thermochemistry Flashcards
concerned with heat changes that occur during chemical reactions
thermochemistry
the science of the relationship between heat and other forms of energy
thermodynamics
-the capacity of doing work or supplying heat
-weightless, odorless, tasteless
-if within the chemical substances, it is called chemical potential energy
energy
characteristics of energy
weightless, odorless, tasteless
if within the chemical substances, energy is called what
chemical potential energy
Three Broad concepts of energy
kinetic energy, potential energy, internal energy
energy associated with an object by virtue of its motion
kinetic energy
energy an object has by virtue of its position in a field of force
potential energy
the sum of the kinetic and potential energies of the particles making up a substance
internal energy
states that in any chemical or physical process, energy is neither created nor destroyed
Law of Conservation of Energy
all the ___ is accounted for as work, stored energy, or heat
energy
All the energy is accounted for as what
work, stored energy, heat
the total energy of a system is the sum of its kinetic energy, potential energy, and internal energy
U
represented by q, is energy that transfers from one object to another because of a temperature difference between them
heat
only changes can be detected
heat
flows from warmer to cooler objects
heat
in studying heat changes, think of defining these 2 parts
The system, the surroundings
the part of the universe on which you focus your attention
the system
includes everything else in the universe
the surroundings
heat flowing out of a system into its surroundings
exothermic process
-defined as negative
-q has a negative value
-called exothermic
-system loses heat (gets cooler) as the surroundings heat up
exothermic process
heat flowing into a system from its surroundings
endothermic process
-defined as positive
-q has a positive value
-called endothermic
-system gains heat (gets warmer) as the surroundings cool down
endothermic process
the quantity of heat needed to raise the temperature of 1g of pur water to 1 degree celsius
calorie
also related to the Joule, the SI unit of heat and energy
calorie
1 cal is equivalent to
4.184J
1g
calorie
1kg
Calorie
the amount of heat needed to increase the temperature of an object exactly 1 degree celsius
heat capacity
depends on both the object’s mass and its chemical composition
heat capacity
the amount of heat it takes to raise the temperature of 1g of a substance by 1 degree celsius
specific heat capacity
specific heat capacity is abbreviated by
C
Specific heat capacity is often called simply
specific heat
types of thermochemical equations
exothermic reaction, endothermic reaction
the products are lower in energy than the reactants. thus, energy is released
exothermic reaction
the products are higher in energy than the reactants. thus, energy is absorbed
endothermic reaction
the symbol is H
enthalpy
change in enthalpy is what
∆H
if heat is released, the heat of the content of the product is lower
exothermic (delta H is negative)
if heat is absorbed, the heat content of the products is higher
endothermic (delta H is positive)
the measurement of heat into or out of a system for chemical and physical processes
calorimetry
heat released is equals to what
the heat absorbed
calorimetry is measured using what
calorimeter
absorption or release of heat in chemical or physical processes
calorimetry
