Investigating the reaction between Marble Chips and Hydrochloric Acid.

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Investigating the Reaction between Marble Chips and Hydrochloric Acid

Background Information

The reaction rate tells us how fast or slow a chemical reaction is and there are four factors that can affect this greatly, they are:

Concentration: An increase in concentration means there are more particles. More particles means there will be more collisions. This should increase the reaction rate.

Surface Area: When one of the reactants is solid, the reaction can only take place at the surface of the solid. Breaking the solid into smaller pieces will increase the surface area exposed to the other reactant. This should increase the reaction rate.

Temperature: Since temperature is a measure of the motion of particles, increasing the temperature will cause the particles to move faster. When particles move faster, more collisions occur and the collisions are more violent. This should increase the reaction rate

Catalysts: Catalysts are substances that change the rate of a chemical reaction without being changed in the reaction. Catalysts are most often used to speed up a chemical reaction. They do so by changing the steps needed between reactants and the formation of the products. If the number of steps can be reduced, the reaction rate should increase. The Reaction Rate is often called the "Collision Theory", which describes the way temperature, concentration and surface area of the solid reactant affects the rate of reaction, by affecting collisions from particles.

Particles react when they collide with sufficient energy. At a higher temperature collisions are more frequent and they also have more energy, both because particles are moving faster. At a higher concentration collisions are again more frequent, as there are more reactant particles in the liquid. Increase surface are of the solid again increases the frequency of collision between reacting particles, as the liquid reactant has greater contact with the solid one. Adding a catalyst can also increase the rate of reaction, but there is not one used in this experiment.

Light intensity: Light intensity can have a very small affect on a reaction.

Aim

My aim is to investigate the affect on the volume of carbon dioxide gas produced inside a time limit if I vary the concentration (mol) of Hydrochloric Acid when it is reacted with Marble Chips. To make this a fair test I shall keep every variable the same except the one I am investigating (Concentration).

For this investigation I shall be investigating the reaction between calcium carbonate and hydrochloric acid. The products of the reaction between calcium carbonate and hydrochloric acid are calcium chloride and carbon dioxide. Below are word and symbol equations for the experiment:

Calcium Carbonate + Hydrochloric Acid Carbon Dioxide + Water + Calcium Chloride

CaCO3 + 2HCl CaCl2 + H2O + CO2

Prediction

I predict that as the concentration of the hydrochloric acid decreases, so does the value recorded of the volume of carbon dioxide gas collected, at each time station (the time stations are at 30 second intervals at: 0 seconds, 30 seconds, 60 seconds, 120 seconds and 150 seconds).
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I predict that in the later stages of the timed reaction, the rate will slow down. I was able to make these predictions due to my background knowledge on how the variable of concentration of an acid affects the rate of a reaction (the more concentrated the acid is, the quicker the reaction).

Apparatus

For the experiment, I shall need:

* A Stopwatch

* A Gas Syringe

* Hydrochloric Acid

* Marble Chips (with diameters of between 2mm and 4mm)

* A Spatula

* A Delivery Tube

* A ...

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