To find how concentration affects the rate of reaction

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Arran Patel 11k

GCSE Practical Chemistry Coursework

Rate Of Reaction

Aim: To find how concentration affects the rate of reaction

Background Information:

A chemical reaction is caused when particles collide with one another with enough sufficient energy. All substances are made up of particles. The more collisions there are between the particles, the faster the rate of the reaction. Collisions occur when different particles have enough energy to collide into one another, however this can be speeded up with the aid of a catalyst.

There are four common factors that can affect the rate of a reaction.

The Temperature

For every 10°C rise in temperature (0°C = 273K) there is a doubling of kinetic energy that the particles contain. This therefore increases the reaction rate as the particles are moving around and colliding more. The collisions become bigger, faster and more frequent, and so the reaction rate increases.

The Concentration

By increasing the number of particles present, you are increasing the chance of a collision, as there are more particles to collide with. Therefore increasing the chances of a faster reaction time.

The Surface area

If the reactants have a big surface area then they react quicker as more of them are exposed. The greater the surface area; the faster the rate of reaction.

The presence of a Catalyst (which we will not be investigating)

A catalyst is a substance, which speeds up a chemical reaction, however, at the end of a reaction, the catalyst remains chemically unchanged. Before reactants can turn into products, energy is required for them to start a reaction. Sometimes particles with low energy can collide but not react. A catalyst makes it easier for particles to react by altering the path of the reaction and giving the particles sufficient energy.

Thiosulphate: when this reacts with and acid it forms a precipitate. Which is a cloudy white colour. To test the strength of the precipitate we take a black cross and place it under a beaker with the reaction taking place, once the cross cannot be scene, we can say that this is the time it takes for the reaction to take place or the rate of reaction.

Equation:

Na2S2O3 + 2HCL + S + 2NaCl + SO2 + H2O

Sodium Thiosulphate + Hydrochloric Acid + Sodium Chloride + Sodium oxide + Water

Chemicle1: Sodium Thiosulphate

Chemical 2: Water (H20)

Catalyst: Dilute Hydrochloric Acid (DHA)

The collision theory:

"The more collisions between particles in a given time, the faster the reaction"

The collision theory is determined by how often and how hard the particles collide with each other. Particles have to collide in order to react with one another, but have to collide with enough force to break the bonds, so a reaction can occur.

However

Activation Energy:

A reaction is caused when particles collide with each other. For a collision to be successful the particles must have enough energy activation.

In order to react, particles need a certain amount of energy, called the activation energy. The more particles that posses this, the more that will react. A catalyst lowers the activation energy. The collision theory is determined by how often and how hard the particles collide with each other. Particles have to collide in order to react with one another, but have to collide with enough force to break the bonds, so a reaction can occur.
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Safety Points:

Wear goggles in case any of the substances used go into your eyes.

Wear a lab-coat; this not only will protect your cloths but your skin to.

Keep all long hair tied back

Do not taste or smell any of the substances, they maybe poisonous, or harmful in some way.

Fair Test Points:

Make sure concentrations used are exact otherwise the results obtained maybe invalid or wrong

Do each investigation more then once to make sure the results obtained are valid.

Make sure when watching the X on ...

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