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CHEM 1211 Chap 6, 7, 8.4
Test 3
69
Chemistry
Undergraduate 2
03/27/2012

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Term
first law of thermodynamics
Definition
_____________ states that when energy is exchanged or transformed the energy is still there. The total amount of energy in the universe before the change has to equal the total after.
Term
internal energy E
Definition
The _________  is the total amount of kinetic and potential energy a system possesses.
Term

a. The change in the system's internal energy

b. heat (thermal energy)

c. work energy (transfer of energy)

Definition

ΔE = q + w

Δ E represents a._______

q represents b.______

w represents c.______

Term
Work
Definition
  • Is any activity that requires energy
  • Is done when you do any physical activity
  • Defined as the force applied over a distance and is characterized by a transfer of energy
Term
Energy
Definition
  • Is a component of almost everything we do. Makes objects move, stop
  • Can be exchanged between objects through contact, collisions
  • Can also be transformed from one form to another heat → light → sound
Term

Law of conservation of energy

created nor destroyed

Definition
______________- energy can be converted from one form to another, but can never be ______ nor ______, only transferred
Term
Thermodynamics
Definition
The study of energy is called _________. It studies the exchange of energy between the system and the surroundings.
Term
joule (J)
Definition
One _____ is the amount of energy needed to move a 1-kg mass a distance of 1 meter.
Term
calorie (cal)
Definition
One ______ is the amount of energy needed to raise one gram of water by 1 degrees C
Term
system, surroundings
Definition
Transfer of Energy is defined in terms of _______ and ________
Term
system
Definition
The ______ is defined as the material or process that contains the energy changes we are studying.
Term
surroundings
Definition
The __________ are defined as everything else in the universe.
Term
beginning and end
Definition
The ΔE of a system depends only on the amount of energy in the system at the ____________, not the transfer.
Term

+

Endothermic

Definition

If energy is added ΔE = 

Heat flow is into a system, Absorb energy from the surroundings

Term

-

Exothermic

Definition

If energy is removed ΔE = 

Heat flows out of the system, Releases energy to the surroundings

Term
positive
Definition

Endothermic Process:

Heat (q) is

Term
negative
Definition

Exothermic Process:

Heat (q) is

Term
heat exchange (q) or work (w)
Definition
________ is exchanged between the system and surroundings through either _________ or _______ being done.
Term
heat
Definition
______ involves the transfer of energy between two objects due to a temp. diff.
Term
negative
Definition
System does work on surroundings w is
Term
positive
Definition
Surroundings do work on the system w is
Term
q (heat) and w (work)
Definition
Energy is a state function, but ___ and ___ are NOT state functions, their values depends on the process
Term
specific heat Cs units J/(g.C)
Definition
The ________ capacity is the amount of heat energy required to raise the temp of one gram of a substance 1 degree C
Term
molar heat
Definition
The ________ capacity is the amount of heat energy required to raise the temp of one mole of a substance 1 degree C
Term
Specific Heat Capacity
Definition
The measure of a substance's intrinsic ability to absorb heat.
Term
q = (m) x (Cs) x (ΔT)
Definition
We can calculate the quantity of heat absorbed by an object with the formula
Term
postive, negative
Definition
When gases expand, ΔV is _____, but the system is doing work on the surroundings (exerting a pressure), so wgas is ____.
Term

external pressure • change in vol.

w = -PΔV

Definition

As long as the external pressure is kept constant, work of a "gas" can be calculated using this formula.

-work = 

Term
101.3J = 1 atm • L
Definition
To convert the normal units for work (joules) to fit the formula w = -PΔV, use ______
Term

qsystem

or q = ΔE + 0

b/c work = 0 if there is no change in vol.

Definition

At constant volume, ΔEsystem =

(usually measured in kJ/mol of substance) 

Term
enthalpy, H
Definition
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
Term
ΔH = ΔE + ΔPV    P is constant
Definition
The formula to measure the energy of a reaction, in terms of heat, when volume can not be constant.
Term
enthalpy change, ΔH
Definition
The _________ of a reaction is the heat evolved in a reaction at constant pressure.
Term
ΔHreaction = qreaction at constant pressure
Definition
The formula for the change in enthalpy of a reaction at constant pressure is
Term

ΔE + PΔV = q

 

q

Definition

at constant pressure

ΔH = _________

at constant volume

ΔE = _

Term
heat
Definition
Energy needed for a chemical reaction is absorbed or released as ______.
Term
heat of reaction (ΔH)
Definition
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.
Term
ΔH = ΔHproducts - ΔHreactants
Definition
The formula to calculate the heat of reaction (ΔH) is
Term
endothermic
Definition
In an __________ reaction, the energy of the products is greater than the energy of the reactants, heat is absorbed (+)
Term
exothermic
Definition
In an ________ reaction, the energy of the products is less than the energy of the reactants, heat is released (-)
Term
the same whether the rxn happens in one or multiple steps.
Definition
Hess's Law states in going from a particular set of reactants to a particular set of products, ΔH is...
Term
the sum of the heats of reaction for each step.
Definition
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...
Term

ΔHrxn =

[cΔHf (C) + dΔHf (D)] - [aΔH(A) + bΔHf (B)]

Definition

a A + b B → c C + d D

ΔHrxn = ∑ n ΔHf (products) - ∑ n ΔHf (reactants)

Write out what the equation would be using letters.

Term

standard states

 

zero

Definition
Elements in their _________ are not included in the ΔHrxn calculations b/c ΔHf for an element like this is _____.
Term
Electromagnetic radiation
Definition
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.
Term
wavelength (λ) 
Definition

distance between two peaks or troughs in a wave.

units is m or nm,etc

Term
frequency (v)
Definition

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

Term
3.00 x 108 m/s
Definition
Speed (c) of light =
Term
c = λ v
Definition
To calculate the way energy travels through space is.
Term
wavelength or frequency
Definition
The color of light is determined by its ________ or _________.
Term
lowest to highest (RIVUX G)
Definition
The electromagnetic spectrum arranges all forms of light energy from _____ to _____.
Term
longest to shortest
Definition
The electromagnetic spectrum arranges energy from _______ to ______ wavelengths.
Term
varying energies
Definition
Different atoms have varying amounts of electrons with...
Term
quantized
Definition
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.
Term
photons
Definition
Electromagnetic radiation in atoms is a stream of "particles/e-" called...
Term

Ephoton = hv = hc

                        λ

Definition
How we relate energy of an atoms electrons to the electrons frequency, speed, wavelength is by using the formula...
Term

The model only works for hydrogen.

Electrons do not actually move around the nucleus in circular orbits/pathways

Definition
Bohr's model does correctly fit the idea of quantized energy levels. However this model is not totally correct b/c?
Term
Heisenberg uncertainty principle
Definition
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.
Term
randomly...so...we can not predict at any one moment where exactly the electron will be.
Definition
An electron is always moving _______ so...
Term
orbital
Definition
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.
Term
quantum numbers
Definition
The size, shape, and orientation in space of an electrons orbital is determined by 3 integer terms called...
Term
principal
Definition
______ 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.
Term
angular momentum
Definition
________ 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
Term
magnetic
Definition
_________ 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)
Term
Electron spin
Definition
___________ quantum number (ms) - can be +1/2 or -1/2. Refers to "spin" orientation of electrons.
Term
increase
Definition
Energy of electrons _______ as they get further from nucleus.
Term
s
Definition
__ orbital has a spherical shape around the nucleus. Each principal energy state (n) has this orbital. Lowest energy orbital in a principal energy state.
Term
Pauli exclusion
Definition
_________  principle - states that in a given atom no two electrons can have the same set of four quantum numbers. (due to repulsions)
Term
two
Definition
Each orbital (ml) can hold only ____ electrons, and they must have opposite spins. (to decrease repulsion)
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