chem ch 2
micro- (u )
0.0001 (10^-4)
milli- (m)
0.001 (10^-3)
centi- (c)
0.01 (10^-2)
100 mL =______ L
0.1 L
The conversion factor of avagadro's number
1 mol / 6.022 x 10^23 or 6.022 x 10^23 / 1 mol
molar mass conversion factor
1 mole / x grams or x grams / 1 mole
avagadro's Number
1 mole = 6.022 x 10^23 "things"
molar mass equality
1 mole = x grams
kilo- (k)
1,000 (10^3)
How many atoms are in the elemental sample: 22.9 mol Hg
1.38 x 10^25 atoms Hg
how many moles are in a 22.5 g of O?
1.41 mol O
a helium balloon contains 0.462 moles of He, how many grams of He are in the baloon?
1.85 g He
Calculate the number of moles and the number of atoms of calcium contained in 1.28 g of Ca?
1.92 x 10^22 atoms Ca
molar mass of C
12.011 g/mol
molar mass of O
15.9994 g/mol
# of sig figs 0.0035
2 sig figs
0.250L=______mL
250 mL
0.000320
3 sig figs
1.23x10^-3
3 sig figs
How many mercury atoms are in 5.8 mol of mercury?
3.5 x 10^24 atoms Hg
molar mass of Cl
35.4527 g/mol
1.080
4 sig figs
2371
4 sig figs
100.00
5 sig figs
Calculate the mass of 2.25 x 10^22 tungsten atoms.
6.88 g W
0.06 m=______cm
6cm
600 cm=______m
6m
extensive property
Depends on the amount of a substance (mass, volume, weight)
Change in volume
Final - initial
Intensive property
Independent of the amount of the substance (density)
kilograms (kg)
SI unit for mass
Kelvin
SI unit for temperature
Seconds (s)
SI unit for time
Liters (L)
SI unit for volume
meters (m)
SIunit for length
Conversion factor
Writing the equality in the form of a fraction in order to move between units without changing the quantity
dozen
a counting number for 12
pair
a counting number for 2
score
a counting number for 20
work is
action of a force through a distance
kinetic energy
associated with motion
Potential energy
associated with positionor chemical composition
mole is use to count
atoms, molecules, and particles
Energy definition
capacity to do work
Calorie (Cal)
dietary equal to 1000 calories (cal)
Edothermic energy
energy entering a system
exothermic energy
energy is exiting a system
accuracy
got very close to the actual measurement but not as close and together
1 dozen = 12
infanant sig figs because it is a counting number
dimensional analysis
information given x conversion factor = information sought
Thermal energy
is the energy associated with the temperature of an object
total energy
kenetic +potential
Density
mass/volume = g/mL or g/cm^3
in scientific notation move to the right
negative exponent
in scientific notation moved to the left
positive exponent
Precistion
reproducing the measurements over and over
equalities
show the relationship between two units that measure the same quantity
joule (J)
the SI unit of energy
Molar mass
the atomic mass (amu) of an element is equal to the mass (in grams) of 1 mol of that element Atomic Mass =Mass of 1 mol
calorie (cal)
the english unit of energy
moles to "things" use ....
use avagadro's number
grams to mole use
use molar mass
sig figs in addition and subtaction
use the least number of decimal places
Sig figs in multiplication and division
use the weakest link method: the least number of significant digits
Can we count individual atoms?
we have no way to count individual atoms
