I have to investigate the factors that affect a chemical reaction:
Calcium Carbonate + Hydrochloric Acid
Calcium Chloride + Carbon Dioxide
The easiest way to determine a change in the reaction is how much carbon dioxide is given off during the reaction.
The variables that affect this reaction are:
稢oncentration of Hydrochloric Acid
With the help of 'Chemistry in Context' by G. Hill and J. Holman I already
know the following information.
During a chemical reaction the reactants are converted to products. The reaction rate tells us how fast the reaction is taking place by indicating how much of a reactant is consumed or how much of a product forms in a given time. For example:
Reaction rate= change in amount (or concentration) of a substance
This reaction rate can be seen as the rate of change of amount or concentration of a certain reactant or product. Normally reaction rates are expressed in moles of dm- s- or in mole s- as this is convenient. However, it is more convenient to use minutes as the unit of time as it is easier to work out.
Biological reactions rely on the presence of catalysts. One or more catalysts control almost every chemical reaction in your body. Catalysts are involved in simple reactions like the hydrolysis of starch to sugars. They are also involved in highly complex reactions like the replication of DNA, which forms the genes in the nuclei of cells. These are called enzymes.
Temperature affects chemical reactions also, because as the temperature rises the average speed of reacting particles increases. There will be more collisions per second if the temperature is high, resulting in an increase in the rate of reaction. This Collision Theory links to the Kinetic Theory, which can be explained as follows:
In solids, the particles are relatively close together. They have smaller amounts of energy than that of liquids and gaseous states at higher temperatures. Therefore, solid particles cannot overcome the strong forces of attraction that holds them together. Solids can only vibrate in their fixed positions.
The particles are slightly further apart in liquids than they are in solids and they also have more energy, so they are able to overcome the forces between each other to some extent. They can move freely around each other whilst staying near too.
The particles are spread out in gases, much more than liquids and also have a lot more energy. Gas particles nearly have enough particles to overcome all forces of attraction completely. They move very fast in all directions. Also an increase in the average Kinetic Energy of particles can be caused by an increase in temperature
Temperature is the variable I will be using, as it is the simplest to do. The Surface Area would be far too hard to find. I am not using any Catalyst. Changing the Concentration of the Hydrochloric Acid would be too hard and would take too much to measure out.
I have to make my experiment Safe. To do this I will wear goggles to protect my eyes from the Hydrochloric Acid, as this is a dangerous chemical substance. I will tie my hair back, make sure my tie is tucked in and put my bag and coat well away under the desks, along with the stools.
I have to make sure I perform a Fair Test. This means I have to be very accurate in everything I do. If the test is inaccurate it means that it is unfair. To make sure it is a fair test I will use the same amount of hydrochloric acid each time (50ml) and the same amount of marble chip (2g). The water in the measuring cylinder will always be the same too. I shall perform the experiment for ten minutes and take a reading every minute for accuracy. I will also repeat the experiment twice over.
The Apparatus I shall be using are:
Conical FlaskGas SyringeThermometer
Water BathBossDelivery Tube
Fibre BoardBeakerElectronic Scales