Unit 2 (chapter 3) Flashcards
atom
the fundamental unit of which elements are composed
chemical change
a change in the fundamental components of the substance
burning, rusting
new substances formed from original chemicals, usually difficult to reverse, energy is always given out or taken in resulting in temperature change, can result in color change due to new formation of products, new products can have a new state but don’t always
chemical property
property that can only be observed after changing a substance’s identity
flammability
decomposition
a chemical reaction in which one reactant breaks down into two or more products.
distillation
separates liquid from a solution
element
substance that cannot be decomposed into similar substances by chemical or physical means (consists of all atoms having the same atomic number)
extensive property
depends on how much substance you have (mass, volume)
filtration
separates insoluble solid from liquid
formula unit
the lowest whole number-ratio of ions in an ionic compound
heterogenous
visibly different or has visibly different parts
homogenous
visibly same throughout at eye level (solutions)
intensive property
does not depend on how much substance you have (color, density, melting point, solubility)
law of conservation of matter
matter cannot be created nor destroyed in any physical change
law of constant composition
a given compound always contains the same elements in the same proportion
law of multiple proportions
the same elements can combine in different whole ratios to form more than 1 compound
matter
anything that has mass and volume (density)
mixture
has two or more types of particles
variable composition- varied amount of substance
not chemically joined
each substance in the mixture keeps to its own properties
easily separated
ex: air, seawater, most rocks
molecule
group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
physical change
no new substances
usually easy to reverse
usually no significant energy change
usually no color change
substance usually changes state
no change in identity
size change
dissolving, cutting, bending, freezing, boiling, melting
physical property
a property that can be measured or observed without changing a substance’s identity
color, melting point, solubility
pure substance
only 1 type of particle, homogenous
solute
is dissolved
solution
homogenous mixture composed of two or more substances
solvent
does the dissolving
solid
particles are vibrating, touching, condensed. definite shape and volume
liquid
particles are touching, condensed. definite volume (determined by number of particles, size). can move
gas
particles are not touching, so far apart they have no impact on each other. constainer determines shape and volume (indefinite shape and volume).
melting
solid to liquid
freezing
liquid to solid
sublimation
solid to gas
deposition
gas to solid
evaporation
liquid to gas
condensation
gas to liquid
pure substances- elements
cannot be broken down, made of atoms
pure substances- compounds
can be broken down (decomposed), made of molecules or formula units
liquid and solid separation
property: size, density, color
technique: filter, decanting
liquid separation homo
property: boiling point
technique: distillation
liquid separation hetero
property: density, lack of solubility
technique: decanting
compound
definite composition- cannot vary
chemically joined
has properties that are different from the elements it contains
can be separated into elements using chemical reactions
ex: water, carbon dioxide, magnesium oxide, sodium chloride
paper chromatography
separates mixtures of colored components
ex: inks, dyes, coloring agents in food
Rf=distance moved by compound/distance moved by solvent
