Chemistry Unit 1:

Collision Theory

For particles to react, they must collide with sufficient energy and the correct orientation.

Activation Energy

The minimum amount of energy required for a reaction to occur.

Exothermic Reactions

Reactions that release energy into the surroundings, increasing temperature.

Endothermic Reactions

Reactions that absorb energy from the surroundings, decreasing temperature.

Mole

A unit for measuring the amount of a substance, defined as 6.02 × 10^23 representative particles.

Avogadro’s Number

The number of particles in a mole, approximately 6.02 × 10^23.

Polyatomic Ions

Groups of atoms bonded together with an overall charge that move as a single unit.

Le Chatelier’s Principle

When a change is made to an equilibrium, the equilibrium shifts to counteract the change.

Catalyst

A substance that speeds up a reaction without being consumed by lowering the activation energy.

Maxwell-Boltzmann diagram

A diagram that shows the distribution of energy among particles in a system.

Surface Area

The extent of a solid's outer area, which can be increased to allow more frequent collisions, speeding up the reaction.

Chemical Equilibrium

A state in a reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction.

Concentration

The amount of substance per unit volume, typically measured in moles per cubic decimeter (mol/dm³).

Bond Energies

The amount of energy required to break a bond between atoms.

Enthalpy Change

The total energy in a chemical reaction, represented by the difference between energy absorbed and released.

Pressure (in reactions)

An increase in pressure shifts equilibrium to the side with fewer moles of gas to decrease pressure.

Temperature (in reactions)

Increasing temperature shifts equilibrium toward the endothermic direction, while decreasing shifts toward the exothermic direction.