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74 Cards in this Set
- Front
- Back
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What does chemistry try to understand?
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composition
structure and properties of substances |
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How is matter classified?
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elements
compounds mixtures |
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What is an element?
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substances that contain only one kind of atom
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What is a compound?
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substances that contain more than one element combined in fixed proportions
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What is a mixture?
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contains substances that do not combine in fixed ratios
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What is the difference between compounds and molecules?
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Compounds are composed of molecules; molecules are the smallest particles of a compound that retain the properties of the compound
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Identify the element, molecule and mixture:
Fe CO sugar and salt |
Fe - element
CO - molecule sugar and salt - mixture |
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What is a molecule?
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the smallest particle that has any of the properties of a compound
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What is the mass of an electron?
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9.11 x 10^-28
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What is the mass of a proton?
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1.673 x 10^-24
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What is the mass of a neutron?
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1.675 x 10^-24
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What is the relative mass between electrons, protons and neutrons?
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electron 0
proton 1 neutron 1 |
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What is an isotope?
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contains a different number of neutrons
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What are the 3 most commonly occurring isotopes of carbon?
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carbon-12
carbon-13 carbon-14 |
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What is the formula of:
Ammonium Carbonate Sulfate Phosphate |
NH4 1+
CO3 2- SO4 2- PO4 3- |
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What is a polyatomic ion?
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An ion that contains more than one atom.
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What is a group?
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vertical
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What is a row (period)?
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horizontal
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What is the relative abundance of 12C?
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98.89%
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What is the relative abundance of 13C?
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1.108%
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What is Avagadro's Number?
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6.022 x 10^-23
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What is the equation that is used to determine density?
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d=m/v
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Define the concentration of a solution.
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The ratio of the mount of solute to the amount of solvent or solution
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What is the formula for molarity (M)?
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Molarity = moles solute/liters of solution
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What is the speed of light?
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c = 2.998 x 10^8 m/s
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What equation do we use to find frequency and wavelength of a light wave?
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λv = c
c = 2.998 x 10^8 m/s |
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Which has more energy - light with a longer wavelength, or light with a shorter wavelength
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shorter wavelength
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What does "the energy of the light absorbed by a hydrogen atom is quantized" mean?
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hydrogen will emit or absorb discrete or fixed amounts of energy
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Why do atoms emit or absorb discrete amounts of energy?
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Electrons need a specific amount of energy to move from one shell to the next
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What is first ionization energy?
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energy required to move an electron from the lowest-energy state of a neutral atom to form a positive ion
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First ionization energies __ as we move from left to right across the periodic table.
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increase
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First ionization energies __ as we move from top to bottom down the periodic table.
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decrease
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Explain why the first ionization energy of hydrogen is so much larger than that of Na.
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the electrons are closer to the nucleus in a hydrogen atom, so they are closer to the positively charged protons; thus they are tougher to pull away
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What is core charge?
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positive charge on the nucleus minus negative charge of all electrons except for those in the valence shell
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What is the relationship between valence electrons, core charge and group number?
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they are the same numbers; core charge is the same as V and grp number for the main group elements
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When does an atom have no magnetic properties?
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when all electrons are spin-paired
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What group does this element belong to?
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3 |
5
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Metallicity increases from __ to __ across the periodic table
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right
left |
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According to Dalton, how do atoms of different elements differ?
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different elements are unique in their weights and properties
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How does the radius of an atom compare to the size of the nucleus?
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the radius is about 10,000 times bigger than the nucleus
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What is diffusion of a gas?
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rate at which two gases mix
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What is effusion of a gas?
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rate at which gas escapes through a pinhole into a vacuum
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What do Graham’s observations suggest about the relative speeds of molecules that have different molecular weights?
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light molecules travel faster than heavy molecules
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When does deviation from ideal gas behavior occur?
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when the gas is at low temperatures, or high pressures
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What is van der Waals equation?
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(P + (an^2 / V^2))(V - nb) = nRT
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In the van der Waals equation, what does b represent and what are the units used?
(P + (an^2 / V^2))(V - nb) = nRT |
rough measurement of the size of the particle
(L/mol) |
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In the van der Waals equation, what does a represent and what are the units used?
(P + (an^2 / V^2))(V - nb) = nRT |
attraction between particles
(L^2 x atm/mol^2) |
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Compounds for which the force of attraction between particles is strong have large values for a.
Therefore, compounds with large values of a would have __ boiling points. |
higher
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What is the first law of thermodynamics?
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Esys = q + w
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What is the difference between heat and temperature?
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temperature is the average kinetic energy of the molecules of a substance
heat is energy; total energy possessed by the molecules in a piece of matter |
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Explain the first law of thermodynamics:
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energy is conserved
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What is enthalpy?
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A measure of the energy change in the system plus work done to or by the system
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Three factors can affect the enthalpy of reaction:
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• The concentrations of the reactants and the products
• The temperature of the system • The partial pressures of the gases involved (if any) |
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What is bond energy?
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energy required to break a bond - always a positive number
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activity and metallic character __ down a column
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increase
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What are Group IA atoms called?
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Alkali metals
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What are Group IIA atoms called?
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Alkaline Earth Metals
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Describe coinage metals
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highly unreactive
essentially inert at room temp |
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Describe Group IA (alkali metals)
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react with weak and strong acids
only 1 valence electron |
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Describe Group IIA (alkaline earth metals)
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react only with strong acids
two valence electrons |
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Transition metals lose electrons from orbitals __ first and __ second.
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s
d |
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What are the formulas for:
Sodium oxide Sodium peroxide Sodium superoxide |
Na2O
Na2O2 NaO2 |
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Why are metals good conductors of heat and electricity?
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electrons flow easily in metals
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When does oxidation occur?
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when the oxidation number becomes more positive
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When does reduction occur?
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When the oxidation number becomes more negative
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Ionic bonds have ___ attraction.
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electrostatic
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What formula is used to find the oxidation number?
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OX = V - N
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1 atm = ___ mmHg
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760
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What is the oxidation state?
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charge that the central metal would have if all surrounding ligands and shared electron pairs were removed
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What kind of bond forms when the electronegativity in a compound is:
less than 1.2 between 1.2 and 1.8 more than 1.8 |
covalent
polar ionic |
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What is the electronegativity of a covalent bond?
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less than 1.2
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What is the electronegativity of a polar bond?
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between 1.2 and 1.8
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What is the electronegativity of an ionic bond?
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more than 1.8
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What two atoms make the most ionic bond?
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francium
fluorine |
