chem midterm Flashcards
pure substance
materials that are only one compound or element
mixture
contains more that one substance (homo or heterogenuos)
physical change
changes that occur without altering the identity (malting metal into a new form)
chemical properties
we cannot measure without changing identity (flamability)
energy
the ability to do work
Exothermic change
releases heat energy
Endothermic change
absorbs heat energy
metric prefixes
tera
gige
mega
kilo
standard one
deci
centi
milli
micro
nano
pico
sig fig rules
- All nonzero digits are significant,
and all zeros between nonzero digits are significant.
2.If a decimal point is present, zeros to the right of the last
nonzero digit are significant. - Zeros to the left of the nonzero numbers are never significant.
atomic theory
theory that all matter is composed of atoms
atoms of each element are unique
atoms can join together in ratios
atoms can react and burn the atom is still an atom
law of conservation
in chemical reactions matter is neithr created or destroyed (if you add one to another you just add each other)
how to calculate Fahrenheit
9/5 c + 32
how to calculate celcius
5/9(F-32)
how to calculate Kelvin
C+273.15
which was do groups/famalies go
down
which way do periods go
across