Topic 6 – The Rate and Extent of Chemical Change

How is rate of reaction calculated?

Rate of reaction= amount of reactant used or product formed / time

Rate of reaction(mol) = moles of reacting to used a product formed/ time

What are the various units for the rate of reaction?

Generally mass/time volume/time moles/ time

Name three common ways of measuring rate of reaction

Loss in mass of reactants

Volume of gas produced

Time for a solution to become opaque

Described measuring the rate by monitoring mass loss

Place the reaction flask on a balance

In these reactions are gas is given off to record the decrease in mass in time intervals and plot a graph of mass versus time

Describe measuring the rate by monitoring the volume of gas

Connect to gasoline to a reaction flask and measure the volume of a gas formed in intervals plot a graph of volume versus time

Describe me measuring the rate by monitoring the disappearance of a cross

Take a piece of paper mark across on it put the reaction floss on this cross mix the reagent and measure how long it takes for a cloudy mixture to concealer across

How to find a rate of reaction at the same time from a graph of amount of reactant time

Pick up point corresponding to the time T and find the tangent to the car at this point

The tangent is the gradient of the graph and it tells you how faster reaction proceed at a point the steeper the tangent line. The faster the rate gradient of tangent can be expressed in changing. Why values of changing X values

State five factors affecting the rate of a chemical reaction

Concentration of reactants

Pressure of gas

Surface area

Temperature

Catalysts

What is the collision theory?

Chemical reactions can a occur only when reacting particles collide with each other with sufficient energy more than or equal to the activation energy

Describing and explained the effect of increasing temperature on the rate of reaction

Temperature increases = foster reaction

As temperature increases kinetic energy of the particle increases so they move faster and collide more frequently however they're not directly proportional to each other

Describing and explain the effective increasing concentration on the rate of reaction

Concentration increases = foster reaction

More reactants equals more frequent collisions

Describing and explain the effect of increasing pressure of a gas on the rate of reaction

Increasing the pressure of reacting gases is the same as in increasing concentration. It increases the number of gas molecules in the same volume and increases the frequency of collisions and therefore increases the rate of reaction.

Volume and pressure inversely proportional to each other

Describing and explain the effect of increasing surface area

If solid reactants are in smaller pieces, they have greater surface area

Increasing the surface area of solid reactants increases the frequency of collisions and so increases the rate of reaction

What is a catalyst and how does it work? How does it affect the reaction profile?

A catalyst changes the rate of reaction but is not used up

It increases rate of reaction by providing a different pathway for the reaction that has a low activation energy

The reaction profile for a catalysed reaction will have a lower maximum of the curve or lower activation energy

What is an enzyme?

A biological catalyst

What is the reversible reaction?

When the product of a reaction can react backwards to produce the original reactants

When is dynamic equilibrium reached?

In a close system when the Ford and reverse reactions are occur at the same rate and the concentrations of reactants and products remain constant

Describe le Château's principal

If a system is that equilibrium and a change is made to one of the conditions then the system responds to counteract changing restore equilibrium

Describe the effective changing the concentration of reactant and product on the position of equilibrium

If the concentration of one of the reactants or products has changed, the system is no longer equilibrium and the concentration of all the substances will change into equilibrium has reached again

If the concentration of a reactant is increased more products will be formed until the equilibrium is reached again

If the concentration of a product is decreased, more reacts will react into the equilibrium is reached again

Describe the effect of changing temperature on the position of the equilibrium

If the temperature of a system of equilibrium is increased:

The relative amount of product that equilibrium increases for an endothermic reaction

The relative amount of product are equilibrium decreases for an exothermic reaction

Describe the effect of changing pressure on the position of the equilibrium

This only applies to the equilibrium that involves gases

An increase in pressure causes the equilibrium position to shift towards the side with the smaller number of molecules as shown by the similar equation for that reaction

A decrease in pressure causes the equilibrium position to shift towards this side with a large larger number of molecules are shown by the same book equation for that reaction

Pressure has no effect on the reaction to where the numbers of gas molecules that equal on both sides of the equation

Describe the effect of a catalyst on the position of equilibrium

No effect, but it just speeds up both forward and backward reactions equally to achieve equilibrium faster