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

Determining the relative atomic mass of lithium

Extracts from this document...


Assessed practical- Determining the relative atomic mass of lithium o Hazards of chemicals used and obtained: Method 1- 2Li(s) + 2H2O(l) � 2LiOH(aq) + H2(g) Method 2- LiOH(aq) + HCl(aq) � LiCl(aq) + 2H2O(l) In method 1 hydrogen gas is produced. This is flammable and although not a lot will be produced it would be safe to keep the product away from open flames, sparks, etc. The product of the second method, lithium hydroxide, is alkaline and an irritant. When handling it care should be taken and if it is spilt all of it should be cleaned up immediately. Although not hazardous to us the lithium is very reactive and is used in small quantities. Also precaution must be taken in order to get accurate results, as with the distilled H2O that may become contaminated. In method 2 hydrochloric acid is used and although it only has a concentration of 0.1mol dm-3 care must be taken so it isn't spilt or brought into contact with skin, as it is an irritant. ...read more.


So; moles of HCl used in the titration = concentration � volume = 0.1000mol dm-3 � 36.03 dm3 1000 = 3.603�10-3 moles As 1 mole of LiOH reacts with 1 mole of HCl, [LiOH(aq) + HCl(aq) � LiCl(aq) + 2H2O(l)] then 3.603�10-3 moles of LiOH were used in the titration. Only 25cm3 of the LiOH solution at a time during the titration, so the number of moles in the 100cm3 solution from method one = 4 � 3.603�10-3 = 0.0144moles. Therefore, the relative atomic mass of lithium = moles = 0.1000g = 6.94g mol-1. 0.0144dm3 o Evaluation: Overall my results are quite accurate and in the case of method two correct, when rounded to three significant figures. In my calculations I used four significant figures in order to improve accuracy, and by using the average of three titrations (all within one decimal place of each other) ...read more.


Ideally a polarized, un-reactive solution should be used instead. Another measurement error is the resolution of the apparatus used; the scales measured to the nearest 10mgram, the burette measured to the nearest 1cm3 whilst the measuring cylinder to the nearest 2cm3. With a higher resolution method two will have more accurate results. The most significant measurement error is the amount of gas given off in method one. Aside from the procedure the measurement can be modified to reduce the error: H2 gas produced = 172cm3 � 1cm3 (as the resolution is to the nearest 2cm3). Minimum possible value: 171cm3. Relative atomic mass of lithium: 171/24000 = 7.125�10-3moles. 7.125�10-3 � 2 = 0.01425moles. 0.1/0.01425 = 7.02g mol-1(3s.f). Maximum possible value: 173cm3. Relative atomic mass of lithium: 173/24000 = 7.208�10-3moles. 7.208�10-3 � 2 = 0.0144moles. 0.1/0.0144 = 6.94g mol-1(3s.f). ROB HENDERSON ...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. How much Iron (II) in 100 grams of Spinach Oleracea?

    present in 100 grams of Spinach. This is not the expected result of 4 mg's, which is what the many textbooks suggest the answer should be, but the results of this experiment are getting closer to the expected value suggesting that my modifications are working.

  2. Determination of the relative atomic mass of lithium.

    To improve the accuracy of my results the room temperature should be checked. Because, if the temperature is not standard, one mole of the hydrogen would not take up 24dm3, which would make the calculations inaccurate.

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

    These improvements will minimise the significant sources of error as it excludes the previous errors that might have been made. Smaller divisions in measuring apparatus mean that if errors are made then they will be to a smaller percentage error.

  2. Determination of the relative atomic mass of Lithium

    Evaluation As you can see from the results looking at the rough titration, you can identify there were slight errors. The errors may have occurred in the procedure of the experiment, as first of all there were a few variables that could not be controlled such as the temperature was approximately 25 C and the pressure was standard.

  1. Determination of the Relative Atomic mass of Lithium

    I have also gained the results of all my classmates and so I can use their data compared to mine, and I can also use this data to show how far away I / the class were from the actual RAM of Lithium.

  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

    time to obtain an average > I will use the same equipment each time > Values should also be read at eye level to ensure that the correct value is being seen, viewing from other angles can cause the incorrect value to be seen.

  2. To find the relative atomic mass of a sample of Lithium.

    >25 cm3 Pipette. >Pipette filler. >Water bowl. >Conical flask. >Boss clamp and Stand. >White tile. >Beakers. >Small pipette. >Distilled water dispenser >250cm3 Measuring cylinder. >Delivery tube. >Phenyl Phthalein. Method 1 Carry out the method set out for the first Experiment being careful to follow the instructions carefully.

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