Rates Of Reaction Essay Research Paper Rates

Rates Of Reaction Essay, Research Paper

Rates of Reaction

BACKGROUND INFORMATION

What affects the rate of reaction. 1) The surface area of the magnesium. 2)

The temperature of the reaction. 3) Concentration of the hydrochloric acid. 4)

Presence of a catalyst.

In the experiment we use hydrochloric acid which reacts with the magnesium to

form magnesium chloride. The hydrogen ions give hydrochloric acid its acidic

properties, so that all solutions of hydrogen chloride and water have a sour

taste; corrode active metals, forming metal chlorides and hydrogen; turn litmus

red; neutralise alkalis; and react with salts of weak acids, forming chlorides

and the weak acids.

Magnesium, symbol Mg, silvery white metallic element that is relatively

unreactive. In group 2 (or IIa) of the periodic table, magnesium is one of the

alkaline earth metals. The atomic number of magnesium is 12.

Magnesium(s) + Hydrochloric acid(aq) = Magnesium Chloride(aq) + Hydrogen(g)

Mg + 2HCl= MgCl2

+ H2

In the reaction when the magnesium hits the acid when dropped in, it fisses and

then disappears giving of hydrogen as it fisses and it leaves behind a solution

of hydrogen chloride.

The activation energy of a particle is increased with heat. The particles

which have to have the activation energy are those particles which are moving,

in the case of magnesium and hydrochloric acid, it is the hydrochloric acid

particles which have to have the activation energy because they are the ones

that are moving and bombarding the magnesium particles to produce magnesium

chloride.

The rate at which all reactions happen are different. An example of a fast

reaction is an explosion, and an example of a slow reaction is rusting. In any

reaction, reactants chemical reactions. products.

We can measure reactions in two ways:

1) Continuous:- Start the experiment and watch it happen; you can use a

computer .logging. system to monitor it. I.e. Watching a colour fade or

increase.

2) Discontinuous:- Do the experiments and take readings/ samples from the

experiment at different times, then analyse the readings/samples to see how many

reactants and products are used up/ produced.

Reaction rate = amount of reactant used up

time taken

If the amount used up is the same each time then the only thing that changes is

the time taken.

so, reaction rate . 1

time taken.

rate = K

time taken.

Where K is the constant for the reaction.

For particles to react:-

a) They have to collide with each other. b) They need a certain amount of

energy to break down the bonds of the particles and form new ones. This energy

is called the .Activation Energy. or Ea.

When we increase the temperature we give the particles more energy which:

1) Makes them move faster which In turn makes them collide with each other more

often.

2) Increases the average amount of energy particles have so more particles have

the .activation energy.

Both of these changes make the rate of reaction go up so we see a decrease in

the amount of time taken for the reaction and an increase in time taken.

= 1

Time taken reflects the rate of reaction.

Because temperature has an effect on both the speeds at which the particles

react and the activation energy they have a greater effect on the rate of

reaction than other changes.

A change in concentration is a change in the number of particles in a given

volume.

If we increase the volume:-a) The particles are more crowded so they collide

more often.

b) Although the average amount of energy possessed by a particle does not

change, there are more particles with each amount of energy;- more particles

with the activation energy.

a) is a major effect which effects the rate, but b) is a minor effect which

effects the rate very slightly.

In this experiment we are not concerned with whether the reaction is

exothermic or endothermic because we are concerned with the activation energy

needed to start and continue the reaction.

PREDICTIONS

I predict that as we increase the temperature the rate of reaction will

increase.

If we increase the temperature by 100C the rate of reaction will double.

I predict that if we increase the concentration of the acid the reaction rate

will increase.

If the concentration of the acid doubles, the rate of the reaction will also

double.

LINKING PREDICTION TO THEORY

Reaction Rate and Temperature.

The collision theory describes how the rate of reaction increases as the

temperature increases. This theory states that as the temperature rises, more

energy is given to the particles so their speed increases, this increases the

number of collisions per unit of time. This increase in collisions increases

Внимание, отключите Adblock

Вы посетили наш сайт со включенным блокировщиком рекламы!
Ссылка для скачивания станет доступной сразу после отключения Adblock!

Скачать