Pre-Chem Studying

matter
-physical material of the universe
-anything that has mass and occupies space
elements
100 or so elementary substances
atoms
-building blocks of matter
-smallest particles of an element to retain its identity
states of matter
-solid
-liquid
-gas
pure substance
-matter that has distinct properties and a composition that does not vary from sample to sample
-ex: water and salt
compound
-substances composed of 2 or more elements
-contains 2+ kinds of atoms
mixtures
-combinations of 2+ substances where each substance retains its own unique identity
-can be separated
law of constant composition
elemental composition of a pure compound is always the same
solutions
homogeneous mixtures
physical changes
-changes appearance but not composition
-ex: evaporation of water
-incl all changes of state
chemical changes
-aka chemical rxns
-substance is transformed in to chemically different substance
-ex: when hydrogen burns in the air
mass
-measure of the amount of material in an object
-base unit is the kilogram
precision
how closely individual measurements agree with one another
accuracy
how closely individual measurements agree with the correct or “true” value
law of conservation of mass
-or matter
-atoms are neither created nor changed during chemical rxns
-total mass of materials present after a chemical rxn is the same as before
nucleus
-extremely small dense region at the center of at atom
-most of the mass of an atom
Tagged In :

Get help with your homework


image
Haven't found the Essay You Want? Get your custom essay sample For Only $13.90/page

Sarah from studyhippoHi there, would you like to get such a paper? How about receiving a customized one?

Check it out