To Investigate the Rate of Reaction Between Calcium Carbonate and Hydrochloric Acid

Aim: To investigate the rate of reaction between Calcium Carbonate and Hydrochloric Acid.

Just from looking at the aim of the investigation I already know that a salt would be formed because a carbonate with an acid forms a salt. In this investigation the substance that is formed is Calcium Chloride, Water and Carbon Dioxide. The symbol equation for this is:

CaCo3  Ca2+ + Co32-

Hcl  H+ + Cl-

Add these all together to get

CaCO3(s) + 2H+(aq) --> Ca++(aq) + H2O + CO2(g)

The rate of reaction is just the speed at which the substances on the left side of equation turn into the substances on the right side. The way we measured the rate of reaction today was measuring the how quickly carbon dioxide gas was produced in each experiment.

A reaction occurs when particles collide. This process is based on random particle movement. So therefore, the more particles you have in a space, the more likely they going to collide. Therefore making the reaction accelerate. This theory can be proved if you compare the rate of reaction with marble in hydrochloric acid. 'If the acid is of a higher concentration, the reaction will be quicker.' Also if the particles have more energy, they will be traveling faster, making them collide more frequently.

In this investigation the factors that can change the rate of reaction are:

1. Temperature; when the temperature increases the particles moves faster, causing more collision in a certain time. Therefore the quicker the reaction. Another reason why the rate increases is that some colliding particles just 'bounce' off each other; they cannot 'bang' hard enough to create a reaction due to there being not enough energy. Basically the higher the temperature roughly doubles the rate of many reactions.

2. Surface Area; the smaller the pieces the larger the surface area becomes. We find that the small pieces of solid, especially powder react faster then large pieces. It is like frying two pans one with chips and the other with a potato. The surface area is measured of how much area is exposed. They both have the same mass however the chips have a larger surface area.

Reducing the size of particles increases the rate of a reaction because it increases the surface area available for collisions to take place. This increases the number of collisions. It has no effect on the energy of the particles.

3. Concentration; the higher the concentration the faster the reaction because there would be more Hcl to 'bump' into CaCo3. To make this a far test there must be the same volume in each beaker. The more hydrogen makes it more acidic. Hcl is a gas that has to be mixed with water into a concentration.

4. The last factor is the Catalyst that is a substance that speeds up a chemical reaction. At the end of the reaction the catalyst is chemically uncharged. The energy needed to start a reaction is called activation energy. A catalyst leaver the activation energy. It makes it easier for particles to react.

The factor that I will investigate is concentration. To make the evidence reliable and precise I will keep the amount of volume the same that will be 2ml. I will also keep the weight of the CaCo3 chip the same.

Hypothesis: The more concentrated the substance, the greater chance of the Hydrochloric Acid there is to collide with the Marble chip giving a more produced; carbon dioxide.

The concentration of a solution is how strong the solution is. For example, in this case the reaction between marble chips (calcium carbonate) and hydrochloric acid: calcium carbonate + hydrochloric acid --> calcium chloride + water + carbon dioxide

Then a stronger acid contains more H+ ions and less water particles than a weaker acid. Increasing the concentration of a solution leads to more collisions (greater frequency of collisions) so the rate of the reaction goes up. In a less concentrated acid, the number of collisions is low, so the rate of the reaction is slower. (The water particles aren't With a more concentrated acid, the number of acid particles is greater, so the number of collisions is greater and the rate of the reaction is higher (faster): Changing the concentration of the acid does not change how quickly the particles are moving (i.e. it doesn't increase the amount of energy they have).

Method:

First of all I will set up my equipment.

*I will get a conical glass that will have a bung placed on top because this will stop anything from entering and leaving that may affect the investigation. A tube will then go from the bung to the bee hive shelf; this will be under the water. On top of this will be a measuring tube that will be full of water because when the gas bubbles come up the water will decrease, giving me the amount of gas given off.

*Then weight 2.0g of medium sized marble chip and 25 ml of substance.

*Prepare to start stopwatch put marble chips in with acid & put bung on conical flask whilst starting stopwatch every minute until 8 minutes starting from 0s take a measurement of how much air there is in measuring cylinder (cm3) When finished this with the first concentration of acid clean out the conical flask and refill the measuring cylinder & repeat experiment.

During this investigation I will wear goggles due to health and safety rules. I will also record my results into a table when doing the experiment. With the results I will record them into a scatter graph therefore I can compare the results. I will then section the graphs into 4, every 2 minutes so I can compare what is happening in each section and why. Therefore I can understand what is happening with the reaction.

Preliminary Test:

Before I do this experiment I will do a preliminary test because it will help me understand what is happening, see if it is a fair test and if it is suitable for the investigation. In addition help me decide whether to use a one molar or two molar solutions.

Hypothesis: The two molar will give off double the amount