• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

How Concentration of Acid affects rate of reaction.

Extracts from this document...

Introduction

Chemistry Coursework - How Concentration of Acid affects rate of reaction Plan I shall investigate whether the concentration of an acid affects the reaction rate between an acid and a carbonate. I shall vary the concentration of acid, but keep the other potential variables constant. These include: * Time - if an experiment has longer to take place than another, unless the reaction has finished, differing the time over which the experiment will take place will distort the results. This is because it has longer to react. So there is longer for the reactants to come into contact with each other. I shall use a stopwatch to keep the time constant between experiments. * Heat - if the heat of the solution and/or chips is different between experiments, this will affect the result. Increased heat means that molecules are moving faster. This will lead to more molecules of acid coming into contact with the carbonate in the same timeframe. Crucially, it will also mean that more molecules collide with enough force to power a reaction. Both of these reasons mean that heat should be kept constant between experiments. Ideally, the conical flask should be placed in a water bath to regulate the temperature. However, due to time constraints, this was not possible, so I could not use water baths and had to rely on a constant room temperature. * Surface area of chips - if one chip has a higher surface area but the same mass, than another, and they are both placed in an acid solution, the chip with the larger surface area will come into contact with more acid molecules, so it will react faster as there are more possible areas for the reactions to take place. ...read more.

Middle

I chose these cylinders for the concentrations because they were the lowest measuring cylinders available for the amount of gas produced (including a little room for safety)). b) Thread tube from conical flask through pneumatic trough and into measuring cylinders. 3. Place plastic tray on scales and add 2.0g of 2-4mm calcium carbonate chips onto it (it is a good idea to 'zero' the scales onto the plastic tray) 4. Measure solution into 20ml measuring cylinder. For a concentration of 0.0M, 20ml of distilled water is needed. For a concentration of 0.4M, 16ml of distilled water and 4ml of 2.0M hydrochloric acid is needed. For a concentration of 0.8M, 12ml of distilled water and 8ml of 2.0M hydrochloric acid is needed. For a solution of 1.2M, 8ml of distilled water and 12ml of 2.0M hydrochloric acid is needed. For a concentration of 1.6M, 4ml of distilled water and 16ml of 2.0M hydrochloric acid is needed. For a concentration of 2.0M, 20ml of 2.0M hydrochloric acid is needed. Pour the solution into the conical flask. 5. Drop chips into conical flask, place bung on top and start stopwatch. 6. Monitor stopwatch and when it reaches 30s, look to see how much gas was displaced from the measuring cylinder and record this. 7. Clean apparatus and repeat steps 2-7 for different concentrations of acid. Other Notes I am measuring the amount of carbon dioxide produced. This is because it is the gas formed in this reaction: calcium carbonate + hydrochloric acid � calcium chloride + water +carbon dioxide. The strength of the acid is governed by the % hydrogen ions which dissociate. ...read more.

Conclusion

This would ideally have been in my experiment, however, due to time constraints I could not include it. I think I took enough measurements to the correct degree of accuracy and over an appropriate range, because I managed to find out that concentration2 is directly proportional to the initial rate of reaction. The results I took followed the line of best fit, so that suggests that they are accurate too. The experimental uncertainties are within acceptable limits as they follow the line of best fit closely. The only result I found which was not within acceptable limits, I retook and as it was anomalous, I disregarded it when drawing an average. I would change the measuring cylinder to a burette, for increased sensitivity and accuracy. I would also prefer to use powdered calcium carbonate, as there are no problems of surface area: mass ratio because the powder will have the same surface area: mass ratio (because the powdered chips are relatively the same size). However, in order to use the powder, an automatic stirrer would be needed to stop the powder clinging together. The acid should also be changed to one that disassociates less, in case the powdered calcium carbonate reacts a lot more than the small chips of calcium carbonate. It could also be useful to test some other concentrations of acid, especially ones which are a lot stronger, to see if the conclusion is valid for these values. Higher values have another advantage because any small error in the line when it is shown with small values of concentration will not be so pronounced, it could be due to experimental error. However, when the concentration increases, any small error in the line of best fit on the graph will be more pronounced. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. Marked by a teacher

    To see how the concentration of acid, reacting with potassium carbonate, affects the rate ...

    4 star(s)

    * Ice * Stop clock * Paper and pen In some cases I will repeat the experiment if needed. I will be testing the following mixtures of hydrochloric acid and water: Vol. of 2M hydrochloric acid (cm3) Volume of distilled water (cm3)

  2. Analysing the ethanoic acid concentration in different types of vinegars.

    Maximum % error = Maximum possible error/ volume used x 100 Titration Scales: Accuracy of equipment = 0.001g, Weight measured = 10g Max possible error = 0.0015 Max % error = 0.0015/10 x 100 = 0.015 Volumetric flask: Since I used this twice for each trial I will multiply the result I obtain by two.

  1. To investigate the effect of concentration on the temperature rise, heat evolved and heat ...

    The overall results state that the heat evolved is less than the predicted heat evolved. This may be because I didn't notice the temperature reading properly, or I might have added less acid or alkali, or I might have waited too long before I took the reading or I stirred the solution less.

  2. To investigate the rate of reaction between different concentrations of hydrochloric acid with metal ...

    + 2H+(aq) � CO2 (g) + H2O (l) As the acid react with the carbonate ion (CO3), the Ca2+ and the Cl- ions are present in the start and the finish of the reaction, they are called spectator ions and since they are not involved in a chemical change, they can be excluded from the reaction.

  1. How much Iron (II) in 100 grams of Spinach Oleracea?

    The whole solid may not have dissolved fully in the acid/distilled water needed to create the correct concentration of solutions in both the Oxalic Acid (aq) and the Potassium Manganate (VII) (aq). If this had occurred the solutions produced would have been less concentrated resulting in any equations done using their concentration being inaccurate.

  2. Investigating the effects of changing the concentration of different solutions on the refractive index ...

    Analysis After collecting the refractive index of different concentration of salt solutions and sugar solutions, I have drawn out Fig.1 and Fig.2 showing how the refractive index changes when the concentrations of salt and sugar solutions are varied respectively. In Fig.1, it gives a sort of pattern that the refractive

  1. See how different concentrations of Hydrochloric acid change the rate of reaction with a ...

    I had stated this in my prediction. However I also stated in my prediction that if I doubled the concentration from 1M to 2M hydrochloric acid then the rate of reaction will also double. I have discovered that this is not the case because if the concentration is doubled then there are twice the many acid particles,

  2. Investigate how the concentration of 10 ml of hydrochloric acid affects the rate of ...

    will collide so increasing the reaction rate. When hydrochloric acid (HCl) is added to calcium carbonate (CaCO3) the two substances react giving this equation: CaCO3 + 2HCl � CaCl2 + H2O + CO2. This shows that when the two react, calcium chloride, water and carbon dioxide are all given off and the gas that fills the measuring cylinder is CO2.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work