General Chemistry Chapter 7: Thermochemistry Flashcards Preview

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Flashcards in General Chemistry Chapter 7: Thermochemistry Deck (24)
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1

Isolated systems

exchange neither matter nor energy with the environment

2

Closed systems

exchange energy, but not matter with the environment

3

Open systems

exchange both energy and matter with the environment

4

Isothermal processes

Occur at a constant temperature

5

Adiabatic processes

exchange no heat with the environment

6

Isobaric processes

occur at a constant pressure

7

Isovolumetric (isochoric)

occur at a constant volume

8

State functions

describe the physical properties of an equilibrium state; they are pathway independent and include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy and entropy

9

Standard conditions

defined as 298 K, 1 atm and 1 M concentrations

10

Standard state

It's most prevalent from under standard conditions; standard enthalpy, standard entropy and standard free energy are all calculated under standard conditions.

11

At temperatures about the critical point:

liquid and gas phases are indistinguishable.

12

Triple point

All three phases of matter exist in equilibrium

13

Phase diagram

graphs the phases and phase equilibria as a function of temperature and pressure

14

Temperature

a scaled measure of the average kinetic energy of a substance

15

Heat

The transfer of energy that results from differences of temperature between two substances.

16

Enthalpy

The measure of the potential energy of a system found in intermolecular attractions and chemical bonds

17

Hess's law

states that the total change in potential energy of a system is equal to the changes of potential energies of the individual steps of the process

18

Entropy

While often though of as disorder, it is a measure of the degree to which energy has been spread throughout a system or between a system and its surroundings

19

What is the units for Entropy?

heat transferred per mole per unit K

20

When in entropy maximized?

at equilibrium

21

G

reaction proceeds forward (spontaneous)

22

G = 0

reaction is in dynamic equilibrium

23

G > 0

reaction proceeds in reverse direction (nonspontaneous)

24

What does Gibbs depend on?

temperature; can change between spontaneous and non-spontaneous based on temp.