Chem Quiz over energy

Law of Conservation of Energy

energy can neither be created or destroyed, it can only be transformed from one form to another

Energy

The capacity of a system to do work or transfer heat

Kinetic energy

The energy form that can object or a particle has by reason of its motion

Example(s) of Kinetic energy

Movement of water molecules in a hot cup of coffee. Falling objects, moving cars, or flowing rivers.

Temperature

A measure of the average kinetic energy or molecules in the systems

Potential energy

The store energy within a system due to its position, structure, or the arrangement of its atoms and molecules.

Example(s) of Potential energy

A drawn bow, water stored in a dam, a rollercoaster at the top, or a compressed spring.

Chemical (potential) energy

The stored energy within the chemical bonds of a substance

Example(s) of Chemical (potential) energy

Batteries, food, gasoline, and explosives

Thermal energy

The energy contained within a system that is responsible for its temperature; high particle motion due to its heat

Heat

Transfer of thermal energy between two objects or systems at different temperatures

Example(s) of Heat

Heating water on a stove.

Specific Heat (c)

The amount of energy needed to increase the temperature of one gram of a substance by 1 degrees Celcius

Specific Heat (c)

A substance’s resistance to changes in temperature

Change in Temperature

Final temp minus initial temp

Specific heat of water (H2O)

4.18 J/g *C

Kilojoule

J x 1KJ/ 1000J = -2.88 KJ

q in MCat

heat

m in MCat

mass

c in MCat

specific heat capacity

ΔT in MCat

Change in temperature

Calorimeter

fa cg styrofoam cup- lets no heat in or out

Step 1 in Calorimetry

Start with H2O and find q (J/energy of H2O)

Step 2 in Calorimetry

Flip sign of the J/energy of H2O and solve for the specific heat of the metal

Characteristics of solids

Vibrate, “no spacing”- as compact as possible, low kinetic energy

Characteristics of liquids

flow, very small spacing, medium-low kinetic energy

Characteristics of gases

Constant random motion, very big spacing, HIGH kinetic energy

Condensation

Gas to liquid

Vaporization

Liquid to gas

Deposition

Gas to solid

Solidification

Liquid to solid

Liquification

Solid to liquid

Sublimation

Solid to gas

EntHalpy

the total energy content of a system

Exothermic enthalpy

Rxn where MORE energy is relation by new bonds forming than was consumed breaking the original bonds

Exothermic enthalpy ________ energy

releases

Endothermic enthalpy

Rxn where LESS energy is relation by new bonds forming than was consumed breaking the original bonds

Endothermic enthalpy ________ energy

Takes in

System

The object being observed

Surroundings

Everything else around the object

Universe

EVERYTHING (system and surroundings)

Heat of Rxn (ΔHrxn)

The energy lost or gained during a rxn

Heat of formation (ΔHf)

The energy lost or gained when 1 mol of a chemical is formed from its ground state (by itself with no charge) element

How to solve enthalpy

ΔH = H(products) - H(reactants)

Exothermic

Endothermic

Convection

Heat transfer in fluids

Hot fluids ______ in convection

rise

Cold fluids ______ in convection

sink

Radiation

energy transfer through photons

Conduction

energy transfer through direct contact (fast vibrating particles)