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