chemistry retrieval ht 1

What is meant by the rate of a reaction?

How quickly a reaction takes place

How can you measure the volume of gas produced in a reaction?

Using a gas syringe or measuring cylinder.

What is an equation for calculating rate of reaction?

Quantity of reactant used divided by time taken

OR

quantity of product formed divided by time taken

What is the name for the theory that explains why reactions happen?

Collision theory

What must particles do for them to react with each other?

They must collide with sufficient energy.

What leads to a higher rate of reaction?"

More frequent successful collisions

What is the name given to the smallest amount of energy needed for a reaction to happen?"

The activation energy

What are the five factors that can change the rate of a reaction?

Temperature, surface area, pressure, concentration, and catalysts

What happens to the rate of any reaction if you increase any of the 5 factors?

The rate increases

How do you increase the surface area of a solid?

Break it up into smaller pieces

How does increasing temperature change the movement of particles?"

Makes them move faster

How does increasing concentration change the particles

Increases the number of particles in a given volume

How does increasing the pressure change the particles?

Makes them closer together

How do catalyst affect the rate of reaction

They lower the activation energy

What is a reversible reaction?

A reaction that can go forwards and backwards

What is the symbol for a reversible reaction?

If a reversible reaction is exothermic in one direction, what is it in the opposite direction?

Endothermic

What can be said about the the amount of energy taken in and given out in a reversible reaction?

The amount of energy taken in in one direction is equal to the amount of energy given out in the opposite direction

What is dynamic equilibrium?

When the forward and reverse reactions happen at the exact same rate in a closed system, so the concentrations of reactants and products remain constant.

What does Le Chatelier's Principle state?

If a factor changing the conditions of a system at equilibrium is altered, the position of equilibrium shifts to counteract that change.

When a reaction is at equilibrium how are the rates of forwards and backward reaction related?

They stay the same

How are the amount of products and reactants changing at equilibrium

They are not changing

What is meant by a ‘closed system’?

A reaction where no chemical leaks out