CHEM 120A Terms + Conversions

all terms from lecture slides + metric conversions !!

atom

the smallest particle of an element that cannot be chemically or mechanically divided into smaller particles

element

a pure substance that cannot be separated into simpler substances

compounds

a pure substance composed of two or more elements that are chemically bonded in fixed proportion

law of definite proportions 

a compound always contains the same proportion of its component elements

classification of matter

law of multiple proportions

when it is possible to have two different masses of one element react with a given mass of another element, the two masses of the first element must be a small, whole-number ratio

pure substances

a form of matter that contains only one type of particle, meaning it's either a single element or a single chemical compound

intensive properties

property that is independent of the amount of substance

extensive properties

property that is dependent on the amount of a substance

physical properties

properties that can be measured without changing the substance into another substance

chemical properties

properties that can be observed only by reacting the substance with something else to form another substance

density

the ratio of the mass (m) of any substance or object to its volume (V)

d=m/v

homogeneous mixture

mixture that has substances distributed uniformly, and the composition and appearance of the mixture are uniform

heterogeneous mixture

mixture that has substances that are not distributed uniformly and contain distinct regions of different composition

distillation

a process of purifying a liquid compound (separation) by heating it into a vapor that is then condensed back into a liquid

filtration

process that separates solids from liquids or gases using a filter medium that allows the fluid to pass through but not solid particles (think: pasta)

chromatography

technique for separating the components, or solutes, of a. i tire on the basis of the relative amounts of each solute distributed between a moving fluid stream, called the mobile phase, and a contiguous stationary phase; the mobile phase may be either a liquid or gas, while the stationary phase is either a solid or a liquid

solid

has a definite shape and volume 

liquid

occupies a definite volume but takes the shape of its container

gas

has neither a definite volume nor a definite shape

sublimation

solid → gas

melting

solid → liquid

vaporization

liquid → gas

condensation

gas → liquid

freezing

liquid → solid

deposition

gas → solid

energy

capacity to do work 

work

the exertion of a force (F) through a distance (d) → w = f x d

law of conservation of energy

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

potential energy

the energy stored in an object because of its position or composition

kinetic energy

energy of motion → KE = 1/2mu²

ionic compounds

compound that contains ions (charged particles) held together by attraction of opposite charges

metric system prefixes (separate set for these!) 

equation for celsius/fahrenheit

T(C) = (5/9)[T(F) - 32]

equation for kelvin

T(K)= T(C) + 273.15

precision

based upon the reproducibility of a measurement or the agreement between values

accuracy

refers to how close a measured value is to the true value

sig fig rules !!

unit conversions (separate deck made for these!!)

standard deviation

a measure of the amount of variation, or dispersion, in a series of related values

confidence interval

a range of values that has a specified probability of containing the true value