yet another science test Flashcards
electrons shared by 3 or more atoms are _____
delocalized
describes how strongly atoms of that element pull on electrons in chemical bonds
electronegativity
covalent bond where the atoms have equal electronegativity, so both atoms share their electrons equally, and the electrons are not pulled closer to one atom than to the other
nonpolar bond
covalent bond with unequal sharing of electrons
polar bond
molecule that has opposite partial charges on opposite ends
polar molecule
a substance consisting of atoms covalently bonded into a large structure that does not contain a specific number of atoms
covalent network
simplest ratio of atoms in a nonmolecular compound
formula unit
form of bonding created through the transfer of electrons
ionic bonding
attraction between the oppositely charged ions
ionic bond (between a metal and nonmetal)
ion formed from a group of atoms
polyatomic ion
negative ion
anion
positive ion
cation
form of bonding created through the sharing of electrons
metallic bonding
bonding in metals in which valence electrons are shared by all the atoms in the metal
metallic bonding
prefixes:
1. one
2. two
3. three
4. four
5. five
6. six
7. seven
8. eight
9. nine
10. ten
- mono-
- di-
- tri-
- tetra-
- penta-
- hexa-
- hepta-
- octa-
- nona-
- deca-
formula that tells how many of each type of atom are in a molecule
molecular formula
formula that shows the general arrangement of the atoms in a molecule
structural formula
formula that shows only the simplest ratio of atoms in a compound
empirical formula
strongest intermolecular force
hydrogen bond
weakest intermolecular force
London force
intermolecular force that affects nonpolar molecules
London force
intermolecular force that affects normal polar molecules
dipole-dipole force
intermolecular force that affects every type of molecule
London force
homogeneous mixture
solution
substance doing the dissolving in a solution
solvent
process where ions break apart into smaller ions
dissociation
three ways to increase the rate that a substance dissolves in a solution
- stir
- crush / grind
- heat
ability of one substance to dissolve in another substance to form a solution
solubility
a substance that dissolves easily in a solvent
soluble
a solid formed when a substance “undissolves”
precipitate
general rule explaining polar substances dissolve polar substances and nonpolar dissolve nonpolar
“like dissolves like”
Avogadro’s number
6.022 x 10 to the 23
unit representing Avogadro’s number
mole
measure of solution concentration as moles of solute per liters of solution
molarity
concentration measured as the moles of solute in a given mass of solvent (kilograms)
molality
process of mixing molecules of one substance with another substance by random molecular motion
diffusion
allow some substances to diffuse through them but not other substances
semipermeable
one-way diffusion through a semipermeable membrane
osmosis
expression that uses chemical symbols to represent a chemical reaction
chemical equation
substances that undergo change
reactants (on left side of chemical equation)
substances produced by change
products (on right side of chemical equation)
number before each chemical formula that shows how many molecules or formula units of that substance are involved in the reaction
coefficient
small number on the bottom right that tells how many elements are in the molecule
subscript
3CO(subscript 4) has ______ molecules
3
3CO(subscript 4) has ______ atoms
15 (12 in oxygen; 3 in carbon)
how many atoms of oxygen are there in 4Ca(OH) subscript 2 on (OH) ?
8 atoms of oxygen
states that the total mass of the reactants is equal to the total mass of the products
law of conservation of mass
AB -> A + B is a _______ reaction
decomposition
NaCl + AgNo -> NaNo + AgCl is a ______ reaction
double displacement
H(subscript 2) + I(subscript 2) -> 2HI is a ______ reaction
combination
AB + CD -> AD +CB is a ______ reaction
double displacement
the study of the relationship between chemical reactions and the laws of thermodynamics
chemical thermodynamics
a form of potential energy that may be released as thermal energy when molecules combine or break apart
chemical energy
chemical reaction that releases thermal energy
exothermic reaction
chemical reactions that cause thermal energy to be absorbed and stored in the chemical bonds of the products
endothermic reactions
a reaction that is able to occur by itself without continuing outside help
spontaneous
states that the entropy of the products can be lower than the entropy of the reactants only if the entropy of the surroundings increases by a greater amount
second law of thermodynamics
says that the energy gained or lost by a system equals the energy lost or gained by the surroundings
first law of thermodynamics
kinetic energy necessary for molecules to chemically react
activation energy
area of chemistry that addresses the rates of chemical reactions
chemical kinetics
substance that alters the rate of a chemical reaction without being permanently changed in the reaction
catalyst
four ways to increase reaction rate:
- heat (increase)
- surface area
- pressure/concentration
- catalyst
reaction that can be made to go backwards
reversible reaction
in a reversible reaction, if both reactions occur at the same rate, the system is in _______
chemical equilibrium
says that when a system at equilibrium is disturbed, the system will react to at least partially offset that disturbance
Le Chatelier’s principle
any ionic compound that does not contain a hydrogen ion (H+) or hydroxide ion (OH–)
salt
any substance that produces hydroxide anions (OH–) in aqueous solution
base
any substance that produces hydrogen cations (H+) when dissolved in aqueous (water) solution
acid
a cation of a base and an anion of an acid form a _____
salt
H(subscript3)O+
hydronium ion
_____ produces hydronium when dissolved in water
acid
acids and bases that completely dissociate or react to form hydroxide ions are ______
strong
acids and bases that only partially dissociate to form ions are _____
weak
a reaction that occurs when a strong acid reacts with a strong base
neutralization reaction
neutralization reactions form ____ and ____
salt and water
scale that represents the concentration of hydronium
pH scale
on the pH scale:
1. less than 7
2. 7
3. greater than 7
- acids
- neutral
- bases