Studied by 12 peopleWhat is mass?
amount of matter in an object
What is the unit for mass?
grams
What are moles?
unit for amount of substance
What is molar mass?
mass of one mole of a substance
What is the unit for molar mass?
g/mol
How do you go from mass to moles and vice versa?
molar mass
How do you go from particles of a substance to moles and vice versa?
6.02 x 10^23 (Avogadro's number) particles
How do you go from volumes of a gas at STP to moles and vice versa?
22.4 L of gas
What is STP?
0° Celsius and 1 atm
How do you go from volumes of a gas not at STP to moles and vice versa?
PV = nRT
P (pressure) = atm
V (volume) = L
n = moles
R (constant) = 0.0821
T (temperature) = Kelvin
What does macroscopic mean?
refers to substances and objects that can be seen, touched, and measured directly
What does particulate mean?
refers to the small particles, such as atoms and molecules that make up all matter
What is Dalton's atomic theory?
all substances are made of atoms, which are the smallest particles of matter and cannot be divided into smaller particles, created, or destroyed;
all atoms of the same element are alike and have the same mass and atoms of different elements are different and have different masses;
atoms join together to form compounds, and a given compound always consists of the same kinds of atoms in the same proportions
What is mass spectrometry?
technique that separates particles according to their mass
What is on the x-axis of a mass spectrometry graph?
mass number
What is on the y-axis of a mass spectrometry graph?
isotope abundance
What is an isotope?
atoms of the same element that have different numbers of neutrons
What is the atomic number?
number of protons
Where is the atomic number located on an isotope symbol?
bottom left
What is the mass number?
number of protons and neutrons
Where is the mass number located on an isotope symbol?
top left
How do you calculate average atomic mass?
amu = (mass of isotope A) (percent abundance of isotope A) + (mass of isotope B) (percent abundance of isotope B) ...
What is the average atomic mass?
weighted average of the atomic masses of the naturally occurring isotopes of an element
How do you calculate masses of molecules?
add the mass number of the atoms making up the molecule
What is the law of definite proportions?
proportion, by mass, of elements in a compound is always the same
What is the law of multiple proportions?
when elements combine to form different compounds, with different properties, the ratio of masses between elements within these compounds were whole number multipliers of the masses of the elements
What is the empirical formula?
simplest whole number ratio of atoms of each element in a compound
What is the molecular formula?
actual number of atoms of each element in a molecule
How do you find the empirical formula?
(1) if percents, change all to mass, (2) change masses to moles, (3) find element with smallest number of moles and divide the other elements by the smallest number of moles, (4) multiply all numbers by the same thing to get a whole number
How do you find the molecular formula?
(1) obtain empirical formula, (2) calculate molar mass of empirical formula, (3) divide given molar mass of unknown compound by molar mass found in (2), (4) multiply all subscripts of empirical formula by number found in (3)
How do you calculate percent composition?
(mass of element / molar mass) x 100
How do you go from mass to molar mass?
(mass / 1 molecule) x (6.02 x 10^23 molecules / 1 mole)
How do you find the empirical formula when only given a ratio of the masses of the elements?
(1) add the ratio of the masses of elements together to find the total mass of the substance, (2) divide the ratio of the mass by the total mass to get the percentage, (3) find the empirical formula as normal
How do you calculate the molar mass of element A when given the formula AxBy, the mass of element A, and the percentage of element B?
(1) convert mass of element B to moles of element B, (2) convert moles of element B to moles of element A, (3) divide given mass of element A by moles of element A found in (2)
How do you find the empirical formula of a hydrate when given the mass of the hydrate and the mass of the remaining substance after the hydrate was heated?
(1) subtract mass after it was heated from mass of the hydrate to get mass of H2O, (2) find the empirical formula as normal
How do you find the empirical formula of a hydrate when given the formula of the hydrate and the molar mass of the hydrate?
(1) find the molar mass of the ion on its own, (2) subtract mass of ion found in (1) from the given molar mass of the hydrate to get mass of H2O, (3) convert mass of H2O to moles of H2O
How do you find the mass of the ion that remains after the hydrate is heated when given the mass of the hydrate before the water has evaporated?
(1) find the molar mass of the ion and the molar mass of water and add them, (2) divide the molar mass of the ion by the molar mass of the hydrate found in (1), (3) multiply the number found in (2) by the given mass
How do you find the molecular formula of a gas at STP when given the percentages of the elements and the mass and volume of the gas?
(1) find the empirical formula of the gas, (2) find the molar mass using the empirical formula, (3) convert volume of the gas to moles, (4) divide the given mass of the gas by the moles of the gas found in (3) to get the molar mass of the gas, (5) find molecular formula as normal
How do you find the mass of oxygen when given only the total mass of the substance and the mass of CO2 and H2O?
(1) convert grams of CO2 and H2O to carbon and hydrogen, (2) subtract the grams of carbon and hydrogen from total mass of the compound to get mass of oxygen
What is matter?
anything that occupies space and has mass
What are the four states of matter?
solid, liquid, gas, plasma
What is a solid?
rigid and possesses a definite shape
What is a gas?
takes both the shape and volume of its container
What is a liquid?
flows and takes the shape of its container
What is plasma?
gaseous state of matter that contains appreciable numbers of electrically charged particles
What is weight?
refers to the force that gravity exerts on an object
What is the law of conservation of matter?
there is no detectable change in the total quantity of matter present when matter converts from one type to another
What is a pure substance?
substance that has a constant composition
What is an element?
pure substance that consists entirely of one type of atom
What is a compound?
two or more elements chemically combined
What is a mixture?
combination of two or more substances that are not chemically combined
What is a homogeneous mixture (solution)?
mixture that is the same throughout
What is a heterogeneous mixture?
mixture in which the composition is not uniform throughout
What is an atom?
smallest part of an element that has the properties of that element and can enter into a chemical combination
What is quantitative analysis?
determination of the amount or concentration of a substance in a sample
What is titration analysis?
process of adding a known amount of solution of known concentration to determine the concentration of another solution
What is the titrant?
solution containing known concentration
What is the analyte?
solution containing substance whose concentration is to be measured
What is the equivalence point?
point at which neutralization occurs
What are indicators?
specials types of compounds that change color as the pH of a solution changes
What is the end point?
point at which the indicator changes color
What is gravimetric analysis?
sample is subjected to some treatment that causes a change in the physical state of the analyte that permits its separation from the other components of the sample
What is spectroscopy?
analysis of the way in which atoms absorb and emit light
How do you calculate mass percentage of a substance in a mixture?
mass of substance / total mass of mixture x 100
What is the order that you should balance an equation?
metals, ions, nonmetals, oxygen, hydrogen
What is the net ionic equation?
equation for a reaction in solution that shows only those particles that are directly involved in the chemical change
What are spectator ions?
ions that do not participate in a reaction
How do you find net ionic equation?
(1) separate molecule down into basic elements and writing their charges and states, except for polyatomic ions and solids, (2) cross out spectator ions, which do not change
What are quantum numbers?
numbers that specify the properties of atomic orbitals and the properties of electrons in orbitals
What are the four quantum numbers?
n, l, m, s
What is the principle quantum number?
energy level
What is the angular quantum number?
shape of orbital
What is the magnetic quantum number?
indicates the orientation of an orbital around the nucleus
What is the spin quantum number?
specifies the spin of electrons
What are the four orbitals (sublevels)?
s, p, d, f
How many electrons can there be in the s orbital?
2 electrons
How many electrons can there be in the p orbital?
6 electrons
How many electrons can there be in the d orbital?
10 electrons
How many electrons can there be in the f orbital?
14 electrons
What are energy levels?
fixed energies an electron can have
How many electrons are in the first energy level?
2 electrons
How many electrons are in the second energy level?
8 electrons
How many electrons are in the third energy level?
18 electrons
How many electrons are in the fourth energy level?
32 electrons
What is Coulomb's Law?
F=q1q2/r^2
What is Coulomb's Law used for?
if the distance (r) is greater, then the nuclear charge (q) is lower, therefore the force of attraction is going to be smaller
What is the Aufbau principle?
electrons occupy the orbitals of lowest energy first
What is Hund's rule?
every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin
What is the Pauli Exclusion Principle?
no two electrons in the same atom can have the same set of four quantum numbers
What is the electron configuration?
1s2 2s2 2p3...
What is noble gas electron configuration?
[noble gas] 3s2...
What are valence electrons?
electrons in the outermost shell
What denotes valence electrons in the electron configuration?
valence electrons are the electrons in the highest energy level, therefore the largest number in the electron configuration
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