Chemistry Vocab

reactant

each chemical species that appears to the left of the arrow

product

each species that appears to the right of the arrow

combination

two or more reactants combine to form a single product

decomposition

two or more products form a single reactant

combustion

a substance burns in the presence of oxygen; produces CO2 and water

double displacement

metathesis, exchange; can be precipitation reaction or molecular product

single displacement

one solid metal exchanges to produce a different solid metal or hydrogen or halogen

neutralization

acid/base to get salt/water

condensation

two molecules combine and water is released

molecular equation

compounds are represented by chemical formulas as though they exist in solutions as molecules or formula units

net ionic equation

an equation that includes only the species that are actually involved in the reaction

spectator ions

ions that appear on both sides of the equation

electrolyte

a substance that dissolves in water to yield a solution that conducts electricity (ionic)

nonelectrolyte

a substance that dissolves in water to yield a solution that does not conduct electricity

strong electrolyte

an electrolyte that dissociates completely

weak electrolyte

a compound that produces ions upon dissolving but exists in solution predominantly as molecules that are not ionized

dynamic chemical equilibrium

when both forward and reverse reactions occur at the same rate

precipitate

an insoluble product that separates from a solution

precipitation reaction

a chemical reaction in which a precipitate forms

hydration

when water molecules remove the individual ions from an ionic solid surrounding them so the substances dissolve

solubility

the max amount of solute that will dissolve in a given quantity of solvent at a specific temperature

Arrhenius acid

one that ionizes in water to produce H+ ions

Arrhenius base

one that dissociates in water to produce OH- ions

Bronsted acid

acid that is a proton donor

Bronsted base

base that is a proton acceptor

hydronium ion

bronsted acids donate protons to water to formm H3O+

monoprotic acid

acid that has only one proton to donate

polyprotic acid

acid that has more than one acidic hydrogen atom

diprotic acid

acid that has two acidic hydrogen atoms

neutralization reaction

a reaction between an acid and a base; produces water and a salt

redox reaction (oxidation-reduction)

a chemical reaction in which electrons are transferred from one reactant to another

oxidation number

the charge an atom would have if electrons were transferred completely

oxidation state

the oxidation number; alternative name

activity series

a list of metals (and hydrogen) arranged from top to bottom in order of decreasing ease of oxidation

half-reaction method

balancing the electrons before adding the 2 half reactions

disproportionation reactions

occur when the element undergoes both oxidation and reduction

limiting reactant

the reactant used up first in a reaction

excess reactants

those present in quantities greater than necessary to react with the quantity of the limiting reactant

combustion analysis

the experimental determination of an empirical formula

theoretical yield

the amount of product that forms when all the limiting reactant reacts to form the desired product

actual yield

the amount of product actually obtained from a reaction

percent yield

what percentage the actual yield is of the theoretical yield

titration

technique used to perform quantitative studies of acid-base neutralization reactions

gravimetric analysis

an analytical technique based on the measurement of mass

equivalence point

the point in the titration where the acid has been neutralized

indicator

what brings about the color change

endpoint

the indicator chosen so that the color change is very close to the equivalence point

reduction agent

the compound that contains the element/ion that is oxidized and causes reduction

oxidizing agent

the compound that contains the element/ion that is reduced and causes oxidation

system

part of the universe that is of specific interest

surroundings

constitute the rest of the universe outside the system

thermochemistry

the study of heat (the transfer of thermal energy) in chemical reactions

exothermic process

occurs when heat is transferred from the system to the surroundings

endothermic process

occurs when heat is transferred from the surroundings to the system

calorimetry

the measurement of heat changes

specific heat

the amount of heat required to raise the temperature of 1g of the substance by 1 C

heat capacity

the amount of heat required to raise the temperature of an object by 1 C

thermodynamics

study of the interconversion of heat and other kinds of energy

open system

can exchange mass and energy with the surroundings

closed system

allows the transfer of energy but not mass

isolated system

does not exchange either mass or energy with its surroundings

state functions

properties that are determined by the state of the system, regardless of how that condition was achieved

first law of thermodynamics

states that energy can be converted from one form to another, but cannot be created or destroyed

q is positive

heat absorbed by the system (endothermic)

q is negative

heat released by the system (exothermic)

w is positive

work done on the system by the surroundings (ex: a volume decreases)

w is negative

work done by the system on the surroundings (ex: a volume increase)

enthalpy of reaction

the difference between the enthalpy of the products and the enthalpies of the reactants

standard enthalpy of formation

the heat change that results when 1 mole of a compound is formed from the constituent elements in their standard states

standard enthalpy of reaction

the enthalpy of a reaction carried out under standard conditions

Hess’s Law

the change in enthalpy for a stepwise process is the sum of the enthalpy changes for each of the steps

reactant

for an endothermic reaction, is heat a reactant or product

product

for an exothermic reaction, is heat a reactant or product

chemistry

the study of matter and the changes that matter undergoes

matter

anything that occupies space and has mass

mixture

can be separated by physical means into its components w/o changing the identities of the compounds

substance

a form of matter that has definite composition and definite properties

homogeneous mixture

mixture that is uniform throughout

heterogeneous mixture

mixture that is not uniform throughout

quantitative properties

measured and expressed with a number

qualitative properties

do not require measurement and are usually based on observation

physical properties

one that can be observed and measured without changing the identity of the substance

chemical property

one a substance exhibits as it interacts with another substance

chemical change

one that results in a change of composition; the original substances no longer exist

extensive property

depends on the amount of matter

intensive property

does not depend on the amount of matter

Law of Conservation of Mass

there is no detectable change in mass during an ordinary chemical reaction

molecule

consists of two or more atoms joined together by chemical bonds

atomic mass unit (amu)

used to express the masses of atoms and other similar sized objects

The Kelvin Scale

way of measuring temperature, lowest possible temp is 0 (absolute zero)

exact numbers

those that have defined values/are those determined by counting

inexact numbers

measured by any method other than counting

significant figures

the meaningful digits in a reported number

accuracy

how close a measurement is to the true value

precision

how close a series of replicate measurements are to one another

conversion factor

a fraction in which the same quantity is expressed one way in the numerator and another way in the denominator

element

a substance that cannot be broken down into two or more simpler substances by any means

Law of Constant Composition

a chemical compound always contains the same elements in the same proportions; also called the Law of Definite Proportions

protons

positively charged particles found in the nucleus

neutrons

electronically neutral particles found in the nucleus (slightly larger)