General Chemistry 7: Thermochemistry

Standard conditions are [...] K, [...] atm, [...] M

273 k

1 atm

1 M

[...] is the phase change from solid to liquid

Fusion

• also known as melting

[...] is the phase change from liquid to solid

freezing

[...] is the phase change from liquid to gas

vaporization

[...] is the phase change from solid to gas

sublimation

[...] is the phase change from gas to solid

deposition

label the phases in the phase diagram

The point in phase diagram where all 3 phases exist is known as the [...]

triple point

A/an [...] fluid is one in which the density of gas = density of liquid

supercritical

• no distinction between those two phases

[...] combines enthalpy and entropy into a single value and is used to determine the spontaneity of a reaction

Gibbs free energy

• we only concerned with changes in G, rather than its absolute value

• gibbs free energy = (change enthalpy) - (temperature X change in entropy)

If a reaction has a positive ∆H and positive ∆S, then it will be [spontaneous or nonspontaneous] at [high, low, or all] temperatures

spontaneous at high temperatures

If a reaction has a positive ∆H and negative ∆S, then it will be [spontaneous or non-spontaneous] at [high, low, or all] temperatures

non-spinatanours at all temperatures

If a reaction has a negative ∆H and positive ∆S, then it will be [spontaneous or non-spontaneous] at [high, low, or all] temperatures

spontaneous at all temperatures

If a reaction has a negative ∆H and negative ∆S, then it will be [spontaneous or non-spontaneous] at [high, low, or all] temperatures

spontaneous at low temp

Room temperature is approximately [...] Celsius

25

25 c= 75 f

Body temperature is approximately [...] Celsius

37 c to 98.6 f

[...] is a measure of the potential energy of a system found in intermolecular attractions and chemical bonds

enthalpy (H)

Phase changes from solid → liquid → gas are [endothermic or exothermic]

endothermic

• gasse have more heat energy than liquids and liquids have more heat energy than solids

Phase changes from gas → liquid → solid are [endothermic or exothermic]

exothermic

• these reactions release heat energy

Give the formula for ∆H when using heat of formations

Give the formula for ∆H when using bond dissociation energies

[...] is a measure of how much energy has spread out or how spread out energy has become

entropy

Give the formula for the standard entropy of reaction

Give the Gibbs Free Energy equation that uses the equilibrium constant K_eq

Give the Gibbs Free Energy equations that use the reaction quotient Q

If ∆G < O, the reaction will be [...]

spontaneous

If ∆G = O, the reaction will be

at equilibrium

If ∆G > O, the reaction will be [...]

non-spontaneous