Thermodynamics

Thermochemistry

Energy basics

Heat

Kinetic Energy: Energy of an object in motion.

defining calorimetry

collect data using a calorimeter

Law of conservation of Energy: Energy cannot be created or destroyed, only changed from one form to another.

Thermochemistry

Enthalpy

Hess' law

Chemical reactions and thermochemistry

Units of energy

Joules

calories

Equations

Changes in state

Heat

Temperature: a measure of the average kinetic energy of the particles in a sample

Specific Heat

the amount of heat required to raise 1 g of the substance by 1°C.

Examples of energy

Electromagnetic

Thermal

Exothermic & Endothermic

I calorie = 4.2 Joules (water)

Nuclear

chemical

Potential Energy: Stored energy gained by an objects position in relation to its surroundings.

Calorie: food calorie. Kilocalorie. 1000 calorie= 1 Calorie

specific heat of water is 4.2 J/g x *C

Coffee cup calorimeter

bomb calorimeter

Heat content of a system at constant pressure

Cannot be directly measured but we can measure the change in enthalpy during a reaction

Exothermic: A reaction that releases heat energy

solid, liquid, gas, plasma

Endothermic: A reaction that takes in heat energy

DH= Hproducts-Hreactants. DH= Hfinal-Hinitial

enthalpy for exothermic reactions are always negative. For endothermic reactions, its always positive.

light

heat

The process of measuring how much heat is absorbed or released during a reaction or process.

Colorimeter: an insulated device used for measuring the amount of heat absorbed

System: specific part of the universe that contains the reaction or process you wish to study

q=(m)(c)(DT)

Surroundings: everything in the universe except the system

Activation energy: difference between the energy needed to form the activated complex and the energy of the reactants

Specific heat of water is very important. Water requires a lot of energy to heat and a lot of time for it to change in temperature. Important for life (Ocean).

click to edit

states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.

click to edit