N-Particles and Rates

Flashcards about states of matter and rates of reaction

What factors define the three states of matter?

Arrangement, movement, and energy of the particles

What are the key components of interconversions between the three states of matter?

Names of the interconversions and how they are achieved

What occurs during the interconversions between the three states of matter?

Changes in arrangement, movement, and energy of the particles

What experiments help explain the particle nature of matter?

Diffusion of gases and dilution of colored solutions

What factors affect the rate of a reaction?

Surface area of a solid, concentration of a solution, temperature, and the use of a catalyst

What is a catalyst?

A substance that increases the rate of a reaction but is chemically unchanged at the end

How does a catalyst work?

Providing an alternative pathway with lower activation energy

What does a reaction profile diagram show?

Illustrates AH and activation energy

What are the three states of matter?

Gas, Liquid, Solid

What are the characteristics of particles in a gas?

Far apart, low densities, move rapidly and randomly.

What are the characteristics of particles in a liquid?

Close together, denser than gases, move slowly and randomly.

What are the characteristics of particles in a solid?

Close together, denser than gases, vibrate only in fixed positions.

What is diffusion?

Random movement of molecules from high to low concentration

What is absolute zero?

The theoretical temperature at which all particle motion stops (-273 °C or 0 K)

What happens to particles when heated?

Particles vibrate more quickly and energetically

What happens during melting?

The lattice structure is disrupted as particles gain enough energy to break some bonds. Temperature is constant.

What happens when a liquid is heated?

The liquid is heated, particles move more quickly, and average Ek increases.

What happens during boiling?

Additional energy breaks all remaining attractions. Temperature is constant.

What measurable quantities show rates of reaction?

Decrease in mass, gas volume changes, color changes, precipitations

What is a reaction mechanism?

The sequence of steps involving collisions between particles during a chemical reaction

What must happen for particles to react?

Particles must collide with enough energy (activation energy) to break chemical bonds.

How does concentration affect reaction rate?

High concentration leads to a large number of reactant particles per unit volume and increased collision frequency.

How does particle size affect reaction rate?

Powders have a greater surface area at which chemical reactions can occur, increasing collision frequency.

How does gas pressure affect reaction rate?

Increased pressure forces particles closer together, increasing collision frequency.

How does temperature affect reaction rate?

Increased temperature increases collision frequency and more particles have the necessary activation energy.

How does a catalyst affect reaction rate?

Increases the rate of a chemical reaction without itself being consumed, by providing an alternative path with lower activation energy.