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)
solids have..
solids (s)
-definite shape [geometric}
-definite volume
-vibrational motion
gases have..
gases (g)
-no definite shape
-takes the shape of container if there is a lid
-no definite volume
liquids have..
liquids (l)
-no definite shape
-take shape of container
-definite volume
aqeous
aqeous (aq)
-mixture (homeogenous)
-NOT a substance, a solution
-substance dissolved in water
mass
the amount of matter an object takes
weight
the amount of gravity pushing u
if the mass is higher, the density will….
increase as well
density is
a comparison of how much matter there is in a certain amount of space
(how tightly packed everything is)
kinetic energy
motion of particles
potential energy
stored energy
solid has the least _______ energy
kinetic
gas has the highest _______ energy
kinetic
lowest kelvin temperature
0 (absolute zero)
when one energy changes, the other energy….
stays the same
exothermic is
decreasing cooling curve \
endothermic is
increasing heat curve /
Celsius boiling point
100 C
order of endothermic (/) heat curve
ALL ENERGY INCREASING
/A - B/: Solid {K.E increasing}
___B - C___: solid to liquid = solidifies/freezes {P.E}
/C - D /: liquid = reaches boiling point at D {K.E}
__D - E__: liquid to gas = boiling/vaporization {P.E}
/E - F/: gas {K.E}
order of exothermic cooling curve
ALL ENERGY DECREASING
/F - E/: gas {K.E decreasing}
__E - D__: gas to liquid {P.E decreasing}
/D - C/: liquid {K.E decreasing}
__C - B__: liquid to solid= freezes/solidifies {P.E}
/B - A/: solid {K.E decreasing}
melting is also known as
fusion
solidifying is also known as
freezing
For every change in KE there is the same type of change in
temperature
Potential Energy on the graph is
( ______ or /)
______
Kinetic Energy on the graph is
( ______ or /)
/
sublimation
substances changing phases from solid to gas directly (skipping liquid phase)
deposition
the opposite of sublimation, gas changing into solid
1kj=
1000j
precision on a bullseye is
when all the marks are close together, not necessarily next to the bullseye
accuracy on a bullseye is
when all marks hit the bullseye
