Experiment 11 - Calorimetry: Heats of Neutralization

To calculate heat capacity, we need to assume

1. Any thermal energy from the calorimeter to the outside environment is negligible 2. All dilutes, aq solutions have the same density (1.00g/mL) and specific heat as water (4.184 J/g degrees celsius)

Endothermic reaction

A reaction that ABSORBS energy in the form of heat

Exothermic Reaction

A reaction that releases energy in the form of heat

Heat of Neutralization

An enthalpy change Happens when equivalent amount of acid and base are mixed together to form 1 mole of water

adiabatic calorimeter

Do not allow the transfer of heat or matter between a thermodynamic system and it's surroundings

Flow of thermal energy measuring

Done by the change in Temperature

first law of thermodynamics

Energy cannot be created or destroyed Conservation of Energy

Units for Energy

Joules (J) or kg m2/s2

state function

Knowing only the state in which you got it Don't know anything of the state before or after your data was taken

Goal of the Experiment

Measure the heat or enthalpy of neutralization when an acid and a base react to form a salt and water in a calorimeter

Determining heat capacity of calorimeter or calorimeter constant

Measuring heat absorbed by the calorimeter

Assumption of the calorimeter

No loss of heat to surroundings

Organic Acid Qualities

Partially dissociate in aqueous solution, energy is required to break the bond between the proton and its conjugate base, lower ΔH

Standard enthalpy for organic acids

Standard enthalpy of strong acids and strong bases is higher than those of organic acids

What will you be measuring before and after mixing reactants

Temperature Initial and Final

Heat Capacity of the calorimeter

The amount of heat (J) required to raise the temperature by 1 Kelvin, which is the same as raising the temperature by 1 degree Celsius.

Enthalpy

The heat content of a system at constant pressure

Calorimetry

The precise measurement of heat flow out of a system for chemical and physical processes Technique used to measure thermal energy changes in chemical reaction ex. the door open. let heat go out into the cool air. making it colder in the room

Heat

Thermal energy flowing from an object at higher temperature to one at lower temperature

neutralization reaction

a reaction in which an acid and a base react in an aqueous solution to produce a salt and water

Energy changes lead to

chemical reactions (in the form of thermal energy/heat) ex.Heat loss when a door is open

Neutralization reaction liberates/releases

heat and increase temperature in the solution in the calorimeter

When an acid and base are mixed in solution, the heat of reaction Equation

q = m x C x ΔT q = heat energy gained or lost m = mass of water C= specific heat capacity ΔT = temperature change of the reaction mixture

heat capacity

the amount of heat needed to increase the temperature of an object exactly 1°C The energy needed to increase the temperature of a certain mass by exactly 1°C

Temperature change

the change in the particles movement speed. cold = slow moving particles warm = fast moving particles

specific heat capacity

the energy required to raise the temperature of one gram of a substance by one degree Celsius

The heat of a reaction

the enthalpy change for a chemical reaction

Calorimeter

thermally insulated vessel

Change in Enthalpy

ΔH

Reaction is carried on by CONSTANT PRESSURE, measurements made by calorimeter gives you

ΔH (kJ/mole) directly of the reactant and the product

Heat absorbed, endothermic reaction

ΔH < 0 ; heat is absorbed

Heat evolved, exothermic reaction

ΔH < 0 ; heat is released

Standard Enthalpy change

ΔH = q/n ΔH = enthalpy change q = heat energy gained or lost n = number of moles