Types of chemical reactions, rate of chemical reaction and chemical equilibrium Flashcards
What is a physical reaction?
Change in the state of matter. The identity and composition do not change
What is a chemical change?
Change in the chemical composition. The structure of substances change
What are the 2 parts of a chemical reaction?
REACTANT(s) give you a PRODUCT(S)
What happens in a chemical reaction?
The bonds between atoms in the reactants are broken, and atoms arerearranged & new bonds are formed
What is an indication that a chemical reaction has taken place?
new properties become visible e.g., change in colour, formation of a gas (bubbles), formation of a solid (precipitate), heat (or a flame) produced of heat absorbed.
What does a small triangle above the arrow in a chemical reaction mean?
reactants are heated.
What does (aq) in a chemical reaction mean?
Aqueous
Can matter be created or destroyed in a chemical reaction?
No, The Law of Conservation of Matter states that matter cannot be
created or destroyed during a chemical reaction.
What is a combustion reaction?
- Combustion reactions are the most common type of chemical reaction.
- A Combustion reaction is a chemical reaction between a substance and oxygen (usually from air) that proceeds with the evolution of heat and light (usually from a flame)
What is a redox reaction?
In a Redox reaction, electrons are transferred from one substance to
another. If one substance loses electrons, another substance must gain electrons
What does OIL stand for?
Oxidation Is Loss of electrons
What does RIG stand for?
Reduction Is Gain of electrons
What is the oxidizing agent (substance reduced)
Electron(s) gained
WHat is the reducing agent (substance oxidized)
Electron(s) lost
What are the Three Conditions Required for a Reaction to Occur
- Collision The reactants must collide.
- Orientation The reactants must align properly to break and form
bonds. - Energy The collision must provide the energy of activation.
What is the nature of reactants?
-Reactions between ions in aqueous solution are very fast (activation energies are very low).
- Reactions between covalent compounds, whether in water or another solvent, are slower (their activation energies are higher).
What does concentration mean?
- In most cases, the reaction rate increases when the concentration of either or both reactants increases.
What are the Factors That Influence Chemical Reaction Rate
- Temperature: An approximate rule for many reactions is that for a 10°C increase in temperature, the reaction rate doubles. When temperature increases, molecules move faster (they have more kinetic energy), which means that they collide more frequently. More frequent collisions mean higher reaction rates.
- increase in reactant Concentration
- Chemical Kinetics/ Activation energy: Rubbing a match head against a rough surface provides the activation energy needed for a match to ignite.
- Increase in state of subdivision
- Addition of a catalyst.
What is a reversible reaction?
A reaction that can be made to go in either direction
What is chemical equilibrium?
The state in which forward and reverse chemical reactions occur simultaneously at the same rate
The concentrations of reactants and products no longer change (but do not have to be equal)
What is Le Châtelier’s Principle of equilibrium?
If a stress is applied to a system in equilibrium, the system will readjust in the direction that best reduces the stress imposed on the system
If more products have been produced as a result of the disruption, the equilibrium is said to have shifted to the right
When disruption causes more reactants to form, the equilibrium has shifted to the left
What are the three changes that affect the equilibrium system?
- Concentration changes - The system will shift in the direction that consumes some of the added component, and if a component is removed, the opposite effect occurs
- Temperature - Keq will change depending upon the temperature. In endothermic reactions, energy is a reactant, and in exothermic reactions, energy is a product
- Addition of catalysts - Do not change the position of an equilibrium, although equilibrium is established more quickly
