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

Assess the effect of concentration of sodium thiosulphate in the acid/sodium thiosulphate reaction

Extracts from this document...

Introduction

Chemistry Coursework Plan In this project, I am trying to assess the effect of concentration of sodium thiosulphate in the acid/sodium thiosulphate reaction as follows: - Sodium thiosulphate + hydrochloric acid ==>Sodium Chloride + Sulphur + Sulphur dioxide + water Or Na2S2O3+2HCl ==>2NaCl + S + SO2 + H20 Some of these chemicals are hazardous unless handled correctly - here is a safety table of the substances I am using:- Chemical Hazard Procedure Sodium Thiosulphate - Na2S2O3 * Harmful if ingested in quantity * In reactions with acid - Sulphure dioxide is produced. * Ventilate room Hydrochloric Acid - Hcl * Corrosive * Irritant * May cause burns * Vapour is very irritating to the respiratory system * Wear protective clothing * Ventilate room Sulphur Dioxide - SO2 * Irritant to respiratory system * Noctious gas * Ventilate room Sodium Chloride - NaCl * Irritant * Harmful if ingested in quantity * If contact with skin occurs, wash thorugly. Sulphur - S NO HAZARD N/A Water - H20 NO HAZARD N/A To do this I am attempting to measure the speed (time period) in which it takes the colloidal effects of the reaction to reduce visibility of a black cross marked underneath. In order to start the experiment, I will need the following apparatus: - * Conical flask * 10ml + 100ml Measuring cylinders * A4 paper (white) ...read more.

Middle

1-3oc). The same person will always look at the cross to ensure consistency when observing. I am choosing to use measuring cylinders to measure liquid volumes in this experiment as I feel beakers are too inaccurate and none of the small size required are available. Measuring cylinders are the right size, and have appropriate intervals between markings to allow precision when using the liquids. I am also not using pipettes as I do not need the reverse to the above; acutely small amounts. A pipette would rather hinder, than help my experiment by increasing the time required to set up each experiment as I have found with previous experiments involving small measurements. I shall repeat each experiment three times so as to get an average and make the results fair. Prediction I think that as the concentration of sodium increases, the time taken for the cross to become indistinguishable will diminish exponentially as this graph shows: - I think this will happen because the particles in the liquid will have a larger chance of coming into contact with one another and creating colloidal sulphur that will block the view of the cross by reflecting light. Colloids are created during the reaction. A colloid is halfway between a solution and a suspension. In a colloid, particles of matter measuring between about one-millionth of a millimetre and one-tenth of a millimetre in diameter are evenly scattered throughout liquid or gas. ...read more.

Conclusion

This was because a more concentrated liquid has a larger ratio of particles to water. This meant that the acid molecules were more likely to come into contact with the sodium, and therefore create a greater rate at which colloids were produced. We had anomalous results as we had to change our cross after the first five experiments, which changed the time scale. Also, the judging by eye technique was inaccurate and crude. We could not add the liquids together evenly (only by pouring), and the timer was started at small discrepancies with when the liquid was mixed. Also, not all of the acid and mixed liquids came out of the beakers, making it more inaccurate. We could have improved it greatly by using a photosensitive diode to measure colloidal opacity and a computer-controlled timer would have enhanced our readings. Another way of combing the liquids evenly and without having to use physical means (for instance, a Y tube design with holders at the top would have kept time discrepancies to a minimum. Also, greasing/cleaning the equipment thoroughly would stop droplets of liquid clinging to the Pyrex containers. We had results to confirm our conclusion, as the points were relatively straight and 80-90% on the line of best fit. A way to work out reaction time by mathematical means would have been a benefit, cutting out any practical experiment, and eliminating any chance of odd results. ...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 Patterns of Behaviour 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 Patterns of Behaviour essays

  1. Marked by a teacher

    Chemistry Coursework - How the concentration effects the rate of reaction between sodium thiosulphate ...

    All of the information that I have just provided can be said exactly the same for the results table two. They both follow a set pattern where as the concentration of the thiosulphate decreased, the rate of reaction decreased and the time for the reaction increased.

  2. Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid Coursework

    Fair Test To make this experiment a fair test, we need to make sure we do a number of things. In this experiment we are trying to find the rate of reaction using concentration as a factor, so there is a number of things we need to make sure we do to keep it a fair test.

  1. The reaction between Sodium Thiosulphate and Hydrochloric Acid.

    The vapour from it is very irritating to the respiratory system. Solutions greater than 6.5 moles are corrosive and those greater than 2 moles are irritant. When hydrochloric acid is mixed with aluminium, magnesium, calcium, sodium, phosphoric (V) acid and sulphuric acid, a vigorous reaction occurs and hydrogen chloride gas is released.

  2. Investigating the reaction between Sodium Thiosulphate and Acid.

    With this reaction in particular, the following methods can be used to judge how fast the reaction is: * By measuring the volume of gas produced (i.e.: the sulphur dioxide produced by the effervescence of the reaction). * By measuring the mass of the reaction lost (i.e.: when sulphur dioxide gas is given off from the reaction).

  1. To see the effects of a change in temperature and concentration on the rate ...

    The experiment is repeated using all the temperatures. The entire procedure is the repeated. Repeat results and averages will be taken to improve the credibility of the findings, and present solid grounding for the final conclusion. The repeat results will help to iron out any anomalies and the average will give a good summary of the results of the experiment.

  2. Find out the effect of concentration on the reaction between Sodium Thiosulphate and Hydrochloric ...

    When you increase the pressure the molecules have less space to move around. That greater concentration makes them collide with each other more often. When you decrease the pressure molecules don't hit each other as much and there are fewer collisions.

  1. The Effect of Concentration on the Reaction of Sodium Thiosulphate with acid

    This obscures a piece of paper with a black cross written in indelible ink, which is placed underneath the flask. The clock is started when the two substances first interacted and then stopped when the cross beneath is completely obscured.

  2. Effects of Concentration of Sodium Thiosulphate in the reaction of Hydrochloric Acid and Sodium ...

    The collision theory states that for a reaction to take place between reacting particles (in this case ions) it is necessary for them to collide. Furthermore they must have sufficient energy to react otherwise they will simply bounce off each other.

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