Definitions Flashcards
Kelvin
K= c*+ 273
That means that when kelvin is at 273 Celsius is 0
0 Kelvin is Absolute Zero ( lowest temp in universe)
Kelvin scale absolute temperature
Fahrenheit is different
Intensive Property
Does NOT depend on amount (color,boiling point,freezing point, density)
Law of Conservation of Energy
Energy can not be destroyed, only changed into another
Law of definite Proportions
(1/2=50%, 1/2=50%) same proportion by mass
Substance
Matter which all samples have identical composition and proprties
Measurements in Chemistry
Length=meter (m),
mass= kilograms(Kg) , time=seconds(S) ,
Current=Ampere(A) , Temperature= kelvin(K) ,
Amount of substance=Mole(mol)
Weight
Measurement of the gravitational attraction for a body
Mass
Measurement of the quantity of matter in a body
Energy
Capacity to do work or transfer heat
Two types: potential energy and kinetic energy
1 meter
39.37 inches
Or 3.28 ft
Conversion factors of Length
1 inch = 2.54 cm
1 meter = 39.37 inches
1 meter = 3.28 ft
1 mile = 1.60 Km
Conversion factors of Volume
1gallon= 3.785 liters 1 gallon= 4 quarts 1 gallon= 2 pints 1 quart = 0.946 liters 1 pint = 0.473 liters
Conversion factors of Mass
1 pound = 453.6 g
1 Kg = 2.204 lb
1 oz= 28.34 g
Accuracy
How closely measured values agree with the correct value
Depends on operators skill and calibration of instrument
Precission
How closely individual measurements agree with each other
Depends on instrument quality and sensitivity
Precision precedes accuracy
Density
Density = mass (g)
_________
volume (ml)
D= m/ v. Or m= D x V. Or V= m/D
Significant figure rules
Leading zeroes are never significant
All non zeroes are significant
Zeroes at the end( trailing) are significant if they are preceded by a decimal point
Imbedded zeroes are significant
Fahrenheit
F= 9/5(c) + 32
Or F= (1.8 x c) +32
Specific Gravity
Same as Density, but without the symbols
Ex D= 11.4 g/ ml , specific grav= 11.4
Density substitute (g/ml)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
density of water (1.00 g/ml)Specific heat (s)
Amount of heat or energy necessary to raise the temperature of 1 gram of a substance by 1c*
q=m x s x ^t. Or s=q/m x ^ t –equation to finding specific heat
s= cal/ g x c. Or s= joule/ g x c– specific heat units
[q is heat energy in calories or joules, m is mass grams, s is specific heat cal or joules/ g x c*, ^ t is temp change ( initial-final temp)]
Units of Heat
Joule (si unit)and Calorie
1 calorie=4.184 joules
Calirometry
Measurement of heat changes
Exothermic process
Or endothermic process= absorption of heat
Heat
Total sum of Energy, kinetic + potential
Is extensive quantity, the more mass the more heat
Calorie
Heat or energy required to raise the temperature of 1 gram of WATER by 1 c*
Kilocalorie ,Kcal, is 1000 cal is 1 nutritional calorie
Atom
Smallest particle of an element that keeps its identity, stays the same through physical and chemical changes.
Molecule
Smallest part of an element that can have a stable independent existence in nature.
H2, O2, S2, H2O, CH4, C2H5OH
Homogeneous mixture
The same throughout, no physical boundaries and it doe not separate.
Air, milk, alloys, alcohol…
Heterogeneous mixtue
Mixtures are not the same throughout and posses boundaries
Sand, concrete, …
Metals
Good conductors of electricity and heat, shiny, ate monoatomic.
Alkali
Alkali earth
Transition
Non metals
Monoatomic, diatomic, or polyatomic
Diatomic. H2,N2 , O2,; halogens F2 ,Cl2 ,Br2 ,I2 .
Polyatomic: P4 ,S8; C60 ,C70
Ionic compounds
Metal and non metal, contain electric charge,
Change in anion must be the same as cation
Cations positively charged-ions, less than neutral
Anions negatively charged ions, more than neutral
Cations go in front of anions
Famous Ions
Cations: Na+, Ca +2, Al +3, NH4+ Ammonium Anions -1: Cl-,CN- Cyanide, SCN-Thiocyanate, MnO4-Permanganate OH- Hydroxide,C2H3O2-Acetate -2: SO4-2Sulfate, O2-2Peroxide, C2O4-2Oxalate, CrO4-2Chromate,Cr2O7-2Dichromate -3: CPO4-3 ,
Atomic Theory of Matter
Atoms are the building blocks of matter
Atoms of the same elements are identical physically and chemically
Atoms are neither created nor destroyed in chemical reactions
In chemical reactions they are rearranged united or separated to produce new substances
Atoms combined in a fixed proportion by weight to produce homoatomic molecules or heteroatomic molecules(compounds)
Formulas of ionic compounds
NaCl Sodium Chloride Na+ ,Cl-
KOH Potassium Hydroxide K+,OH-
CaSO4 Calcium Sulfate Ca+2,SO4-2
Al(COH)3 Aluminum Hydroxide Al+3 ,3OH-
More Ionic Compounds
H2SO4 Sulfuric Acid. FeBr2 Iron(II) bromide
C2H5OH Ethanol. HNO3 Nitric Acid
SO3 sulfur trioxide. FeBr3 Iron Bromide or Iron(III) Bromide
K2SO3 Potassium Sulfite—K2- , SO3-2
Atomic mass Diameter
1 x 10 -10 m
Rutheford
Atom is mostly open space
Nucleus is small dense center
Nucleus has most of the mass
Mass. 1/100,000
AMU
Atomic mass unit= atomic weight= found in the periodic table expressed in amu or amu/ atom
Is also the Relative Mass = the average of an element’s isotopes found in nature with their relative abundance.
Homoatomic molecules
Molecules made of the same element
Diatomic or polyatomic
O2,H2 ,C60
Atomic mass diameter
1x 10-10 meters approximately
Ex how many atoms in 1 .00 mm
1.00 mm. X 1 x 10-3 m. X 1 atom
__________. ________
1.00mm. 1 x10-10 m
Atomic mass
1 x 10-23g. Ex. 1.00 mg x 10-3 g. X. 1atom
__________. _______. ______
atom. 1 mg. 1 x10-23 g
Some chemical properties of metals
Outer shells contain few electrons
Form cations by loosing electrons
Form ionic compounds with nonmetals
Solid state characterized by metallic bonding
Some properties of non metals
Outer shells contain four or more electrons
Form anions by gaining electrons
Form ionic comp with metals and covalent comp with other non metals
Noble gasses are part of non metals
Nuclear density
15
10. g
_________
mL
James Chadwick
1932 discovered Neutrons
H.Gj Moseley
1913 said atomic # determines element
All elements differ by atomic #
Mole
Number of atoms, ions or molecules
Like a dozen = 12 of something
23
One Mole = 6.022.x 10. -Avogadro’s number
Molar Mass (MM)
Molar Mass in grams of an atom=to atomic weight in amu (atomic mass units) from periodic table of an element–g
Ex. Atomic weight of H is 1.00794
is expressed in g/mol or amu/atom
How to find # of Moles
Avogadros#.- from atoms to moles is one step
-from grams to moles. Is one step
- from atoms to grams. Are two steps
Atoms x Moles x grams. Or grams x Moles x atoms
1 mole of an element / 6.022 x 10 to23. — grams(atw)of an element/1mole
Ex. Mg atom to gram–
1 Mg atom X 1 mol Mg atom X 24.30g Mg
—————— ———– =4.04x10to23gMg
6.022x10to23Mg atoms. 1mol Mg atoms
