Quiz (01.15.2021) Flashcards
we define the ___ as the material or process within which we are studying the energy changes within
system
we define the ____ as everything else with which the system can exchange energy
surroundings
a ____ is the amount of energy needed to move 1kg mass a distance of 1 meter
joule (J)
A _____ is the amount of energy needed to raise the temperature of one gram of water 1C
calorie (cal)
kcal =
energy needed to raise 1000g of water 1C, Calories = kcal
____ is the study of energy and its interconversions
thermodynamics
the ___ energy is the sum of the kinetic and potential energies of all the particles that compose the system
internal
the change in the internal energy of a system only depends on…
the amount of energy in the system at the beginning and end
A ___ function is a mathematical function whose result only depends on the initial and final conditions not on the process used
state
when energy flows out of a system, change in energy in the system is ___
negative
when energy flows into the surroundings, change in energy in the surroundings is ___
positive
when energy flows into a system, change in energy in the system is ___
positive
when energy flows out of the surroundings, change in energy of the surroundings is ____
negative
energy is exchanged between the system and its surroundings through ___ and ___
heat; work
q and w are NOT state functions, their value depends on the process. change in energy =
q + w (heat plus work)
the heat capacity of an object is proportional to the following:
the mass, the specific heat of the material
q =
mass (g) x specific heat capacity x temperature change (C)
measure of a substance’s intrinsic ability to absorb heat
specific heat capacity - the amount of heat energy required to riase the temperature of one gram of a substance 1C
Units for specific heat capacity
J/gxC
The ___ is the amount of heat energy required to raise the temperature of one mole of a substance 1C
molar heat capacity
Pressure-volume work is work caused by …
a volume change against an external pressure
when gases exchange, change in volume is positive, but the system is doing work on the surroundings, so work of the gas is ___
negative
as long as the external pressure is kept constant, work of the gas equals…
external pressure x change in volume of the gas
conversion factor for 1 atm x L to Joules
1 atm x L equals 101.3 J
system gains thermal energy, q (heat) is ___
positive
system loses thermal energy, q (heat) is ___
negative
work done on the system, w (work) is ____
positive
work done by the system, w (work) is ____
negative
energy flows into the system, change in internal energy is____
positive
energy flows out of the system, change in internal energy is ____
negative
amount in joules (J) required to raise temperature of 1g of water by 1C
4.18
amount in calories (cal) required to raise temperature of 1g of water by 1C
1.00
amount in Calories (C) required to raise temperature of 1g of water by 1C
0.00100
amount in kilowatt-hour (KWh) required to raise temperature of 1g of water by 1C
1.16 x 10^-6
the ___ of a system is the sum of the internal energy of the system and the product of pressure and volume - it is a state function
enthalpy
what is the equation for enthalpy?
H = E + PV
the enthalpy change of a reaction is…
the heat evolved in a reaction at constant pressure
change in enthalpy of the reaction
the heat of the reaction at constant pressure
usually change in enthalpy and change in energy are similar in value; the difference is largest for reactions that produce or use…
large quantities of gas
when change in enthalpy is negative…
heat is being released by the system
when heat is being released by the system, it is an ____ reaction
exothermic
when change in enthalpy is positive…
heat is being absorbed by the system
when heat is being absorbed by the sysrem, it is called an _____ reaction
endothermic
for an exothermic reaction, the surrounding’s temperature ___
rises
the products of an exothermic reaction have ___ chemical potential energy than the reactants
less
in an endothermic reaction, the surrounding’s temperature ____
drops
Products in an endothermic reaction have ____ chemical potential energy than the reactants.
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