Chemistry IV

Law of Conservation of Mass

In a chemical reaction, the total mass of

the substances before and after the

reaction remains the same.

It can neither be created nor destroyed but it can rearrange.

Reactants

The substances which undergoes chemical reactions.

Products

The substances which are the end products of a chemical reaction

Activation Energy

The minimum amount of energy that is required to activate molecules or atoms so that they can undergo chemical transformation.

React with

In chemical reaction or equation, what does + read as?

Yield / Produces

In chemical reaction or equation, what does → read as?

Decomposition

Synthesis

Single-replacement

Double-replacement

Combustion Reaction

Composed of fuel/organic compound, air, heat, and water.

e.g. CH4 + 2O2 → CO2 + 2H2O

Neutralization Reaction

Formed by an acid base.

e.g. NaOH + HClO3 → NaCl + H2O

Rate of reaction

The speed at which reactants are converted into products.

Nature of reaction

The rate of reaction highly depends on the type and ______. Few reactions are naturally faster than others while some reactions are very slow. (Fastest to slowest: Gas, liquid, solid — because it has more space/ readily avaliable)

Collision theory

According to the ______, the rate of reaction increases with the increase in the concentration of the reactants.

Law of mass action

The chemical reaction rate is directly proportional to the concentration of reactants.

Concentration of reactants

This implies that the chemical reaction rate increases with the increase in concentration and decreases with the decrease in the concentration of reactants.

1.) Collisions should be effective.

2.) The right orientation of reactant molecules towards each other.

3.) All molecules should possess a minimum amount of energy

The conditions for the collisions to form products are?

Pressure factor

Pressure increases the concentration of gases which in turn results in the increase of the rate of reaction.

Temperature

According to collision theory, a chemical reaction that takes place at a higher temperature generates more energy than a reaction at a lower temperature. This is because colliding particles will have the required activation energy at high temperature and more successful collisions will take place.

Solvent

Much soluble ____ leads to higher rate of reaction.

Electromagnetic radiation

Form of energy (lights) and its presence at the chemical reaction may increase the rate of reaction as it gives the particles of reactants more energy.

Presence of catalyst

Substance that increases the rate of the reaction without actually participating in the reaction. Providing an alternate pathway which has lower activation energy

Surface area

Exposed parts

Rate law

The ____ expresses the relationship of the rate of a reaction to the rate constant and the concentration of the reactants raised to the same powers.

Kinetics

Refers to the study of how things move and how those movements are caused by forces.

Rate = M/s

Rate law equation.

Reaction order

The ____ provides an indication of how changing the concentration of the reactant will affect the reaction's speed.

First order

If the rate doubles

Second order

If the rate quadruples

Zero order

When nothing happened to the rate

Negative 1 order

When the rate is divided into half or slows down

Overall reaction

The sum of individual order

Thermodynamics

Is an extensive scientific discipline that deals with the interconversion of heat and other forms of energy.

First law of thermodynamics

It states that energy cannot be created nor destroyed; It can only be converted from one form to another.

2nd law of thermodynamics: Entropy

States that energy naturally spreads out or becomes more disordered over time, and heat always flows from something hotter to something cooler, not the other way around— unless you use extra energy to make it happen.

Energy spreads out, and things tend to get
messier or more disorganized unless you do work to keep them ordered.

More entropy

More energy dispersal means …

Favorable

Increasing the Entropy of a system, is thermodynamically.

3rd law of thermodynamics

It says that as something gets colder and colder—closer to absolute zero—it loses all disorder (entropy) and becomes perfectly organized.

All molecular motion would stop, and the substance would have no more energy to give off.

Entropy = S(J/K)

Entropy equation

True

Entropy is not a measure of energy itself, but how energy is distributed within a system. (True or False)

Enthalpy

Internal energy of a system.

Gibbs Free Energy

is a way to tell whether a chemical reaction or physical process can happen on its own (spontaneously) under constant temperature and pressure.

Chemical energy budget

Gibbs free energy is like a “_____” that tells us if a reaction is worth doing.

can happen spontaneously

If ΔG < 0 (negative), the process…

won’t happen spontaneously

If ΔG > 0 (positive), the process…

Equilibrium

If ΔG = 0, the system is at…

Always spontaneous

If ΔG is negative it is

Never spontaneous

If ΔG is positive it is

Energetically favorable

If ΔH is negative it is

Energetically unfavorable

If ΔH is positive it is

Entropically unfavorable

If ΔS is negative it is

Entropically favorable

If ΔS is positive it is