CHEM 3a - test 1

SI unit for mass

kilogram

SI unit for length

meter

SI unit for time

second

SI unit for temperature

kelvin

Atomic theory

John Dalton

Trueness

how close an average measurement is to an accepted value

precision

how close repeat measurements are to each other

significant figures

related to the amount of uncertainty/resolution of a measurement

scientific law

summary of a large number of observations

hypothesis

a tentative interpretation of the observations

trueness measurement

percent error

precision measurement

standard deviation

international system of units

the system of using standards as a basis for the metric system

scientific theory

a model that explains and gives the underlying cause of observations and laws

weight

measurement of force

observation

a measurement or observation of some aspect of nature

work

force applied over a distance

electron discovered

J.J Thomson

nucleus discovered

Rutherford

mixture

a compound of different substances that are in indefinite proportions

heterogeneous mixture

a mixture where two or more components are distinguishable from each other

crystalline solid

atoms or molecules are arranged in geometric patterns with long-range, repeating order

potential energy

energy based on position or composition

homogeneous mixture

a mixture where each component is indistinguishable from each other

energy

capacity to do work

chemical property

a property that is displace through changing its composition

liquid

indefinite shape, definite volume

gas

compressible

solid

definite shape

gas

indefinite volume

kinetic energy

energy associated with motion

pure substance

composed of only one type of atom or molecule

solid

close together but cannot move freely

gas

far apart

solid

oscillate around a fixed point

liquid

close together and can freely move

amorphous solid

does not have any long-range order

liquid

assumes shape of container

gas

assumes shape and volume of container

compound

composed of 2 or more elements in fixed definite proportions

element

can’t be broken down into simpler substances

physical property

substance displays without changing its composition

Mendeleev’s periodic table

ordered by increasing mass

volatile liquid

easily evaporates

involatile liquid

hard to evaporate

noble gases

group 8A

melting

solid to liquid

sublimation

solid to gas

vaporization

liquid to gas

fusion

solid to liquid

proton amu

1 amu

proton charge

1+

neutron amu

1 amu

neutron charge

0

electron amu

1/2000 amu

electron charge

1-

metalloids

intermediate electrical conductivity

temperature

measurement of thermal energy

evaporation

liquid to gas

halogens

group 7A

freezing

liquid to solid

vaporization

liquid to gas

sublimation

solid to gas

law of constant composition

Joseph Proust

polyatomic atoms

groups of atoms that act as a unit

empirical formula

gives relative number of atoms of each element in a compound

molecular formula

gives actual number of atoms of each element in a molecule of the compound

molecular compounds

compounds formed from 2 or more nonmetals

ionic compounds

one or more cation paired with 1 or more anion (metal + nonmetal)

exothermic

energy is released

endothermic

energy is absorbed