Chemistry 15

^Hrxn =

= Hproducts - Hreactants

q =

= mc^T

potential and kinetic

Energy exists in two forms: __________ and __________ energy.

negative

Enthalpy changes for exothermic reactions are always _________.

negative

If the sign of the free energy change of the system is ________, the reaction is spontaneous.

calorie (cal)

In the metric system of units, the amount of heat required to raise the temperature of one gram of pure WATER by one degree Celsius is defined as a _____________.

system

In thermochemistry, the _________ is the specific part of the universe that contains the reaction process you wish to study.

entropy

In thermodynamics, the term for disorder is _______.

4.184 J

One calorie equals _.___ J.

joule (J)

The SI unit of heat and energy is the _________.

law of conservation of energy

The ___ __ ____________ __ _________ states that in any chemical reaction or physical process, energy can be converted from one form to another, but it is neither created nor destroyed.

Calorie

The nutritional _________ is capitalized.

enthalpy (heat) of formation (^Hf)

The standard _________ (____) __ _________ is defined as the change in enthalpy that accompanies the formation of one mole of the COMPOUND in its standard state from its consistent ELEMENTS in their standard states.

law of disorder (?) second law of thermodynamics

The tendency toward increased entropy is summarized in the ____ ___ ___________ which states that spontaneous processes always proceed in such a way that the entropy of the universe increases.

universe

Therefore, the _________ is defined as the system plus the surroundings.

The flow of heat is reversed. Heat flows from the surroundings to the system.

What happens in an endothermic reaction or process?

rises

When the cooler object absorbs heat, its temperature _____.

decreases

When the warmer object loses heat, its temperature _________.

heat ; warmer to a cooler

____, which is represented by the symbol q, is energy that is in the process of flowing from a _________ __ _ ________ object.

Enthalpy (H)

___________ is the heat content of a system at constant pressure.

spontaneous process

a physical or chemical change that once begun, occurs with no outside intervention.

spontaneous processes (m)

a physical or chemical change without outside intervention

enthalpy (m)

a system's heat content at constant pressure

calorimeter (m)

an insulated device measuring the heat absorbed or released during a chemical or physical process

surroundings (m = matching)

everything in the universe other than the system

c

specific heat of the substance

law of conservation of energy (m)

states that energy cannot be created or destroyed

joule (m)

the SI unit of heat and energy

energy

the ability to do work or produce heat

enthalpy (heat) of combustion (m)

the enthalpy change for the complete burning of one mole a substance

1000 calories or 1 kilocalorie

1 Calorie equals ____ __________ or ___ ________

^Ssystem =

= Sproducts - Sreactants

calorimeter

A _________ is an insulated device used for measuring the amount of heat absorbed or released during a chemical or physical process.

thermochemical equation

A _______________________ ___________ is a balanced chemical equation that includes the physical states of all reactants and products and the energy change, usually expressed as the change of enthalpy ^H.

endothermic

An ____________ reaction is one in which energy is absorbed.

exothermic

An ____________ reaction is one in which energy is released.

product ; reactant

Assuming no change in physical state, the entropy of a system usually INCREASES when the number of gaseous _________ particles is GREATER than the number of gaseous ________ particles.

gained by the water ; lost by the metal

Assuming no heat is lost to the surroundings, the heat _________ by the ______ is equal to the heat ____ by the _____.

high

Because of its ____ specific heat, water can absorb and release large quantities of heat.

positive

Because vaporizing a liquid and melting a solid are ENDOTHERMIC processes, their ^H values are _____________.

solid to a liquid ; liquid to a gas

Entropy INCREASES as a substance changes from a ______ to a _____ ; a ______ to a ___.

surroundings

Everything in the universe other than the system is considered the _____________.

Gibb's Free Energy (Gsystem)

For reactions or processes that take place at constant pressure and temperature, ____'s ____ _________, commonly called free energy, is energy that is available to do work.

one kilocalorie (kcal)

One nutritional Calorie equals 1000 calories or one _______________.

specific heat

The ______ ____ of any substance is the amount of heat required to raise the temperature of one gram of that substance by one degree Celsius.

enthalpy (heat) of combustion (^Hcomb)

The _______ (____) __ __________ of a substance is the enthalpy change for the complete burning of one mole of a substance.

enthalpy (heat) of reaction (^Hrxn)

The change in enthalpy for a reaction is called the ________ (____) of reaction.

chemical potential energy

The energy stored in a substance because of its composition is called ________ __________ ______.

increases

The entropy of any substance INCREASES as its temperature ___________.

molar enthalpy (heat) of fusion (^Hfus)

The heat required to melt one mole of a solid substance is called its ______ __________ (____) __ _______________.

molar enthalpy (heat) of vaporization (^Hvap)

The heat required to vaporize one mole of a liquid is called its ______ __________ (____) __ _______________.

Hess's law

______'s ____ states that if you can add two or more thermochemical equations to produce a final equation for a reaction, then the sum of the enthalpy changes for the individual reaction is the enthalpy change for the final reaction.

Entropy (s)

___________ is a measure of the number of possible ways that the energy of a system can be distributed and this is related to the freedom of the system's particles to move and number of ways they can be arranged.

Thermochemistry

_______________ is the study of heat changes that accompany chemical reactions and phase changes.

Thermochemical Equation (ws)

a balanced chemical equation that includes the physical states of all reactants and products and specifies the change in enthalpy

thermochemical equation (m)

a balanced chemical equation that includes the physical states of all reactants and products and the energy change that accompanies the reaction

Heat (ws)

a form of energy that flows from a warmer object to a cooler object

Entropy (ws)

a measure of the disorder or randomness of the particles of a system

Spontaneous Process (ws)

a physical or chemical change that occurs without outside intervention and may require energy to be supplied to begin the process

Calorimeter (ws)

an insulated device that is used to measure the amount of heat released or absorbed during a physical or chemical process

Enthalpy of Reaction (ws)

change in enthalpy for a reaction--- difference between the enthalpy of the substances that exist at the end of the reasction and the enthalpy of the substances present at the start

^T

change in temperature in degrees Celsius (Tf -Ti)

potential energy

energy due to the composition or position of an object

heat (m)

energy flowing from a warmer to a cooler object

kinetic energy

energy of motion

molar enthalpy (heat) of fusion (m)

energy required to melt one mole of a solid

molar enthalpy (heat) of vaporization (m)

energy required to vaporize one mole of a liquid

chemical potential energy (m)

energy stored in a substance because of its composition

free energy (m)

energy that is available to do work

standard enthalpy (heat) of formation (m)

enthalpy change occuring when one mole of a compound in its standard state forms from its constituent elements in their standard states

a car

ex. of a quick burn

digestion

ex. of a slow burn

q

heat absorbed or released

specific heat (m)

heat required to raise the temperature of one gram of a substance by one degree Celsius

Hess's Law (ws)

if thermochemical equations can be added to produce a final equation for a reaction, the sum of the enthalpy changes for the reactions is the enthalpy change for the final reaction

Surroundings (ws)

in thermochemistry, includes everything in the universe except the system

System (ws)

in thermochemistry, the specific part of the universe containing the reaction or process being studied

Universe (ws)

in thermochemistry, the system plus the surroudings

m

mass of the sample in grams

Law of Disorder (ws)

states that entropy of the universe must increase as a result of a spontaneous reaction or process

second law of thermodynamics (m)

states that spontaneous processes always proceed in such a way that the entropy of the universe increases

energy (m)

the ability to do work or produce heat

calorie (ws)

the amount heat required to raise the temperature of one gram of pure water by one degree Celsius

Molar Enthalpy of Vaporization (ws)

the amount of heat required to evaporate one mole of a liquid

Molar Enthalpy of Fusion (ws)

the amount of heat required to melt one mole of a solid substance

Specific Heat (ws)

the amount of heat required to raise the temperature of one gram of a given substance by one degree Celsius

energy (ws)

the capacity to do work or produce heat; may be potential or kinetic

enthalpy (heat) of reaction (m)

the change in enthalpy in a chemical reaction

Enthalpy of Combustion (ws)

the enthalpy change for the complete burning of one mole of a given substance

Enthalpy (ws = word search)

the heat content of a system at constant pressure

thermochemistry (m)

the study of heat changes from chemical reactions and phase changes

Thermochemistry (ws)

the study of heat changes that accompany chemical reactions and phase changes

universe (m)

the system plus the surroundings