The Effect of Concentration on the Rate of Reaction between Hydrochloric Acid and Calcium Carbonate (marble) Chips.

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CONTENTS PAGE

PLANNING        

Introduction        

Background Knowledge        

The collision theory        

Diagrams to show the particles reacting in a high concentration level and a low concentration level of hydrochloric acid        

Prediction        

The Experiment        

The outline of the plan        

Measurments        

Fair Test        

Apparatus        

Diagram to show the setup of appartus        

Safety        

Method        

OBTAINING EVIDENCE        

Introduction        

Results Table        

Tables to show the results obtained from the effects of different concentrations on marble chips on the varied rates of reaction.        

Table of results to show the set of averages processed from each experiments concentration results.        

Graph – Showing the rate of reaction from differnet concentrations        

ANALYSING AND CONSIDERING EVIDENCE        


The Effect of Concentration on the Rate of Reaction between Hydrochloric Acid and Calcium Carbonate (marble) Chips

Planning

Introduction

This investigation is to obtain a set of reliable results and a strong conclusion, of the effects from different hydrochloric acid concentrations, reacting on small calcium carbonate chips; measuring the rate of reaction of which carbon dioxide is produced as a product. My primary aim is to find the change in reaction rate when the concentration is increased. Below is a balanced word and symbol equation of this reaction and its products, between hydrochloric acid and calcium carbonate:

CaCo3 (s) + 2HCL (aq) → CaCL 2 (aq) + H2O (l) + CO2 (g)

Hydrochloric acid + Calcuim Carbonate  Calcuim Chloride + Water + Carbon Dioxide

There are many factors which can influence the rates of a chemical reaction: temperature, surface area, use of a suitable catalyst and concentration. The rate of a chemical reaction can be followed by measuring the rate of which the products are formed on the rate at which the reactants are used up, and in this case by recording time in seconds. Chemical reactions can also occur at diffenet speeds depending on their factors and their enviroment.

In this reaction the factor that will be investigated is the different concentrations of hydrochloric acid on small marble chips, and how fast its rate of reaction is in producing a certain amount of carbon dioxide.  From research gathered and previosuly conducted experiments, it has been established that the higher the amount of concentration there is in  each solution the faster the rate of production. I have decided there will be five concentrations tested, 100ml3, 75ml3, 50ml3 25ml3 and 0ml3; each test will be repeated twice to create an average for each experiment, to guarnatee all the results are correct and are similar to one another to prevent anomalies.

Background Knowledge

The collision theory

The reason for a higher amount of concentration to produce a faster rate of reaction is caused because of the ‘collision theory’. The collision theory suggests particles need to collide with enough energy to react sufficiently, and the higher level of a particular factor (for example: concentration) the higher the rate of reaction there will be. If the particles are given enough energy, they will collide with other particles and break their bonds, causing a reaction to occur. From the kinetic theory of gases in a reaction between two gases A&B, a molecule of ‘A’ must collide with ‘B’ for the reaction to proceed but in a concentrated solution there will be a higher percent of reactants which will have no more energy. Not all collisions cause a reaction, only the ones which reach the activation energy of the reaction. This is what produces the products of the reaction; as the reactants are spilt up other substances will displace on another depending on their position in the reactivity series, an example in this investigation would be:

Calcium Carbonate + Hydrochloric Acid  

Here are the reasons why for each factor/ variable a reaction occurs and what effects they would have on this experiment:

  • Temperature- The higher the temperature the more energy each particle will have which means it will vibrate more, causing the amount of collisions to increase. If the particles collide more, the rate of reaction is increased.
  • Concentration of Acid- The higher the concentration of acid, the more particles there are to react with. If for example the concentration of Hydrochloric acid is doubled then there are more Hydrochloric particles present and so there will be more chance of the particles colliding.
  • Surface area- if one of the reactants is a solid then it can be broken down into smaller pieces or into a powder. This gives the reactant a larger surface area, meaning there is a larger surface to work on and so there is more chance of particles colliding.
  • Activation Energy Needed- Reactions only happen if the particles collide with enough energy. At a higher temperature there will be more particles colliding with enough energy to make the reaction happen this amount varies from different elements and type of reaction.  This initial energy should not be changed in this experiment though, as the same amount of energy will be required to break the bonds. This is because each particle has the same amount of energy, the only reason the reaction is faster is because there are more particles. This means activation energy will not have an effect on this experiment.
  • Catalyst- A catalyst will lower the activation energy and makes more successful collisions, by weakening the bonds and increasing the rate of reaction. When the activation rate is lower not much energy is needed to make the reaction successful. However it will not be needed in this investigation.
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From these theories we can identify what would make the fastest rate of reaction, which would be the concentration of acid and largest surface area which would be the smaller marble chips. Therefore from this I gave decided that I will use the effects of concentration on the smaller marble chips, because both have higher rates of reaction that any other variables.

Below shows what happens during the collision theory with the effects of concentration, the diagrams shows the more particels there are in a higher level of acidic concentration, the more reactions will take place and faster ...

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This is a good experiment write up which is let down by the lack of a meaningful analysis and considering evidence section. For an introduction and scientific information on the collision theory it is excellent. But overall 3 stars.