chem test Flashcards
what is an element
pure substance that cannot be broken down
one type of atom
what is a compound
pure substance with 2+ different atoms
can be broken down chemically
physical vs chemical property
chemical is determined after undergoing a chemical reaction/ forming a new substance
physical vs chemical change
physical is state or form, chemical is rearrangement of atoms and new substance
some properties of metals
lustrous or dull good conductors solids at room temp malleable and ductile high melting and boiling
some properties of non metals
low or no luster suck at conducting solids or gases brittle solids low to moderate melting and boiling
properties of metalloids
lustrous or dull some are semiconductors solids brittle sometimes moderate melting and boiling
how do transition metals form ions
with multiple charges
smallest unit of an element
atom
lose two electrons, what is the charge
+2
an atom is electrically neutral if
of electrons = # of protons
metals lose electrons to form:
cations
non metals gain electrons to become:
anions
atomic number represents the number of:
protons (and electrons if neutral)
atomic mass:
protons and neutrons together
atomic symbol of chlorine:
Cl
iupac name for Au 3+
gold (iii)
iupac name for calcium ion
literally just calcium lol
suck it
prefix for seven
hepta
bohr model of the atom, planetary model. list ways it contributed.
- electron orbits around nucleus
- each orbit of electrons corresponds to energy levels
- the farther the electron is from the nucleus, the greater it’s energy
- electrons don’t lose energy travelling in energy levels
lewis symbols are convenient bc
they simply have the chemical symbol and a dot for each VALENCE electron
noble gases are fancy bc they’re:
stable. don’t need to lose or gain electrons
iso-electronic:
different atoms w the same number of electrons
bohr rutherford diagrams
Be 2e 2e
Isotope:
same element, different number of neutrons.
isotopes have the same number of protons but different masses bc:
atomic mass is determined by protons and neutrons, and isotopes have diff numbers of neutrons
atomic number vs atomic mass
number of protons vs number of protons and neutrons
ionic compound vs molecular compound
molecular shares electrons, ionic lends them
molecular: NON metals
ionic: metal + non metal
ionic bond:
electrostatic force from transferring electrons
some properties of ionic compounds
hard brittle solids crystal lattice structure DO NOT EXIST AS NEUTRAL MOLECULES strong ionic bonds=high melting points soluble in water conduct electricity
electrolytes:
substances that conduct electricity when dissolved in water
molecular compounds are formed by the joining of
neutral atoms (to form a molecule)
bonding pair:
a pair of electrons holding two atoms together
lone pair:
electrons not involved in a bond
single, single, triple covalent bond
one, two, three shared pairs
steps for drawing lewis structures of molecular compounds
- count valence electrons for all atoms
- central atom will need most electrons
- place bond between central atom and each surrounding atoms to connect them
- lone pairs around all surrounding atoms (not H)
- (optional): if central atom doesn’t have full octet or electrons are remaining, add them as line pairs around central atom
electronegativity
tendency of an atom to attract a shared pair of electrons
electrons are shared equally (electronegativity):
non polar covalent bond
electronegativity difference is less than 0.4
electrons are shared unequally (electronegativity):
polar covalent bond
electronegativity difference is 0.4 or higher, less than 1.7
in ionic bonding, electrons are transferred. if the electronegativity diff between two atoms is ___ or higher, the bond is ___
1.7, ionic
some properties of molecular compounds
solids liquids or gases composed of neutral atoms melting and boiling low to moderate some are soluble in water don’t conduct electricity NON electrolytes
prefix for 3
tri
when do you put prefixes?
molecular binary compounds only
prefix for nine
nono
prefix for 4
tetra
if compound has H before, it is an
acid
HCl = hydrochloride acid
tertiary acids: change ite to ___ and ___ to ic.
ous, ate
law of conservation of mass
matter is not created or destroyed
mass of reactants = mass of products
chemicals do NOT destroy or change ___ into other ___
atoms into other atoms
balanced version of
H2 (g) + O2 (g) = H2O
2H2 (g) + O2 (g) = 2H2O (l)
what state is a solution or acid
aq
synthesis reaction
two reactants, ONE new compound
decomposition reaction
compound breaks into two or more elements/compounds
reaction with oxygen: complete combustion
hydrocarbons + crapload of oxygen = ONLY carbon dioxide and water.
reaction with oxygen: incomplete combustion
hydrocarbons + smaller crapload of oxygen = 1+ of the following: CO2, CO, soot
when reacting with oxygen, what is always a product (to account for hydrogen)
water
reaction with oxygen: metals
form metal oxides or peroxides
reaction with oxygen: nonmetal
nonmetal oxides
reaction with oxygen: nonmetal oxides
produce other nonmetal oxides
single displacement:
ELEMENT + COMPOUND = new element + new compound
corrosion:
breakdown of metal resulting from reactions
metals that don’t corrode
gold, platinum
double displacement
two compounds = two new compounds
double displacement: precipitation
two new compounds, one being precipitate.
precipitate= insoluble in solubility table
double displacement: acid base neutralization
acid + base = water and a salt
if base is carbonate, CO2 is also produced
mole:
unit of measurement
mole of one substance is atomic mass
avodragos number
6.02 x 10 to the 23rd
molar mass
mass of one mile of any substance in g/mol
n = what
number of mol
M =
molar mass
m =
mass of sample
N =
number of entities (u/molecules/atoms)
NA =
6.02 x 10 to the 23rd entities/mol
n = m/?
n = m/M
n = ?/NA
n = N/NA
m/? = N/NA
m/M = N/NA
formula for stoich
given amount, convert to moles, molar mass, convert to desired units
ALWAYS BALANCE THE
EQUATION
AFTER ELEMENTS/COMPOUNDS, ADD
STATES
the ostwald process:
used for making nitric acid
important for the time
fundamental change in agriculture
properties of acids
corrosive sour tasting release hydrogen ions when dissolved pH is LESS THAN SEVEN electrolytes
properties of bases
corrosive bitter tasting release hydroxide ions when dissolved pH GREATER THAN SEVEN electrolytes
ionization:
molecular compounds dissolve to produce ions
dissociation:
ionic compounds dissolve to produce ions
Arrhenius’s theory of acids and bases:
acids are substances that dissociate in water to yield ions
pH:
measure of the concentratipn of hydrogen ions
pH scale:
measures the level of acidity and basidity
pH scale goes from 0-14. 14 is lowest ___ and highest ___
lowest acidity, highest basidity
from pH level 7 to 6, it gets ___ more acidic.
10x
pH level 0 (battery acid) formula
H > OH
pH level 7 (fresh water) formula
H = OH
pH level 14 (drain cleaner) formula
H < OH
pH of 11 is
moderately basic
pH of 2 is
very acidic
strong ACIDS ___ completely
ionize
weak ACIDS ___ partially
ionize
strong BASES ___ completely
dissociate
weak BASES partially react with
water
strong and weak acids and bases of similar concentration have ___ properties
different
acid base indicators (red cabbage) are chemicals that
change colour when reacting with bases or acids
acid base indicators change ___ with different pH levels
colour
nonmetal oxides react with water to form
acids
metal oxides react with water to form
bases
phosphoric acid is used in
soft drinks
windex is
ammonium hydroxide
how to determine the pH of a solution
acidic: H > 1 x 10 to the -7
basic: H < 1 x 10 to the -7
if you are given the H+ in mol/L, what formula
pH = -log(1x10 to the -6)
what is the pH of a solution with a H+ of 4.7 x 10 to the -11 mol/L
10.3
how to convert pH to H+
inverse log of the - pH
H = 10 to the -9 = 1 x 10 to the -9 mol/ L
what is the H+ of a solution with a pH of 2.8
1.6 x 10 to the -13 mol/L
how can the pH of a solution be changed
adding acid, base, or water
pH of normal rainwater, 0.0000026 mol/L
5.6
hydrogen concentration of drain cleaner, pH of 14
1 x 10 to the -14 mol/L
titration:
lab to find unknown concentration
CA VA = CB VB
c = n/v
NA = NB
titration formula
random example of acid base neutralization
baking: baking powder contains tartaric acid and sodium bicarbonate
bubbles of CO2 allow cake to rise as it bakes
acid precipitation
any form of precipitation that becomes acidic from reaction the compounds in the atmosphere
titration
process where a solution of known strength is added to a certain volume of a treated sample containing an indicator.
can two atoms be isotopes if they have different atomic numbers but same atomic masses?
no. their masses can be different but their atomic numbers must be the same.
if a lewis structure is of an ion, you must include the ion change of the
electrons
determine the bond type for O-O
electronegativity difference: 3.5 - 3.5 = 0
non polar bond
what is the bond type for S-Cl
electronegativity difference: 3-2.5=0.5
polar
bond type of Na-O
electronegativity difference: 3.5 - 0.9 = 2.6
differences between ionic and molecular compounds: PROPERTIES
ionic: high melting point, conduct electricity
molecular: low to moderate melting point, nonelectrical conductors
differences between ionic and molecular compounds: ELECTRONS
ionic: TRANSFER of electrons (metals to non metals)
molecular: electrons SHARED between nonmetals
what’s the difference between a strong and weak acid
strong acids ionize almost completely so there is a greater concentration of H+ ions, lower pH, and are more corrosive.
neutral solutions have a pH of
7
a solution with a pH of 4 has. a greater H+ than __
OH.
the diatomic elements
HOFBrINCl
what does HOFBrINCl stand for
diatomic elements hydrogen oxygen fluoride bromine iodine nitrogen chlorine
how many reactions in the ostwald process
three
rate of reaction
time it takes for a given amount of product/reactants to react or form
