Chapter I Flashcards
how many SF do exact #’s have
infinite
for multiplication/division, answer has _____ for sig figs/LSP
has same # of SF as least precise factor
for addition/subtraction, answer has _____ for sig figs/LSP
has same LSP as factor w/ furthest-left one; nothing to do w/ sig figs
when calculating something that uses a mix of the 4 operations, how do you show your work (3 things)
- do add/sub 1st, mult/div 2nd
- do not round the # until the final answer, but still keep track of the # of sig figs & LSP
- show answer that calc gave as well as the final rounded answer
1 Terameter equation
1 Tm = 1 x 10¹² m
1 Gigameter equation
1 Gm = 1 x 10⁹ m
1 Megameter equation
1 Mm = 1 x 10⁶ m
1 Decimeter equation
1 dm = 1 x 10⁻¹ m
1 Micrometer equation
1 µm = 1 x 10⁻⁶ m
1 Nanometer equation
1 nm = 1 x 10⁻⁹ m
1 Picometer equation
1 pm = 1 x 10⁻¹² m
1 Femtometer equation
1 fm = 1 x 10⁻¹⁵
conversions aren’t exact #’s, T or F
F
3 things about density
- D = m/v
- take m & v from the same sample
- use pipet/grad cylinder for liquid v
3 steps to show calculations w/ conversions
1) show the original equation you use
2) show the equation w/ #’s subbed in
3) show ans w/ proper sig figs & units
def accuracy
close to correct value
def precision
close to other results
conversion from K to °C
Tₖ = T°꜀ + 273.15
conversion from °F to °C
T°բ = 1.8(T°꜀) + 32
3 ways to separate mixtures
- Decant (pour liquid off sediment)
- Filtration
- Distillation (boiling)
def intensive - 3 things
- physical prop
- doesn’t dep on amt of subst there
- used to ID subst
def extensive - 3 things
- physical prop
- does dep. on amt of subst there
- like mass, vol, heat content
what does a chem form show
compound, like H2O
what does a chem equation show
a reaction
2 defs of energy
capacity to work/transfer heat
equation for work
force x distance
what type of energy do chem bonds have
potential
3 energy abbv
Joule = J calorie = cal kilocalorie = Cal (food calorie)
conversion from cal to Cal
1000 cal = 1 kcal
time abbv for: second minute days hours years months millisecond microsecond nanosecond
s. min. days hr. yr. months ms µs ns
mass abbv for:
pounds
tons
lbs.
tons
temp abbv for:
celsius
fahrenheit
absolute 0
°C
°F
Ø K
length abbv for: inch centimeters kilometers feet yard mile millimeter micrometer meter
in. cm km ft. yd. mile mm µm m
volume abbv for: cubic centimeter gallon pint quart
cm³ or cc
all those are the words
6 SI units + the 3 we use in chem class length mass time temp substance amt elec current
m in real, cm in class kg in real, g in class s K in real, °C in class mol ampere
when to use sci notation for small #’s
more than 3 0’s in # (0.0003 - use it)
when to use sci notation for big #’s
more than 4 0’s in # (30000 - use it)
what multiplication symbol to use for scientific not
x, not * or ⋅
how to show multiplication outside of scientific not
() or *, not ⋅ or x
if there is a decimal @ the end of a # to put in sci not, like 3700., how do you write it?
include the 0’s: it turns into 3.700 x 10³
what is the error bar if untold
± a unit of the #’s LSP (for 3700, error bar = ± 100)
you can use fractions in science, T or F
F
2 points about estimating digits when measuring w/ a ruler
- the last digit of the recorded measurement is estimated
- if the intervals are at 2 cm, divide them into 20 places to get the estimated digit
4 steps to scientific approach
1) observe/experiment; find laws (patterns) in data
2) list hypotheses; test each w/ a new observation to disprove them (can’t prove)
3) summarize patterns, results, what it supports/doesn’t
* 4) much testing -> hard-to-disprove theory
def matter
has vol & mass
def atoms
smallest element unit; smash it & it’s no longer one of the elements
def compound
2+ atoms w/ physically unbreakable bond
def molecule
compounds existing individually; covalent
def bond
atoms’ attraction in a compound
def pure substance
pure element/comp (but we only ever say “pure subst”)
def mixtures
physically separable
2 types of solids
crystalline & amorphous
conversion between in & cm
1 in. = 2.54 cm
1 gal = how many L
3.785
3 things to write on test when calculating dimensional analysis
1) the conversion factors between the unit had & the unit wanted
2) write the conversion factors as 2 equal fractions (like 12in/ft = ft/12in)
3) Write it all on a line and put it through the calculator
Define chem property
the way a substance can change or react to form another substance
