Chemical Reactions and Equilibrium Flashcards
What is a chemical reaction?
A process in which as least one new substance is produced as a result of chemical change.
Occurs when new bonds form or old bonds break. Foundation of all life processes.
What are reactants and products.
Reactants - starting substances.
Products - end substance.
Number of atoms in each element is same before and after reaction
What are the 5 major chemical reactions types?
combination, decomposition, displacement, exchange and combustion reactions
What is the Law of Conversion Matter?
Matter cannot be created or destroyed during a chemical reaction
What is activation energy?
Initial energy investment needed to start a reaction.
Reactants must absorb enough energy for their chemical bonds to become unstable and form new combinations
As new bonds form, energy is released into surroundings
What is a combustion reaction?
Most common type of reaction - between substance and oxygen, creates heat and light
Oxygen tends to take away electrons
Hydrogen tends to give electrons
What is a redox reaction?
Oxidation-reduction
A chemical reaction in which there is a transfer of electrons from one reactant to another. One undergoes oxidation, another undergoes reduction
What is the oxidation number?
Represents the change that an atom has when electrons in each bond it is participating in are assigned to the more electronegative of the two
What are the oxidation number rules?
- Oxidation number of an element is zero
- ON of monatomic ion is equal to charge of ion
- ON of groups IA is 1+ and IAA is 2+
- ON of hydrogen is 1+ in most hydrogen containing compounds
- ON of oxygen is 2- in most oxygen containing compounds
- In binary molecular compounds, the more electronegative element is assigned a negative ON equal to its charge
- For a compound, the sum of the individual ON is equal to zero. For polyatomic ion, sum is equal to charge on ion
What are the electron transfers of the following terms:
Oxidation
Reduction
Oxidising agent
Reducing agent
Oxidation: loss of electrons
Reduction: gain of electrons
Oxidising agent (substance reduced): electrons gained
Reducing agent (substance oxidised): electrons lost
OIL RIG
Oxidation is loss (of electrons)
Reduction is gain (of electrons )
What is an oxidising agent?
The reactant that causes oxidation of another by accepting electrons from it
What is a reducing agent?
The reactant in redox reaction that causes reduction of another by providing electrons for other to accept
What is collision theory?
- Reactant molecules must collide with each other
- Colliding reactants must possess certain minimum amount of energy
- Colliding reactant must be oriented in a specific way for reaction to occur
What is an exothermic chemical reaction?
Releases energy as the reaction occurs
What is an endothermic chemical reaction
Requires input of energy as reaction occurs
What is chemical equilibrium?
Rate of forward reaction is equal to the rate of reverse reaction.
Both processes occurring simultaneously, even though there is no observable change
What is equilibrium constant?
Concentration of reactants and products at equilibrium
What is equilibrium position?
Relative amounts of reactants and products present in a system at equilibrium.
What is Le Chateliers principle?
If a stress (change in conditions) is applied to a system in equilibrium, the system will readjust (change the equilibrium position) in the direction that best reduces the stress imposed on the system
What does is mean if the equilibrium shifts to the right or the left?
Right = more products have been produced
Left = more reactants form
Concentration change on reactions
- More particles of matter present, greater chance they will collide
- concentration increases when more are added to a space or pressure on space increases
Temperature change on reactions
As the temperature rises, particles more more rapidly, more forcefully particles collide/greater chance of collision
What are catalysts?
Chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur
Helps to orient colliding particles, interacting at precise spots to make reaction happen
Catalyst itself is unchanged at end of reaction
