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

I aim to investigate the rate and mechanisms of the reactions between magnesium and acids.

Extracts from this document...


PLANNING Aim I aim to investigate the rate and mechanisms of the reactions between magnesium and acids. Introduction The reactions I will investigate are nitric acid with magnesium, and sulphuric acid with magnesium. I will vary the concentration of nitric and sulphuric acid in separate experiments, and I will vary temperature in order to study what effect these variables have on the rate of reaction. The mass of magnesium used will remain constant. My experience in chemistry suggests that the rate will increase with both concentration of acid and temperature, the exact relationships will be investigated. The variation of rate can be described by the rate equation, specific for each reaction. The rate equation must be found by experiment rather than predicted by theory, it takes the form: Rate = k[A]x[B]y where the square brackets indicate the concentration of the substance indicated inside them, the x and y indicate a power that this concentration is raised to and k is the rate coefficient. The rate coefficient is constant at a constant temperature, and its variation with temperature is described by the Arrhenius equation: k=Ae(-E/RT) where E is the activation enthalpy, R is the molar gas constant, T is the temperature and A is a constant. ...read more.


Note that the sodium hydroxide was added rapidly as soon as the time period had elapsed. This whole process was then repeated with different concentrations of nitric acid, all other variables are constant. The nitric acid was diluted from its original 2M by the table below. The entire process was then repeated with sulphuric acid in place of nitric acid. Then the whole experiment was repeated at 50�C. This was achieved by placing all reactants; acid, sodium hydroxide and magnesium in separate boiling tubes and submersing them in a water bath set at 50�C. There they were left to heat for five minutes, and then the acid added to the magnesium and the boiling tube placed back in the water bath. The titration was performed as before. Dilution Table Start with 2M nitric or sulphuric acid, depending on experiment. Always make up to 20cm3. Water used is distilled water. 2 M 20cm3 acid 1 M 10cm3 acid, 10cm3 water 1.75 M 17.5cm3 acid, 2.5cm3 water 0.75 M 7.5cm3 acid, 12.5cm3 water 1.5 M 15cm3 acid, 5cm3 water 0.5 M 5cm3 acid, 15cm3 water 1.25 M 12.5cm3 acid, 7.5cm3 water 0.25 M 2.5cm3 acid, 17.5cm3 water Risk Assessment Clearly I will be dealing with strong concentrated acids and alkalis and so care must be taken not to allow contact with skin or eyes. ...read more.


Fewer, in fact half, as many moles of sulphuric acid will react with the same amount of magnesium as nitric acid, due to the ratios of the reactions below: Mg + 2HNO3 ==> Mg(NO3)2 +H2 Mg + H2SO4 ==> MgSO4 +H2 HNO3 + NaOH ==> NaNO3 + H2O H2SO4 +2NaOH ==> Na2SO4 +2H2O EVALUATION Sources of Error The 10cm3 measuring cylinders used to measure out the volumes of acid and base were accurate to �0.1cm3. The burette used in the titration was accurate to �0.05 cm3. There is human error involved in judging the end-point of the titration, though I chose methyl red as my indicator as it gives a very clear colour change and was very careful in my method it is possible that I did not measure the exact end-point. It is also likely that such an error would not be systematic and so could affect the results randomly. Improvements If I were to perform this investigation again with unlimited resources, I would first use larger quantities of all reactants in order to reduce possible error and to make conclusions firmer. I would investigate a wider range of acids, acid concentrations and temperatures in order to draw firmer conclusions about the trends and relationships I have identified. 1 Page ...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 investigate the effect of temperature on the rate of reaction

    4 star(s)

    Varying time intervals Using 10 seconds as a time interval for small chips and then 5 seconds as an interval for the small chips does not help us compare easily, and therefore lowers the accuracy of our final results.

  2. The rate of reaction between magnesium and sulphuric acid.

    Amount of H? 30 46 4 cm3 60 39.5 10.5 cm3 90 33 17 cm3 120 28.5 21.5 cm3 150 24.3 25.7 cm3 180 22.3 27.7 cm3 13ml of Acid: 7ml of Water Time measured in seconds Reading on burette (ml)

  1. Determination of Partition Coefficient

    Since the Kd measured from only one set of data is unreliable, 12 sets of data are collected from other classmates as follows: Expt. No. Mass of Acid Used / g [Acid(aq)]eqm / M [Acid(ether)]eqm / M Kd 1 0.7 0.209 0.0285 0.1364 2 0.217 0.0292 0.1346 3 0.196 0.0200

  2. Science Investigation Report - Aim To investigate how the voltage of the electric ...

    if the time changes, the charge of the electric current would be affected, causing the results to be invalid as only the current is supposed to be the only factor affecting the charge of the electric current. If the charge of the electric current is affected, the mass of copper

  1. In order to find out the exact concentration of sulphuric acid, I will have ...

    This means that the most suitable indicator to use was methyl orange. Even though the colour change was quite obvious during each titration, it was almost impossible to tell the exact amount acid which has to be used to make sure that the colour change was 100% correct.

  2. The aim of this investigation is to discover if different variables affect the rate ...

    * When the agar is in acid I will start a stopwatch and record the time accurately. * I will continue to do this with different concentrations of acid. * I will record each 5 times to get a fair result and average.

  1. To investigate the differences in order of reaction and activation energy of the reactions ...

    [A] = concentration of substance A in mol dm-3) The indeces a and b are the order of the reaction with respect to the corresponding substances A and B respectively. The overall order is the sum of these. (In this investigation I will try to find out the order

  2. Determine the Enthalpy of Neutralisation for the following there Acids, H2SO4, HNO3 and H2SO4

    I will carry out the neutralisation reaction in the cup and taking regular temperature readings. Use this to plot a Temp vs time graph. By extrapolating the graph find out the temperature rise use this and the E= mc?t to calculate the energy released to the water and hence deduse the enthalpy of neutralisation.

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