AP Chemistry Unit 6

The First law of Thermodynamics state (blank)

states can neither be created nor destroyed, it can only transfer or change forms.

Collisions between molecules will results in a transfer of their (blank), called (blank)

• Kinetic energy

• Heat Exchange

The more energetic particles will (blank) and the less energetic ones will (blank)

• slow down

• speed up

(blank); both samples will be at the same temperature, so their particles will have the same avg KE and net flow of heat will stop

Thermal equilibrium

In an (blank) process, heat is released from the system into the surroundings. The system gets (blank) and it’s surroundings get (blank)

• Exothermic

• cooler

• warmer

In an (blank) process, heat is absorbed by the system from the surroundings; the system gets (blank) and the surroundings get (blank)

• endothermic

• warmer

• cooler

Many Chemical reactions will absorb or release. called (blank)

Enthalpy

Enthalpy is associated with breaking or forming (blank) or (blank)

Chemical bonds or IMFs

Forming bonds or IMFs is (blank)

exothermic

Breaking bonds or IMFs is (blank)

endothermic

ΔH > 0

more energy is absorbed to break the bonds than released by forming bonds (endothermic)

The change or ΔH is the grand (blank)

total for all the bonds broken and formed in a reaction

ΔH < 0

If more energy is released by forming bonds than is absorbed to break bonds (exothermic)

You’ll feel warm near an (blank) reactions and cold near (blank) reactions

• Exothermic

• Endothermic

Exothermic Energy Profile

Endothermic Energy Diagram

A catalyst speeds up a reaction by providing the reactants with an (blank)

Alternate pathway

Enthalpy of formation is the (blank) in energy that takes plance when one mole of a compound is formed from its (blank) under standard state conditions

• change

• component pure elements

Enthalpy of formation equation

ΔH = ΔHproducts - ΔHreactants

Substances with (blank) are more stable than their elements

ΔH < 0

Combustion is always an (blank) process

exothermic

When a bond is formed, energy (blank) to the bond energy is released

equal

Bond energy equation

ΔH = Bonds Broken - Bonds formed

Hess’s Law Rules

1. if you flip the equation, flip the sign

2. if you multiply or divide, also do that for the enthalpy value

3. several equations when summed up make a new equation

Hydration energy is always (blank)

negative

Hydrogen bonding stretches out the IMFs make it a (blank)

Endothermic process

Ion-dipole forces form between seperated ions and water, making a (blank)

Exothermic Process

Phase changes change only the (blank)

Physical properties

A change in heat can change the (blank) or (blank) but not both

• temperature

• phase

Heat or enthalpy of transition is the (blank) associated with the changing phase of a compound

change in enthalpy

IMFs are strongest in the (blank)

solid phase

Enthanly of fusion is the energy that must (blank) to break those IMFs

• absorbed (ΔH > 0)

• Freeze is the (ΔH < 0)

The enthalpy of vaporization is the amount of heat associated with (blank)

• vaporizing (ΔH > 0)

• Condense (ΔH < 0)

Enthalpy of Subliminate is used to (blank) or (blank)

• Solid to Gas (ΔH > 0)

• Gas to Solid (ΔH < 0)

Enthalpy of fusion is the energy that is put into a solid to (blank)

Melt it

Enthalpy of vaporization is the energy that must be put into a liquid to (blank)

turn it into a gas

An Object with a larger specific heat can absorb a lot without (blank)

undergoing a large temperature change

Calorimetry Equation

q = mcΔT

Calorimetry experiments measure change in (blank) associated with some (blank)

• temperature

• chemical reaction

Solid to Liquid

Melting or fusion

Liquid to solid

Freezing

Liquid to gas

Vaporization

Gas to Liquid

Condensation

Solid to gas

Sublimation

Gas to solid

Deposition

Label each one

• A-B Solid

• B-C melting

• C-D liquid

• D-E boiling

• E-F Gas

A longer plateau means a larger (blank)

heat of transition

Substances with lower specific heats have (blank) since they require less heat to change their temperature

greater slopes

The intermolecular forces within a solid are more (blank) and therefore have (blank) than the forces within a liquid

• stable

• lower energy

When substance is changing phases, the temperature of that substance remains (blank)

constant