Investigating Factors That Affect The Rate Of Reaction Between Marble Chips And Hydrochloric Acid.

Authors Avatar

Chemistry Coursework:

Investigating Factors That Affect The Rate Of Reaction Between Marble Chips And Hydrochloric Acid.

Skill Area P

Planning and Investigational Procedures.

To investigate how concentration affects the rate of reaction we will be reacting calcium carbonate and hydrochloric acid. To make this a fair test we will have to keep all variables the same. The products of the reaction between calcium carbonate and hydrochloric acid are calcium chloride and carbon dioxide. To measure the rate of reaction we will be measuring the volume of carbon dioxide produced. The size of the marble chips available will be small, medium and large. Activation energy should not be changed in this experiment though as the same amount 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.

 Calcium carbonate will react with hydrochloric acid, because it is higher in the reactivity series than hydrogen. When the two chemicals react a displacement reaction will take place and the calcium carbonate will displace the hydrogen in the hydrochloric acid forming calcium chloride, water and carbon dioxide gas.

The equation for this reaction is:

CaCO3(s)        +        2HCl(aq)         =      CaCl2 (aq)        +    H2O (l)   + CO2 (g)

(Calcium        +       (Hydrochloric   = (Calcium Chloride)+  (Water)   + (Carbon

Carbonate)

Variables:

The variables that may have an affect on this experiment are:

  • Size of calcium carbonate chips-

The size will determine the rate of the reaction, if the chips are small like powder, then they would have a larger surface area, therefore the rate would speed up because the bonds would be easier to break up because more of the acid particles will have more access to more of the powder which would make it faster. If the chips were bigger, they would have a smaller surface area overall, this means that the acid will have less area to act on to dissolve.

  • Concentration of the hydrochloric acid-

If the acid is diluted with water it would make it weaker and also slower to react with the chips of calcium carbonate and because there are less particles of the reactant between the water molecules, which would have enabled it to make more collisions and therefore react quicker. Whereas if the solution has a stronger concentration with less water or none at all it would react at a faster rate, this is because there will be more of the particles reacting and colliding at a more faster rate than a solution with a weaker concentration and larger surface area.

  • The temperature of the acid-

The reaction gets its energy from the heat and temperature it is working at. The heat gives the reaction energy; as this energy is given, the particles begin to collide, and as the temperature increases, as does the amount of energy there is to collide with each of the different substances of particles which will collide the fastest. If the temperature is low, there would be less energy given to the particles for more collisions per second and the reaction would either not begin or begin very slowly.

  • Surface area of the conical flask-

If the flask has got a small base, the acid and the marble chips will be more compressed together, meaning that the acid is closer to the chips surrounding it thus covering a larger surface area of particles. With the chips closer together it means that the collisions will occur more often because the particles will not loose their energy travelling to another particle otherwise the collisions will be less.

  • Amount of chips-

If the amount of chips is more than the amount of acid it means that the chips will have less particles of acid between their particles, therefore making an unequal amount of each product, which will slow down the

  • Amount of hydrochloric acid-

If there is more of the acid compared to the chips (similar reaction rate. If there were less chips compared to the acid the reaction will be faster because more of the acid will be present for each separate chip and more of the surface area will be covered which means more of the acid will be acting upon it.

For the explanation above: more of the acid will be there to react with the chips therefore it will be faster. If there were less of the acid than the chips, little acid will be there to react with the chips therefore it will be slower because less percentage of the acid is there to cover less surface area of the calcium carbonate.

  • Surface Area-

If the calcium carbonate had a bigger surface area each time the experiment was done, then the acid particles will have a bigger area to collide with, so more collisions will occur every second and the more collisions per second than the more successful collisions per second.

  • Catalysts-

By weakening bonds this increases the rate of reaction by lowering activation energy a catalyst will not be used in this reaction, however.

All of these factors will change the rate of reaction because of the Collision Theory. This is a theory that is used to predict the rate of a reaction. The Collision Theory is based on the idea that for a chemical reaction to take place, it is necessary for the reacting particles to collide with each other with enough energy to break or form new bonds between the other particles, which is called a successful collision. If when they collide and they do not have enough energy to break or form new bonds then they will simple bounce of each other, causing an unsuccessful collision.

Plan – Apparatus:

  • Boiling tube
  • Measuring cylinders (100ml, 50ml, 25ml and 10ml)
  • Calcium carbonate chips (3.24g, 3.  g, 3.  g, 3.  g,     g)
  • Hydrochloric acid (50cm³, 40cm³, 30cm³, 20cm³, 10cm³, 0cm³)
  • Water (50cm³, 40cm³, 30cm³, 20cm³, 10cm³, 0cm³)
  • Stopwatch
  • Gas syringe
  • 100cm³ Conical flask
  • Bung on the top of the boiling tube with a delivery tube connected to the gas syringe.
  • Stand
  • And a clamp to hold on to the syringe.

Diagram:

Step by step plan:

When doing my experiments I will use the same procedure throughout. Once I have set up the apparatus I will measure out 50cm³ of acid in a 100ml measuring tube. Once the acid has been poured onto the marble chips my colleague will be ready with the stopwatch to start the time, and I will push the bung onto the 100cm³ conical flask. This must all be done in a very short space of time.

Join now!

From there, we recorded the volume of gas every twenty seconds because this was a suitable time interval for finding a measurable change to take place. The time we will be measuring for this experiment is two hundred and forty seconds because this gave us enough data for us to draw an accurate graph and we would not have to wait too long to complete one experiment. This also gave us time to repeat the experiment two times so we would have more accurate averages. We will be measuring the cylinder to the nearest cm³ because this is how often ...

This is a preview of the whole essay