Chapter 2 Flashcards
Anything that occupies space and has mass
Matter
A pure substance that cannot be broken down into simpler substances by ordinary chemical of physical techniques
Element
The smallest unit that retains the chemical and physical properties of an element
Atoms
An element that occurs in organisms in very small quantities. In nutrition a mineral el required by organisms only in small amounts
Trace elements
The name of a molecule written in chemical shorthand
Formula
A unit of atoms combined chemically in fixed numbers and ratios
Molecules
The part of an atom which consists of subatomic particles called protons and neutrons
Atomic nucleus
A molecule whose component atoms are different
Compounds
Uncharged subatomic particle in the nucleus of an atom
Neutrons
A subatomic particle in the nucleus of an atom that carries one unit of charge
Protons
Negatively charged particles outside the nucleus of an atom
Electrons
The number of protons in the nucleus of each kind of atom
Atomic number
A distinct form of the atoms of an element, all with the same number of protons but different number of neutrons
Isotopes
The total number of protons and neutrons in the atomic nucleus
Mass number
The amount of matter in an object
Mass
A standard unit of mass, around 1.66 x 10 - 23 grams
Dalton
The giving off of particles of matter and energy by decaying nuclei
Radioactivity
A measure of the pull of gravity of an object
Weight
An unstable, radioactive isotope
Radioisotope
A dating technique that uses clockwork decay of unstable isotopes to estimate the age of organic material, rocks, or fossils that contain them
Radiometric dating
The region of space where the electron lives most of the time
Orbital
Isotope used to label molecules so that they can be tracked as they pass through biochemical reactions
Tracers
Regions of space within an atom where electrons are found. Also referred to as shells
Energy levels
Regions of space within an atom where electrons are found. Also referred to as energy levels
Shells
Link formed when atoms of reactive elements combine into molecules
Chemical bonds
An electron in the outermost energy level of an atom
Valence electrons
A bond that results from electrical attractions between atoms that gain or lose valence electrons completely
Ionic bonds
A positively charged ion
Cation
A negatively charged ion
Anion
Bond formed be electron sharing between atoms
Covalent bonds
Bond in which electrons are shared equally or nearly equally. The atoms have no charge
Non polar covalent bond
The measure of the tendency of an atom to attract electrons to itself in a chemical bond (that is, to become negative)
Electronegativity
Bond in which electrons are shared unequally
Polar covalent bond
Association that occurs when polar molecules attract and align themselves with other polar molecules and with charged ions and molecules
Polar associations
In chemistry and biology, referring to polar molecules that associate readily with water
Hydrophilic
Association that occurs when non polar molecules clump together
No polar associations
Non-covalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen or sulfur atoms
Hydrogen bond
In chemistry and biology, referring to non polar substances that are excluded by water and other polar molecules
Hydrophobic
The three dimensional arrangement of the atoms in a molecule. Aka it’s shape
Molecular geometry
Weak molecular attractions over short distances
Van der waals forces
A reaction that occurs when atoms or molecules interact to form new chemical bonds or break old ones
Chemical reactions
The atoms or molecules entering a chemical reaction
Reactants
An atom or molecule leaving a chemical reaction
Products
An arrangement formed when a water molecule in liquid water establishes an average of 3.4 hydrogen bonds with its neighborS
Water lattice
A rigid, crystalline structure formed when a water molecule in ice forms four hydrogen bonds with neighboring molecules
Ice lattice
A chemical reaction written in balanced form
Chemical equations
The amount of heat required to raise 1g of water by 1•C; known as a small calorie; when capitalized, a unit equal to 1000 small calories
Calorie
The amount of heat required to increase the temperature of a given quantity of water
Specific heat
The scientific unit equivalent to a Calorie and equal to 1000 small calories
Kilocalorie
The heat required to give water molecules enough energy of motion to break loose from liquid water and form a gas
Heat of vaporization
The high resistance of water molecules to separation
Cohesion
The force that places surface water molecules under tension, making them more resistant to seperate on than the underlying water molecules
Surface tension
A surface coat of water molecules that covers other polar and charged molecules and ions
Hydration layer
A membrane with two molecular layers
Bilayer
The water in a solution in which the hydration layer prevents polar molecules or ions from reassociating
Solvent
Substance formed when molecules and ions separate and are suspended individually, surrounded by water molecules
Solution
The number of molecules or ions in a substance in a unit volume of space
Concentration
The molecules of a substance dissolved in water
Solute
The weight of a element in grams, equal to the mass number
Atomic weight
The number 6.022 x 10^23, derived by deciding the atomic weight of any element by the weight of an atom of that element
Avogadro’s number
The weight of a molecule in grams, equal to the total mass number of its atoms
Molecular weight
The number of moles of a substance dissolved in 1L of solution
Molarity
Amount of substance that contains as many atoms or molecules as there are atoms in exactly 12g of carbon-12, which is 6.022 x 10^23
Mole
The separation of water to produce positively charged hydrogen ions and hydroxide ions
Dissociate
The term indicating that a reaction may go from left to right or from right to left, depending on conditions
Reversible
Proton donor that releases H+ (and anions) when dissolved in water
Acids
Proton acceptor that reduces the H1 concentration of a solution
Bases
The numerical scale from 1 to 14 used by scientists to measure acidity
pH scale
The concentration of H+ in a water solution, as compared with the concentration of OH-
Acidity
Substance that compensates for pH changes by absorbing or releasing H+
Buffers
Rainfall with low pH, primarily created when gaseous wilder dioxide (SO2) dissolved in water vapor in the atmosphere, forming a sulfuric acid
Acid precipitation
