Chemistry exam Flashcards
chemistry is the study of
matter
matter is split into two subjects
substances and mixtures
substances are categorized into two forms
element and compound
elements
one type of atom
compound
two or more different atoms chemically bonded
(compounds are made of atleast two different elements at DEFINITE RATIO)
mixtures
two or more substances mixed at not definite ratio
mixtures are split into two categories
homogeneous and heterogeneous
homogeneous
solutions, mixture is the same throughout; visible to the naked eye
heterogeneous
colloids and suspensions, is not same throughout
5 rules for significant digits in multiplication and division
- all non zero numbers are significant (ex. 2,357 = 4 sigfig)
- trapped zeros are sig fig
(ex. 2005= 4 sigfig) - trailing zeros are significant if there is a decimal in the number anywhere (ex. 2.500)
- if there is no decimal trailing zeros are not sig figs
- starting zeros not significant
(ex. 0.0025 = 2 sig fig)
rules for applying sig fig for addition and subtraction
the final answer MATCHES the LEAST TOTAL digits after the decimal
ex. 0.0005 {4 digits}
+ 26.3 {1 digit}
1.29 {2 digits}
—————————————-
27.5905 = 27.6 {1 digit}
%error =
measured value - accepted value
% error = ——————– x100
accepted value
solution is always…
homogeneous
solids, gases, and liquids are all…
substances
the only phase that isn’t a substance is ______ and it is..
aqueous, mixture (homogeneous)
