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

Determination of the relative atomic mass of lithium

Extracts from this document...

Introduction

AS Assessed Practical Determination of the relative atomic mass of lithium Results - method 1 Mass of lithium used - 0.10g Volume of hydrogen evolved - 188.00cm Results - method 2 Rough Accurate 1 2 Initial volume reading (cm�) 0.00 0.00 0.00 Final volume reading (cm�) 34.69 34.98 38.94 Volume used (cm�) 34.69 34.98 38.94 Average volume of Hydrochloric Acid used = 34.98 + 34.94 / 2 = 34.96 cm Calculations - method 1 2Li + 2H2O 2LiOH +H2 2 moles 1 mole 1 mole of gas occupies 24000cm� at RTP Volume of H2 gas evolved = 188cm� 188 / 24000 = 0.0078 moles 0.0078 2 = 0.016 moles (2sf) Ar = 0.10 / 0.016 = 6.383 (3dp) ...read more.

Middle

The final result of the atomic mass is then affected by 5% which could have been 6.383 plus or minus 0.31915. * Another factor that could have affected the results is the time delay between putting the lithium in the solution and putting the bung on. Hydrogen could have escaped during this delay causing approximately a 1% error in the results. Therefore, altogether, procedure one could have a maximum of a 6% error within the results. Procedure 2 however is slightly more accurate because using a burette is much more accurate with only a possible 0.1cm error which is an approximate 0.28% error. This gives the procedure a possible total of 5.28% plus or minus of the final result. ...read more.

Conclusion

To overcome the delay in the time the lithium is put in the solution and the time the bung is put on the conical flask, a shelf like product could be attached already inside the conical flask so that the lithium could be placed on this and then simply shook off when you are ready to begin the experiment. This will prevent any hydrogen from escaping in the time it takes to put the bung on. To overcome the inaccuracy of weighing the lithium (apart from using a more accurate scales) a larger mass could be used for the experiment as this would produce a smaller percentage error because e.g. 5 % of 1.00g is far less than 5% of 0.1g. If all of these factors were changed, it would improve the overall accuracy of the experiment and the reliability of the results. Kimberley Davies 7410 AS Chemistry assessed practical 53621 ...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. Determination of the relative atomic mass of lithium.

    I will then remove the stopper on the conical flask, add the lithium and quickly replace the stopper. 5. After the effervescence stops, indicating that the reaction is over, I will record the amount of gas collected in the measuring cylinder.

  2. Determination of the relative atomic mass of lithium.

    Thus this would add to the end result making an error. This factor will affect the result by only a minute amount. This is because if the bubbles did enter the cylinder and they were big enough to notice, then I would have started again.

  1. Determination of the Relative Atomic Mass of Lithium

    As the results are averaged, without the anomalous ones, they move closer towards the real value of the Ar of lithium. Evaluation On the whole, both experiments went exceptionally well. Most of my results were as I expected and I observed extreme safety throughout the experiments because we were using

  2. to determine the relative atomic mass of lithium. We will be doing this via ...

    This is where percentage errors come in. The reading error is the most significant source of error as it is quite easy to misread a reading of volume or any other measurement, and sometimes it is guesswork when the reading is situated between two values.

  1. Determination of the Relative Atomic mass of Lithium

    Method 1 (Gas Syringe) Method 2 (Titration) Chris 10.79 05.02 Mike 11.06 09.59 Kavit 09.40 09.02 Dipen 13.60 10.50 Arjan 12.56 07.64 Raif 11.05 08.64 My Result 10.11 08.50 Matt 14.03 09.44 From these results I will calculate the class average excluding my own results: Method 1: 82.49 / 7

  2. Determine the relative atomic mass of lithium.

    + HCl(aq) LiCl(aq) + H2O(l) Method 1 : Apparatus 1 x Measuring cylinder (250cm�) 1 x Conical flask (250cm�) 1 x Rubber bung 1 x Tube 1 x Container 1 x Electronic scale 1 x Distilled water 1 x Lithium 1 x Goggles 1 x Gloves 1 x Lab coat The apparatus should be set up like this - Method 1.

  1. Investigation to determine the relative atomic mass of lithium

    lithium hydroxide solution and put it into a clean 250cm3 conical flask. I filled the burette with HCl making sure that the tap is closed. I then rinsed out the burette by opening the tap and allowing the HCl to run, this will release any air bubbles and will also clean the tip of the burette.

  2. The determination of the relative atomic mass (Ar) of lithium.

    Conical flask * Funnel * 10cm3 pipette Diagram Method 2 * Begin by washing out the burette, funnel and pipette with water and also the solution that will be passed through.

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