CHEM 1211 Chap 6, 7, 8.4 – Flashcards
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| Energy |
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Law of conservation of energy created nor destroyed |
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| ______________- energy can be converted from one form to another, but can never be ______ nor ______, only transferred |
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| Thermodynamics |
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| The study of energy is called _________. It studies the exchange of energy between the system and the surroundings. |
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| joule (J) |
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| One _____ is the amount of energy needed to move a 1-kg mass a distance of 1 meter. |
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| calorie (cal) |
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| One ______ is the amount of energy needed to raise one gram of water by 1 degrees C |
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| system, surroundings |
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| Transfer of Energy is defined in terms of _______ and ________ |
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| system |
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| The ______ is defined as the material or process that contains the energy changes we are studying. |
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| surroundings |
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| The __________ are defined as everything else in the universe. |
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| beginning and end |
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| The ?E of a system depends only on the amount of energy in the system at the ____________, not the transfer. |
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+ Endothermic |
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If energy is added ?E = Heat flow is into a system, Absorb energy from the surroundings |
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- Exothermic |
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If energy is removed ?E = Heat flows out of the system, Releases energy to the surroundings |
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| positive |
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Endothermic Process: Heat (q) is |
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| negative |
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Exothermic Process: Heat (q) is |
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| heat exchange (q) or work (w) |
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| ________ is exchanged between the system and surroundings through either _________ or _______ being done. |
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| heat |
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| ______ involves the transfer of energy between two objects due to a temp. diff. |
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| negative |
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| System does work on surroundings w is |
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| positive |
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| Surroundings do work on the system w is |
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| q (heat) and w (work) |
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| Energy is a state function, but ___ and ___ are NOT state functions, their values depends on the process |
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| specific heat Cs units J/(g.C) |
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| The ________ capacity is the amount of heat energy required to raise the temp of one gram of a substance 1 degree C |
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| molar heat |
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| The ________ capacity is the amount of heat energy required to raise the temp of one mole of a substance 1 degree C |
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| Specific Heat Capacity |
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| The measure of a substance's intrinsic ability to absorb heat. |
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| q = (m) x (Cs) x (ΔT) |
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| We can calculate the quantity of heat absorbed by an object with the formula |
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| postive, negative |
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| When gases expand, ΔV is _____, but the system is doing work on the surroundings (exerting a pressure), so wgas is ____. |
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external pressure • change in vol. w = -PΔV |
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As long as the external pressure is kept constant, work of a "gas" can be calculated using this formula. -work = |
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| 101.3J = 1 atm • L |
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| To convert the normal units for work (joules) to fit the formula w = -PΔV, use ______ |
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qsystem or q = ΔE + 0 b/c work = 0 if there is no change in vol. |
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At constant volume, ΔEsystem = (usually measured in kJ/mol of substance) |
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| enthalpy, H |
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| The _______ of a system is the sum of the internal energy of the system and the product of pressure and volume. Is a state function |
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| ΔH = ΔE + ΔPV P is constant |
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| The formula to measure the energy of a reaction, in terms of heat, when volume can not be constant. |
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| enthalpy change, ΔH |
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| The _________ of a reaction is the heat evolved in a reaction at constant pressure. |
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| ΔHreaction = qreaction at constant pressure |
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| The formula for the change in enthalpy of a reaction at constant pressure is |
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ΔE + PΔV = q
q |
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at constant pressure ΔH = _________ at constant volume ΔE = _ |
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| heat |
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| Energy needed for a chemical reaction is absorbed or released as ______. |
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| heat of reaction (ΔH) |
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| The _______ is the amount of heat absorbed or released during a rxn, and is the diff. in the energy of the products and the reactants. |
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| ΔH = ΔHproducts - ΔHreactants |
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| The formula to calculate the heat of reaction (ΔH) is |
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| endothermic |
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| In an __________ reaction, the energy of the products is greater than the energy of the reactants, heat is absorbed (+) |
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| exothermic |
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| In an ________ reaction, the energy of the products is less than the energy of the reactants, heat is released (-) |
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| the same whether the rxn happens in one or multiple steps. |
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| Hess's Law states in going from a particular set of reactants to a particular set of products,;;H is... |
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| the sum of the heats of reaction for each step. |
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| Hess's Law also states that if a reaction can be expressed as a series of steps, then the ΔHrxn for the overal reaction is... |
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ΔHrxn = [cΔHf (C) + dΔHf (D)] - [aΔHf (A) + bΔHf (B)] |
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a A + b B → c C + d D ΔHrxn = ∑ n ΔHf (products) - ∑ n ΔHf (reactants) Write out what the equation would be using letters. |
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standard states
zero |
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| Elements in their _________ are not included in the ΔHrxn calculations b/c ΔHf for an element like this is _____. |
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| Electromagnetic radiation |
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| Describes energy of light in terms of wavelength and frequency. Moves at speed of light in a vacuum. Energy that travels as waves through space. |
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| wavelength (λ) |
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distance between two peaks or troughs in a wave. units is m or nm,etc |
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| frequency (v) |
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number of waves (cycles) per sec. that pass a given point in space. units are hertz (Hz) or cycles/s = sec-1 1 Hz = 1 sec-1 |
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| 3.00 x 108 m/s |
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| Speed (c) of light = |
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| c = λ v |
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| To calculate the way energy travels through space is. |
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| wavelength or frequency |
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| The color of light is determined by its ________ or _________. |
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| lowest to highest (RIVUX G) |
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| The electromagnetic spectrum arranges all forms of light energy from _____ to _____. |
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| longest to shortest |
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| The electromagnetic spectrum arranges energy from _______ to ______ wavelengths. |
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| varying energies |
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| Different atoms have varying amounts of electrons with... |
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| quantized |
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| When an atom is heated up and the energy passed through a prism, the "spectrum" of colors is NOT continuous. Instead energy of an electron is __________. Meaning each "color" corresponds to the energy of each electron in the atom. |
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| photons |
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| Electromagnetic radiation in atoms is a stream of "particles/e-" called... |
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Ephoton = hv = hc λ |
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| How we relate energy of an atoms electrons to the electrons frequency, speed, wavelength is by using the formula... |
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The model only works for hydrogen. Electrons do not actually move around the nucleus in circular orbits/pathways |
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| Bohr's model does correctly fit the idea of quantized energy levels. However this model is not totally correct b/c? |
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| Heisenberg uncertainty principle |
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| Which principle states that... there is a fundamental limitation to just how precisely we can know both the position and momentum of an electron at a given time. |
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| randomly...so...we can not predict at any one moment where exactly the electron will be. |
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| An electron is always moving _______ so... |
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| orbital |
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| There is a "probability" of where an electron may be at a particular moment. This "probable" space we call an ________. A 3-D e- density map. |
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| quantum numbers |
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| The size, shape, and orientation in space of an electrons orbital is determined by 3 integer terms called... |
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| principal |
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| ______ quantum number (n) - describes size and energy level or orbitals (distance of e- from nucleus). Has integral values of 1,2,3... The larger the value of n, the more energy the orbital has. |
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| angular momentum |
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| ________ quantum number (l) - shape of atomic orbitals (sometimes called a subshell). Shape of orbital usually referred to w/ a letter (s,p,d, or f) and has integral values of 0 to n-1 |
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| magnetic |
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| _________ quantum number (ml);- orientation of the orbital in space relative to the other orbitals in the atom. Has integral values of -l to l (including 0) |
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| Electron spin |
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| ___________ quantum number (ms) - can be +1/2 or -1/2. Refers to "spin" orientation of electrons. |
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| increase |
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| Energy of electrons _______ as they get further from nucleus. |
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| s |
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| __ orbital has a spherical shape around the nucleus. Each principal energy state (n) has this orbital. Lowest energy orbital in a principal energy state. |
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| Pauli exclusion |
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| _________ ;principle - states that in a given atom no two electrons can have the same set of four quantum numbers. (due to repulsions) |
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| two |
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| Each orbital (ml) can hold only ____ electrons, and they must have opposite spins. (to decrease repulsion) |
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