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CEM 141
Final Exam Flashcards
| Question | Answer |
|---|---|
| molecules and atoms by themselves are both considered ________. | discrete |
| what is the evidence that electrons are ngativley charged particles? | the beam of particles bends toward the positvley charged plate |
| what is the reasoning that electrons are negativley charged particles? | objects with opposite charges attract each other through the electrostatic force |
| how did Rutherford's gold foil experiment change the model of the atom? | the gold foil experiment provided evidence that the positive charge in an atom is concentrated within the nucleus |
| what is true about scientific theories? | they can be used to predict the results of future experiments, they must change if their predictions are not verified by experiment, and they are based on the best evidence available |
| true or false: theories describe a phenomenon but cannot be used to explain it. | false |
| what is true about both gravitational and electrostatic forces? | they increase when the distance between the objects decreases |
| what causes the repulsive force between two neon atoms as they approach each other? | the atoms electron clouds overlap and the negatively charged electrons repel |
| on a potential energy graph where are the atoms most stable? | at the lowest point before the graph shoots up because that is where the attractive and repulsive forces are balanced |
| molecules in the liquid state are touching. liquids are ________ because the molecules cannot move closer together. | incompressible |
| when a substance boils how is energy transferred and in what direction is energy transferred at the atomic level? | energy is transferred when the substance atoms in the system collide with atoms in the surroundings, energy is absorbed into the system |
| what does not contain atoms? smoke, light, air, gold, or water | light light is energy |
| atoms with ________ LDF's require less energy to overcome, the LDF's are weaker because the atom is ________ than other atoms. | weaker, smaller |
| what is the evidence that I2 has a higher boiling point than Br2? | I2 has more electrons than Br2 |
| what is the reasoning that I2 has a higher boiling point than Br2? | since the iodine molecule has more electrons, this results in larger charges on the instantaneous dipoles in I2, larger charges cause stronger LDF's that require more energy to overcome when it boils |
| compare the energy changes when two helium atoms combine to the energy changes that occur when two hydrogen atoms combine. | less energy is released when two helium atoms combine because LDF's are weaker than covalent bonds |
| what is true for both LDF's and covalent bonds? | they are both attractive electrostatic attractions |
| what is the limiting reactant in a reaction? | they one that has less and limits the number of molecules made |
| scientific question: | testable or measurable |
| claim: | target of explanation |
| evidence: | data/scientific principle to support your claim |
| reasoning: | connection between your claim and evidence |
| which is the biggest? - atom - molecule - cell | cell (molecule is made up of atoms, and a cell is a collection of molecules) |
| what differentiates one element from another? | the number of protons in the nucleus (atomic number) |
| difference between an element and a compound: | element - made up of the same atom compound - made of up multiple different elements with multiple different atoms |
| the original idea of atoms came from the ________. | greeks |
| true or false: an element (collection of atoms) has different properties than a single atom. | true |
| true or false: atoms are composed of small indivisible, indestructible particles called atoms. | false they can be broken up |
| true or false: all atoms of an element are identical and have the same mass and properties. | false there are isotopes |
| true or false: compounds are formed by combinations of atoms of 2 or more elements. | true this is the definition of a compound |
| which subatomic particle was discovered first? | electron |
| what is the name of JJ Thomson model for the discovery of the electron? | cathode ray tube |
| true or false: the type of metal the cathode was made of did not affect the behavior of the ray. | true |
| particle ray bent toward the ________ plate. | positive |
| what is the evidence from Thomson experiment that all atoms contain electrons? | particles were identical regardless of the metal used for the cathode |
| alpha particle ________ if its same charge as nucleus | deflects (its repelled) |
| Rutherford's experiment showed: | atom is mostly empty space, the small dense positive nucleus in the center of the atom |
| neutrons are slightly ________ than protons | heavier |
| gravity is responsible for ________ between objects that have ________. | attraction, mass |
| electromagnetic force is responsible for ________ or ________ between objects that have electric ________. | attraction, repulsion, charge |
| when is a ball thrown into the air what force(s) are acting on the object as it is in the air? | gravity |
| what happens to the gravitational force of attraction as the mass of the interacting object increases? | the force increases |
| what happens to the gravitational force of attraction as the distance between the interacting objects increases? | the force decreases |
| the force between charges can be modeled by using ________ law. | coulombs |
| if the charge ________ between two objects then the force increases. | increases |
| if ________ distance between objects the force decreases. | increase |
| both interactions of gravitational force and electromagnetic force follow an ________ law. | inverse square |
| if someone has a ball resting on their hand what force(s) are acting on it? | gravitational and electrostatic (gravity pulls it downward (attraction) and electrostatic pushes it upward (repulsion)) |
| changes in energy are caused by changes in ________. | forces |
| system: | part of the universe you are looking at |
| surroundings: | everything else in the universe |
| kinetic energy is the energy associated with ________. | motion |
| a ball is falling down, as the ball moves toward the ground what happens to the KE? | it increases (the ball is accelerating so the velocity increases) |
| potential energy is the energy associated with the ________ of objects in a field. | position of systems |
| when two objects are moving with a force PE ________. | decreases |
| when two objects are moving against a force PE ________. | increases |
| the ball is falling down, as the ball is falling what happens to the total energy of the system? | it remains the same no energy is leaving the system |
| energy can be ________ from one object to another upon collision. | transferred |
| energy can be ________ from PE ---> KE. | transformed |
| properties of a solid: | definite shape and volume, cannot be compressed |
| properties of a liquid: | takes shape of container, can move, definite volume |
| properties of a gas: | can be compressed, no specific shape or volume |
| dipole: | separation of charges within an atom |
| instantaneous dipole: | electron cloud can fluctuate momentarily creating a partial charge that only lasts for a moment. |
| the ________ coulombic interaction causes atoms to approach. | attractive |
| if atoms get to close and the electron clouds overlap then the ________ becomes dominant. | repulsive force |
| when the electron clouds overlap the PE ________. | increases |
| true or false: both gravitational and electrostatic forces are mediated by fields. | true |
| at the potential minimum the system is most ________. the attractive force = the repulsive force. | stable |
| why do atoms approach? (referring to dipoles) | the instantaneous dipole is inducing the neutral atom causing it to form a partial charge. |
| when you change the temp of a system where does the energy come/go? | surroundings by collision |
| what about breaking of an attractive interaction between two atoms is true? | energy is absorbed (breaking requires energy to go into the system) |
| when an element has more electrons is it easier or harder to form a dipole? | easier (the electron cloud is larger, so it is "floppier") |
| does an element with more electrons have a longer or shorter internuclear distance? | longer (it has a bigger electron cloud) |
| what info does the depth of the potential well tell you about the strength of the interaction? | the deeper the potential well the more energy would be required to get the atoms to separate |
| what info does the position of the potential minimum along the x-axis give you? | the distance between the nuclei when the atoms are most stable (internuclear distance) |
| if the potential minimum is farther to the right, will it have a larger or smaller atomic radius? | larger |
| when we remove energy from a system, it takes away from the ________ of the system and creates a _______. | total energy, molecule |
| intermolecular forces compared to bonds: | IMFs - relatively weak, occur between neutral molecules/atoms bonds - stronger, occur within molecules |
| what about forming a chemical bond is true? | energy is released |
| we use the ________ to allow us to connect from the molecular level to the observable macroscopic level. | mole |
| a mole: | 6.022 x 10^23 |
| mass of 1 mol in any substance is its ________ in grams. | formula mass |
| what happens to mass during a chemical reaction? | it remains the same (we are just rearranging, mass is CONSERVED) |
| to convert from mass to moles to mass we use ________. | molar mass |
| what properties ascribed by the Greeks do we still consider valid? | atoms are mostly empty space, and they are in constant motion |
| in the gold foil experiment where will the majority of the alpha particles go? | straight through the atom, because it is mostly empty space |
| true or false: it was found that in the gold foil experiment some of the particles would reflect off in different directions | true |
| what part of Daltons atomic theory did Thomson cathode experiment prove to be false? | all atoms are indivisible and indestructible |
| why was the electron the first subatomic particle to be discovered? | they are on outside of an atom so it is easier to remove them, along with the fact they have a negative charge and easier to detect and can be manipulated by electromagnetic fields |
| description of Thomson's proposed atomic structure: | a positive "sphere" with negative charged embedded in it |
| description of Rutherford's model of the atom: | a positive nucleus with orbits around it containing electrons. |
| what did Rutherford discover? | that there is a positive nucleus within the atom |
| percent yield=________ yield / ________ yield. | actual, theoretical |
| true or false: the limiting reactant is whichever element produces more of the product from its starting amount. | false it is whichever product produces less |
| remaining amount of the excess product = ________ amount - ________ amount. | starting, used |
| what do you use to convert from moles of one molecule to moles of another molecule? | stoichiometric ratio |
| percent yield: the actual amount comes from ________, and the theoretical amount comes from ________. | experiment, calculation |
| electrons can be manipulated by _______ and ________ fields. | electrical, magnetic |
| which property of electromagnetic radiation can be explained with the double slit experiment? | the interference of light, when a beam of light passes through two small slits the two resulting waves interfere with each other |
| if the intensity of green light is increased what changes? | the amplitude of the wave, and the number of photons emitted |
| which experimental parameter could you increase to cause electrons to be ejected from the metal? | the frequency of the light, currently the photons don't have enough energy to overcome the attractive interaction and increasing the frequency would increase the energy of each photon |
| on an energy diagram absorption is represented by an __________ arrow. | upward |
| why are the absorption spectra different for neon and argon? | the differences in energy between energy levels are not the same for neon and argon |
| why must we consider the wave-like properties of an electron but not a larger object? | the wavelength of an electron is similar in size to the electron and therefore affects the properties of the electron |
| would S^2- or Ca^2+ have a smaller ionic radius? | Ca^2+ is smaller because it has more protons pulling on the same number of electrons as in S^2- |
| where would you predict there to be a big jump in the successive ionization energies for oxygen? | between IE 6 and IE 7 because it requires more energy to remove a core electron than to remove a valence electron |
| what evidence supports the claim that all matter and energy in the universe were once concentrated in a single point? | the absorption spectra of galaxies are red shifted because those galaxies are moving away from us |
| when a covalent bond is formed between two hydrogen atoms energy is ________ and a ________ is formed | released, molecule |
| what is an example of nuclear fusion? | two H + one H ----> three He |
| consider the potential energy diagram for two nuclei as they approach each other, when the nuclei are separated by a large distance the potential energy ________, the nuclei ________ each other due to electrostatic interactions. | decreases, repel |
| examples of electromagnetic radiation. | radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays. |
| how do we characterize electromagnetic radiation? | different wave lengths, different frequencies, and different energies. |
| what models are used to describe the behavior of light (electromagnetic radiation)? | wave and particle |
| higher amplitude = ________. | more intense/brighter light. |
| as wavelength changes so does ________. | frequency |
| frequency ________ as wavelength shortens. | increases |
| amplitude: | height of peaks (intensity). |
| wavelength: | distance between two identical points |
| frequency: | number of wave fronts per second |
| wavelength and frequency are related by the ________. | speed of light |
| what is the equation for wavelength and frequency? | speed of light = (wavelength) x (frequency) |
| true or false: energy of light is related to amplitude. | false |
| evidence that light is also a wave is that waves ________ and particles don't. | diffract |
| properties of waves in-phase: | peaks and troughs line up (higher amp/brighter) |
| properties of waves out-of-phase: | peak of one wave lines up with the trough of another wave (cancel out - no amp, dark) |
| what is the relationship between the velocity of the wave, the wavelength, and the frequency? | the velocity of the wave is the speed of light. The relationship is that the speed of light (velocity) = the wavelength times the frequency. |
| which has the longest wavelength: X-rays, visible light, infrared rays | infrared (it has the lowest frequency) |
| true or false: energy increases with intensity. | false amp (intensity) doesn't define energy, frequency does |
| higher frequency light (and shorter wavelength) has ________ energy. | higher |
| what is the evidence that light is also a particle? | the photoelectric effect |
| what is the photoelectric effect? | it is when light hits a piece of metal causing it to release an electron. |
| how does the photoelectric effect work? | the light is transferring energy to the electron(s) at the metal surface where it is transformed into kinetic energy that gives the electron(s) enough energy to "leave" the atoms in the metal. |
| when you increase the intensity of ultraviolet light: | the number of electrons emitted increases |
| you keep the intensity the same and increase the wavelength of the blue light: | no change (but increasing the wavelength does decrease the frequency) |
| you keep the yellow light and increase the intensity: | zero electrons are emitted |
| when light shines on a metal surface the outcome depends on the ________ of the light. | frequency |
| if the frequency of light is above the threshold frequency electrons are _________. | emitted from the metal (creates a current) |
| when the intensity (brightness) of the light is increased ________ electrons are emitted. | more |
| if the frequency of light is below the threshold frequency, will it emit electrons if you increase the intensity? | no, it doesn't matter how intense (bright) the light is electrons are never emitted if the frequency of the light is below the threshold frequency |
| what is the evidence that light is not just a wave that it's also a particle? | if light were just a wave, then increasing the intensity of the light should increase the energy of the light, and with bright enough light of any frequency electrons should be emitted. BUT THIS DOESN'T HAPPEN, because light is also a particle |
| the energy of a photon is ________. | quantized it can only have certain values |
| what is the equation for energy of a photon? | energy of a photon = (planks constant) x (frequency) |
| what is planks constant? | h = 6.626 x 10^ - 34 Js |
| if the photon has enough energy, it can ________. | eject one electron |
| when an atom emits light, we see ________. | strips of color and the rest of the spectrum is dark |
| when an atom absorbs light, we see ________. | strips of dark and the rest is the colorful spectrum. |
| atomic absorption and emission spectra show light only of ________ wavelengths/energies. | specific |
| what is Rutherford's model of the atom? | electrons circling nucleus like planets around the sun |
| does the Rutherford model of the atom explain atomic absorption and emission spectra? | no |
| what is the Bohr's model? | electrons move in orbits around the nucleus, each orbit is bigger than the last and has a higher energy than the last. |
| in Bohr's models the orbits have ________ energies and are at ________distances from the nucleus. | definite, definite |
| Bohr explained emission and absorption spectra be invoking _________ energy levels, characterized by ________ numbers (n). | discreate, quantum |
| in Bohr's model photons are emitted or absorbed by atoms as electrons move from _________. | one energy level to another |
| the energy of the photons corresponds to the ________ in energy between the orbits. | difference |
| if a photon is added its energy must equal: | the difference in energies between orbits |
| what is the problem with Bohr's model? | electrons are moving in defined orbits around nucleus at known energy levels and it only works for hydrogen |
| what is a better way to represent the transition of electrons upon absorption or emitting photons? | energy diagrams |
| which set of transitions would produce an emission spectrum? | atom emitting light, getting rid of energy |
| how are absorption and emission different from the photoelectric effect? | absorb/emit electron is staying within the atom, just moving levels photoelectric: the electron is actually leaving the atom |
| what is the equation for wavelength in terms of matter? | wavelength = (planks constant) divided by (mass) times (velocity) |
| what is the evidence that electrons are waves? | diffraction and interference pattern of waves of light and electrons. |
| true or false: we can't measure accurately both energy and position of an electron and that is why Bohr's model is wrong. | true |
| what must our model of the atom include? | electrons (and all particles at atomic molecular level) have wave-like properties, electrons in an atom can only have certain energies (their energies are quantized) |
| true or false: since we know the energy of the electron, we can't know its exact position. | true |
| Erwin Schrodinger applied quantum mechanics to answer what? | where the electrons are in atoms |
| atomic orbitals: | regions of space where electrons with certain quantized energy have high probability of being found |
| principal quantum number (n): | determines energy of orbital and identifies its shell - the larger the number the higher the energy and the larger the orbital |
| angular momentum quantum number (l): | identifies the type of orbital (s,p,d,f, ...) and subshell |
| magnetic quantum number (m1): | specifies a particular orbital within a subshell (ie the orientation of the orbital) |
| spin quantum number (ms): | determines the spin of the electron |
| true or false: no two electrons in an atom have the same four quantum | true |
| there are ________ orbitals in both the s and p orbitals. | three |
| how many orbitals are in the electron cloud of one atom? | all of the orbitals (s,p,d,etc) overlap within the electron cloud |
| the 4s orbital is ________ energy than 3d orbital. | lower |
| electrons can be described by orbitals of _______ shapes and ________ energies. | different, definite (this allows us to understand how elements bond and react and the arrangement of the periodic table) |
| we often refer to elements by the location of their electrons in the ________ orbitals. | outermost (valence electrons) |
| atomic radius: | half the distance between the two nuclei when two atoms are reacting through LDF's |
| what determines the size of an atom | the balance between the attractions of the protons and electrons, and repulsions between the electrons in the atom. (the nucleus pulls electrons in and the repulsions between the electrons push the electrons outward) |
| explain why the atomic radius decreases across the row on the periodic table. | the number of protons and electrons increases. the valence electrons are shielded from full charge of nucleus by core electrons. so, the electrons repel each other and push the electron cloud out. |
| coulomb's law explains: | both attractions between protons and electrons and repulsions between the electrons |
| the atomic radius represents the state where the forces of ________ between electrons and protons are equal to the forces of ________ between electrons. | attraction, repulsion |
| effective nuclear charge: | every valance electron is attracted by the ENC |
| core electrons ________ the positive charge from the same number of protons as there are core electrons. | cancel out |
| if the effective nuclear charge increases then the force _______. | increases |
| Columb's law equation for effective nuclear charge: | electrostatic attraction (F) = k (charge of val electron) x (ENC) divided by (distance between the valance electron and the nucleus) |
| as you go across a row ENC ________. | stays the same, attractive force is not different but more electrons lead to more repulsions and a larger AR |
| ions are atoms in which ________ have been added/removed. | electrons |
| cations are ________ charged. | positively |
| anions are ________ charged. | negatively |
| ionization energy: | energy required to remove an electron from an atom in the gas phase |
| trends down a group: | AR increases, IE decreases |
| trends across a row: | AR decreases, IE increases |
| smaller atoms have ________ ionization energies. | higher |
| the trends in radius and IE are ________ related. | inversely, but both caused by ENC |
| true or false: it is easier to remove a lone electron from a p orbital than a lone electron from a s orbital. | true, a p orbital is a little farther away from the nucleus than an electron in the s orbital |
| everything in the universe is moving ________ from us with increasing speed. | away |
| doppler effect: | wavelength depends on what the observer is doing |
| if an object emitting light is moving away from us which direction will the wavelength of the light be shifted? | toward the red end of the spectrum (to longer wavelengths) |
| when the __________ takes over the interaction between the nuclei becomes attractive, the PE falls and energy is released into the surroundings. | strong nuclear force |
| what is the evidence that the big bang occurred? | the universe is expanding (red shift) |
| isotopes have the ________ number of protons and ________ number of neutrons. | same, different |
| fusion: | adding two nuclei together |
| fission: | breaking a nucleus apart |
| at ________ nuclear fusion can occur | very high temperatures |
| in order for fusion to occur what has to happen? | two nuclei have to collide (this is difficult because they have the same charge, that's why it must be at a very high temperature) |
| strong nuclear force holds ___________. | everything together in the nucleus |
| in order for the SNF to come into play the nuclei have to get as close as a distance of about the ________. | diameter of nucleus |
| when the SNF comes into play what happens to the PE of the system? | decreases (SNF becomes dominant, so they are working with the force) |
| nuclear reactions are accomplished by changes in ________. | mass |
| during nuclear reactions mass is converted into ________. | energy |
| mass defect: | mass loss (the pieces of isotope don't equal the same as the atom) |
| mass loss is converted into _______. | binding energy |
| why don't we use fusion reactors instead of combustion (fossil fuels)? | it takes a LOT of energy to start fusion reaction and we haven't managed to get as much energy back out as we put in to start fusion |
| true or false: fission is the opposite of fusion | false, although it is the opposite because it's breaking the nucleus while fusion is adding two together, they both RELEASE energy. |
| nuclear fission: | fragmentation of heavy nuclei to form lighter more stable ones and energy is released |
| critical mass: | mass of the isotope required for the chain reaction to become self-sustaining |
| ________ nuclei undergo fusion to become stable and release energy. | light weight |
| ________ nuclei undergo fission to become more stable and release energy. | heavier |
| radioactivity: | nucleus emits or captures particles of energy in the form of electromagnetic radiation |
| what atoms were formed immediately following the big bang? | H, He, Li |
| atomic radius decreases from left to right across a row on the periodic table because? | the relative attraction between the protons and the outer electrons increases. |
| how do we support the idea that electron energies are quantized? | IEs are constant and replicable for any given electron means that this amount of energy must be added to the atom to eject the electron |
| what happens to the system when a molecular substance boils? | energy is absorbed into the system and interactions between the molecules are overcome |
| what is the best explanation for why metals are shiny? | when a photon of light is absorbed in a piece of metal an electron is promoted to a higher energy molecular orbital. When the electron drops back into the lower energy level a photon is emitted. |
| according to valance bond theory how do bonds form between carbon atoms in graphite? | three sp2 hybrid orbitals on each atom overlap end-to-end while the unhybridized p orbitals overlap side-to-side |
| equation for formal charge: | formal charge= valence electrons - number of bonds on central atom - number of lone pair on central atom |
| it is easy to rotate around a single bond because the overlap between the ________ orbitals involved in the bond doesn't change upon rotation. | hybrid |
| why is liquid water more dense than solid water? | channels of empty space form in the solid state but not in the liquid state due to hydrogen bonding between water molecules |
| emergent properties belong to a collection of atoms but not what? | the indicidual components |
| the properties of the products of a chemical reaction are ________. | emergent |
| we ________ predict the properties of a product from the properties of the reactants. | can't they are unrelated |
| the properties of any substance depend on the ________ that exist within that substance. | bonding/interactions |
| the difference between the electrostatic attraction of LDF's and covalent bonds is ________. | the magnitude of the attraction |
| in a covalent bond the ________ is the most stable distance between atoms (ionization energy is lowest potential energy). | bond length |
| when bonds form energy is ________ to the ________. | released, surroundings |
| molecular orbital theory - | electrons are waves and can therefore combine constructively and destructively |
| in molecular orbital theory ________ combine to give ________. | n molecular orbitals, n molecular orbitals |
| when atomic orbitals combine ________ bonding molecular orbitals form. | constructively |
| bonding molecular orbitals are _________ energy than the atomic orbitals. | lower |
| when atomic orbitals combine ________ antibonding molecular orbitals form. | destructively |
| antibonding orbitals are ________ energy than the atomic orbitals. | higher |
| molecular orbitals can also only hold ________. | two electrons |
| by combining atoms, the energy of the system ________ to become more stable | decreases |
| two electrons in a bonding orbital make ________. | one bond |
| two electrons in a bonding molecular orbital are ________ but two electrons in an antibonding molecular orbital would ________ the stabilization. | stabilizing, cancel out |
| to break the bond, enough energy has to be ________ to raise an electron to the antibonding orbital. | added |
| what happens to the molecule when the electron is promoted to the antibonding orbital? | the bond holding the molecule together was broken because it now is unstable |
| what are the properties of metals? | shiny, conduct electricity and heat, malleable and ductile |
| as the number of molecular orbitals increases the energy gap between them ________. | decreases |
| electrons can move ________ over the whole system. | freely |
| because atoms can move with respect to one another metals are ________. | malleable and ductile |
| because electrons can move around freely metals _______. | conduct electricity |
| when melting or boiling where are the attracting that are being overcome? | between particles |
| the temperature of the phase change tells you about the ________ of interaction you are overcoming. | strength |
| what are the allotropes in carbon? | diamond and graphite |
| properties of diamond: | high mp, hard, brittle, translucent, does not conduct electricity |
| properties of graphite: | high mp, soft, slippery, grey, shiny, conducts electricity |
| we explain why diamond and graphite have different properties through _______. | bonding |
| each carbon atoms forms 4 bonds to 4 identical carbon atoms; we call this geometry a ________. | tetrahedral |
| to explain the bonding in carbon we need to use a different model of bonding known as ________. | valance bond theory |
| in the valence bond theory model, we assume that the atomic orbitals ________ to form bonds. | overlap |
| where the atomic orbitals overlap is where you find the ________. | valance electrons |
| details of valence bond: | atomic orbitals overlap to form a bond the greater the overlap the stronger the bond each bond is made up of two electrons electrons are localized in the bond |
| how can carbon form 4 identical bonds in diamond? | it uses 4 hybrid orbitals |
| what type of bonds exist between metals at room temp? | metallic bonds |
| sp3 hybrid orbitals are called ________ bonds. | sigma |
| sigma bonds form when atomic orbitals overlap ________. | end-to-end |
| in graphite in one sheet how many carbon atoms is each carbon atom attached to? | three |
| bonding in graphite is one _________ and two ________. | s orbital, p orbitals |
| the bonding in graphite makes a geometry called ________. | trigonal planar |
| a C-C-C bond is ________ degrees. | 120 degrees |
| is a sp2 bond there is a ________ left over. | p orbital |
| side to side overlap of atomic orbitals gives you a ________. | pi bond |
| what is the information missing from a Lewis structure? | the shape of the molecule |
| structural ________ have the same formula, but different connectivity. (Therefore, different properties) | isomers |
| how are isomers the same and different? | same - number of each type of atom, chemical formula different - connectivity between atoms, properties |
| what happens when a molecular substance boils? | forces BETWEEN molecules are overcome |
| single bonds allow ________ rotation. | free |
| true or false: you can't rotate around double bonds because it would break the pi bond. | true |
| alkenes contain ________ double bond. | C-C |
| what hybridized orbitals are used to form a double bond? | sp2 |
| double bonds contain: | one sigma bond and one pi bond |
| triple bonds consist of ________ and ________. | one sigma bond, two pi bonds |
| the valence shell electron pair repulsion helps figure out the ________ of the molecules from the Lewis structure. | shape |
| lone pairs, single bonds, double bonds, triple bonds each count as ________ center. | one |
| 2 electron centers are a _________ geometry with ________ hybridization. | linear, sp 180-degree bond angle |
| three centers make up a ________ geometry with ________ hybridization. | trigonal planar, sp2 120-degree bond angle |
| four centers make up a ________ geometry with ________ hybridization. | tetrahedral, sp3 109-degree bond angle |
| electron center geometry is ________ always same as the molecular shape. | NOT |
| to calculate the ENC: | number of protons minus number of core electrons |
| electronegativity: | ability of an element to attract electrons to itself in a bond |
| true or false: noble gases are not electronegative because they don't form bonds. | true |
| electronegativity depends on ________ and ________. | ENC, size of orbitals |
| when electrons are not shared equally this results in a ________ we say the bond is ________. | dipole, polar |
| dipole-dipole interactions are present in ________ substances. | polar |
| what effect would increasing molecular polarity have on strength of the IMF? | it would increase |
| hydrogen bonding interactions are ________. | IMF's |
| H-bond must contain H covalently bonded to either _______. | N, O, or F |
| the N, O, or F must contain a _______ and this atom has a large ________. | lone pair, negative dipole |
| compounds with H-bonding also have ________ and ________. | dipole-dipole, LDF's |
| where does the energy come from when breaking an interaction? | other molecules and atoms in the surroundings transferred when molecules collide |
| bent shape: | contains three molecules where one has a lone pair |
| trigonal planar shape: | contains four molecules with 3 bonds around the central atom and no lone pairs |
| trigonal pyramidal shape: | contains four molecules with three bonds and a lone pair around the central atom |
| linear shape: | contains three atoms which two bonds around the central atom and no lone pairs |
| if a molecule has no lone pairs around the central atom, then the ________ is the same as the geometry. | shape |
| you can tell which H-bond would take more energy to separate based on what information? | which one has more hydrogen bonds in it |
| H-bonds are limited by the number of ________ to ________ ratio. | hydrogen, lone pair |
| unlike diamond graphite can conduct electricity because? | in graphite there are unhybridized p-orbitals that extend over the entire sheet forming a delocalized pi bonding network where electrons are free to move |
| what types of bonding would be present in a molecule with a high mp that does not conduct electricity? | there is covalent bonding within the molecules and LDF's between the molecules |
| dipole-dipole interactions are stronger than LDF's due to the presence of ________. | permanent dipoles |
| the way atoms interact depends on the ________. | arrangement of electrons |
| when 2 atoms interact with: 1s2 2s2 2p4, how many molecular orbitals are generated? | 10 you have one 1s orbital plus one 2s orbital plus THREE 2p orbitals (don't forget there are three 2p orbitals) so that's 5 and you have 2 atoms so 5 time 2 is 10 |
| ion-ion interactions are ________ bonds. | not |
| simple ionic compounds contain a ________ and a ________. | metal, nonmetal |
| in simple ionic compounds the metal has low electronegativity, and the non-metal has high electronegativity the metals form ________ and the non-metals form ________. | cations, anions |
| ionic compounds are ________ and NOT molecules. | neutral |
| complex ionic compounds contain a ________. | polyatomic ion |
| a polyatomic ion is a group of atoms ________ bonded to each other and the entire particle has a _______. | covalentley, charge |
| metals _______ electrons. | loose |
| transition metals always form _______ cation. | 2+ |
| ion-ion interactions are electrostatic attractions the force of attraction between ions: more charge ________, smaller ions ________. | stronger attraction, stronger attraction |
| energy is released when an ionic lattice ________ from ions in gas phase. | forms |
| stronger attraction = greater ________ energy. | lattice |
| ionic compounds exist as _________ lattices, not isolated cations and anion pairs. | countinueous |
| what are the charged particles in salt? | ions |
| in which state are ions free to move? | liquid |
| 0 degrees Celsius = _______ Kelvin | 273.15 |
| 0 K is ________ zero | absolute |
| temperature tells you in which direction ________ energy will move. | thermal |
| energy always moves from the ________ object to the ________ object. | hotter, cooler |
| thermal energy depends on ________ material you have. | how much |
| temperature is directly related to the ________ of the particles. | average KE |
| at a given temp do all atoms in a gas move at the same speed? | no |
| populations of molecules have a temp where: KE ave= ________. | 3/2kT |
| k is the ________. | Boltzmann constant |
| if the temp increases the average velocity ________, and the average KE increases. | increases (because 1/2mvavg^2=3/2kT) |
| if the molar mass of the gas increases what happens to the average velocity? | decreases the temp isn't changing so the velocity must decrease |
| types of energy of motion: | translation, rotation, vibration |
| thermal energy: | energy associated with motion of particles |
| heat: | transfer of thermal energy from one place to another |
| specific heat: | energy required to raise 1g by 1 degree celcius |
| we can ________ the heat from the temp change using specific heat/heat capacity. | quantify |
| molar heat capacity: | energy required to raise 1 mol by 1-degree Celsius |
| what happens to temp during a phase change? | it doesn't change thermal energy is used to overcome the interactions |
| open system: | can transfer energy and matter |
| closed system: | transfer energy but not matter |
| isolated system: | no transfer of energy of matter |
| change in energy equation: | change in energy= energy final minus energy initial |
| transferred energy: | energy from one thing to another |
| transformed energy: | changes the type of energy |
| q represents the thermal energy ________. | change |
| w is the ________ done. | work |
| if energy is going into the system its ________ and if energy is going out its ________. | positive, negative |
| q and w are ________ functions it matters how much the change occurs. | path |
| enthalpy change H= _____ | q |
| enthalpy (h) is heat absorbed/emitted during a process under constant ________. | pressure |
| if change in H is positive the process is ________. if change in H is negative the process is ________. | endothermic exothermic |
| if the same amount of energy is added to different substances which one would reach the highest temp? | the one with the lower heat capacity, its easiest to increase |
| when energy is added what happens at the molecular level? | the KE increases making things move faster |
| a human is a _______ system. | closed |
| something with the highest lattice energy with have a smaller ________ and so stronger force. | radius |
| when gas molecules collide why don't they stick together? | they have enough energy to overcome interactions |
| what if the gas molecules collide at very low temps? will they stick together then? | yes, they don't have enough energy to overcome the attractive forces |
| change of H melting is equal to the ________ change of H freezing. | negative |
| change of H vaporization is equal to the _________ change of H condensation. | negative |
| you can predict relative magnitudes of heats for phase change from __________ structures. | molecular |
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