Kategorier: Alle - reaction - medicine - cooking

af Visvanathan Sanjeev 2 år siden

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Thermochemistry and Rates of reactions Concept map

Understanding thermochemistry and reaction rates is essential for enhancing our knowledge of chemical systems and improving daily life. In cooking, the concept explains why cookies bake faster at higher temperatures due to the increased rate of chemical reactions.

Thermochemistry and Rates of reactions Concept map

Thermochemistry and Rates of Reactions Concept Map

Chemical Kinetics

enhances our knowledge on the systems around us and improve quality of life
Usage in Medicine

the concentration over time

Some take a lot longer to reach equilibrium

how serious the condition is

reaction takes longer to fight off pathogens

Some medications work close to instantaneously

used to predict dosage use

Higher dose would work faster (greater concentration)

Adults due to developed body types

Kids would take a low dose due to undeveloped systems --> rate of reaction occurs fast with low dose

Advil

Tylenol

the affect of medications on different people's bodies

the best drug for different diseases

Usage in everyday life

Cooking

baking cookies

Cookies bake faster at higher temperature

Faster rate of chemical reaction

Cleaning Items

How different products have their own effect

Different products react on different surfaces and clean specific things

Counter cleaners, toilet cleaners etc.

React differently to get rid of unwanted substances as fast as possible

Unique to their own property

the study of ways to make chemical reactions go slower or faster
Theoretical effects

Affects on collision theory

Presence of catalyst

Provides alternate pathway

Larger fractions of collisions are effective

Rise in temperature

Causes particles to move and react faster according to particle theory

Chances of collisions increases

Increase in surface area

Gives more room for volume

Effective collisions

Increase in concentration

Increases rate of reaction

Higher concentration = more particles in volume which increases the likelyhood of effective collisions

Nature of chemical substances reacting

Bonds to be broken

effective collisions

Chemical nature of reactant

Maxwell Boltzmann distribution

distribution of speeds among particles at a given temperature

Represents different energies

Number of molecules with certain kinetic energy

threshold energy

the minimum kinetic energy required to convert kinetic energy to activation energy

Energy of collisions

More frequent and effective collisions

formation of the activated complex

Collison Theory

Help determine reaction rates

reaction mechanism

elementary steps

steps in a reaction mechanism that only involves 1, 2, or 3 particles collisions

reaction intermediate

a substance that is formed during reaction and consumed when the reaction is complete

rate-determining step

slowest step in reaction mechanism

having the highest activation energy

activation energy

low activation energy

more particles with sufficient energy required to reach the transition state

high activation energy

fewer particles with sufficient energy required to reach the transition state

minimum energy required for particles to collide and rearrange in structure

the difference in energy between the reactant and the transition state

the sequence of two or more simple reactions that continue to form the overall reaction

frequency of collisions and the fraction of those collision

rate = frequency of collision x fraction of collisions that are effective

Fraction effective

Heterogenous

Reactants and Catalysts in different physical states

Homogenous

Reactants and Catalysts are in the same state

nature of reactant

Collision Frequency

concentration

surface area

particles must collide

each other or the walls of the container

ineffective Collisions

colliding particles rebound

unchanged in nature

Effective Collisions

colliding particles has sufficient energy and collide in correct orientation

break bonds and form new bonds

transition state or activated complex

Always is higher in energy than products and reactants

Particles are in constant random motion at various speeds in a chemical reaction

kinetic energy of particles

the temperature of the sample

rate of reaction

Appearance of products

Disappearence of reactant

catalyst

a substance that is mostly used to speed up rate of reaction

being consumed itself

temperature

temperature decrease

temperature increase

Surface area

surface area of reactant in a hetrogeneous system is increased

Concentration of reactants

initial concentration is decrease

reaction rate decreases

initial concentration is increase

reaction rate increases

Chemical nature of reactants

similar elements (in the same group) react similar

gold and silver

react slow in air

instaneous rate of reaction

the speed of the reaction at a particular point in time

average rate of reaction

the speed of the reaction over a period of time

Change in concentration per unit time

r = Δc/Δt

mol L-1 s-1

the rate at which the reactant is consume over a time interval

the rate at which the product is formed

Hess's Law

Human body when we exercise and burn calories
the amount of calories burned during a workout

track individual progress and meet their optimal shape

Car companies when building an engine
how much energy the car engine uses or produces when it burns fuel

determine efficiency of an engine

Calculating change in enthalpy using Hess's law
Law of additivity of reaction enthalpies
Germain Hess, a Swiss Chemist
Calculate state functions
Change in Entropy
change in Gibb's energy
Change in Enthalpy

ΔHtarget = ΣΔHknown

Alter ΔH in the same way

the coefficients of a chemical equation is altered

multiplying or dividing by a constant factor

Reverse sign of ΔH

Chemical equations is reversed

the change in enthalpy of the targeted reaction
the sum of the change of enthalpy for each separate step to get to the targeted reaction