant in body?
Surfactant decreases surface tension in lungs for expansion during inhalation and prevents alveolar collapse during exhalation. Surfactant acts as a soap or detergent and breaks hydrogen bonds in lungs.
