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

Conductivity Lab. Purpose: To determine which substances are ionic and which are molecular based on their ability to conduct electricity

Extracts from this document...

Introduction

Conductivity Lab Purpose: To determine which substances are ionic and which are molecular based on their ability to conduct electricity Materials: Conductivity tester - 15 solutions w/ dropper and microplates Background: **When ionic substances dissolve in water, the ionic bonds break and the ions separate from each other. When most molecular substances dissolve in water, they remain in molecular form. However, some molecular compounds ionize in water. For example sugar dissolves in solutions but does not dissociate. ***Basically, if you drop an ionic compound in water, the compound separates into free ions. Molecular compounds do not usually separate into ions. Prelab Questions: 1. What is the difference between a cation and an anion? A cation is a positive ion while an anion is a negative ion. 2. What is the difference between an ionic compound and a molecular compound? An ionic compound is a compound with a metal and a nonmetal bonded together while a molecular compound is nonmetals bonded together. Also, ionic compounds dissociate while most molecular compounds don't 3. What does it mean when something "dissolves" in water? ...read more.

Middle

Place 15-20 drops of 5 different solutions in the microplate 2) Write the formula or name of each solution in the microplate in the data table 3) Dip the electrodes into the first well. 4) Wait until the numbers on the multimeter stop moving. Record conductivity 5) Rinse electrode with distilled water and wipe off electrodes with tissues. 6) Repeat for the other 4 solutions in the microplate 7) Rinse the microplate and get 5 more solutions. 8) Repeat until 15 solutions have been tested. Error Analysis Sources of error that may have given an inaccurate conductivity of a solution in this experiment are different placements of the electrodes, misreading the numbers on the multimeter, dirty electrodes, and different kinds of multimeters. Examples: Different people place the electrodes in different places. If the electrodes are closer together than the resistance level would decrease while when they are farther apart the resistance level would increase. People misread the numbers on the multimeter because they look at it with different angles. The multimeter could also show the arrow in the middle of two numbers, so people would have to guess the number in the middle. ...read more.

Conclusion

The compounds that produced the most ions have the best ability to conduct electricity. 5) Tap water was able to conduct while distilled water was not. The tap water could conduct because it has ions that give it that ability while distilled water does not. Tap water could be mixed with substances that give it the ions. 6) The prediction that salt water would be able to conduct turned out to be correct because the salt when melted separated into ions and gave the water two different charges making it able to conduct. The ions were Na+ and Cl-. The prediction that distilled water would conduct electricity proved to be incorrect because it does not contain ions that give it the ability to conduct electricity. This was a surprise because most people think that distilled and tap water are almost alike. 7) People would get electrocuted if they went swimming in a pool during an electrical storm because the pool can conduct electricity due to the chlorine added to the water. The water now contains different charges of ions. 8) Athletes drink Gatorade to increase their energy. It has electrolytes that make it able to conduct electricity giving them extra energy. It containing electrolytes mean that the solution has ions. ...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

Here's what a teacher thought of this essay

4 star(s)

This is a good account of conductivity. It contains a well through out experiment to confirm whether a broad range of materials conduct. The report does not go into much detail about why certain things do or do not conduct.

Marked by teacher Brady Smith 17/06/2012

Here's what a star student thought of this essay

3 star(s)

Response to the question

The candidate has carried out a well-planned experiment to investigate the conductivity of different substances. They made hypothesis, and then measured the conductivity of each substance to prove or disprove their hypothesis.
Their report doesn't explicitly give a conclusion, ...

Read full review

Response to the question

The candidate has carried out a well-planned experiment to investigate the conductivity of different substances. They made hypothesis, and then measured the conductivity of each substance to prove or disprove their hypothesis.
Their report doesn't explicitly give a conclusion, but instead has a 'digesting the data' section (a better word would be 'analysis'!) which leaves the reader to refer back to their hypothesis to discover their conclusion. Although they have investigated the question well, they have failed to fully answer it in a well-balanced conclusion.
is very good.
3*

Level of analysis

When making their hypothesis, the candidate failed to think logically about the structure of the substances, which meant that their hypotheses were unsupported and sometimes incorrect - for example claiming that distilled water would conduct because 'it probably has the same properties as tap water' - tap water apparently conducted because 'it is a common saying'. hypothesis need balanced scientific reasoning. however, they have used a more logical explanation of the properties of the substances when analysing their results - this section is fairly well written and detailed. However, they could improve by explicitly stating that dissociation is the breaking of an ionic bond, which allows the ions to be dissolved into the solution and so conduct electricity (they could also have discussed that the dissociation is caused by the attraction of the ions to the water molecules). They have, however, implied this several times, particularly when analysing the differences between ionic solids and solutions.
They have also analysed how well they carried out their experiment, but looking at causes of uncertainties and how these would have affected the results - this explanation is particularly good. They could have developed this section further if they had repeated their experiment - by finding the mean of the data, as well as identifying outliers. Despite this, their analysis is very good.

Quality of writing

Their spelling and grammar is generally very good. However, there is room for improvement in the layout of the report - particularly in their choice of subtitles. The subtitles 'Data table' is particularly misleading, as it implies that it has been sound from another source. It would have been better to use the subtitle 'results'. This section should also have been placed after the description of the method (which needs a labelled diagram). A major problem is the lack of a conclusion - the candidate has left it up to the reader to look at their analysis of results (the conclusion is 'hidden' within the analysis section). It is very important to have a separately headed conclusion section for clarity. Despite these issues, they have described their reasoning very well and precisely, which is very good.


Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by dragonkeeper13 29/06/2012

Read less
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

    The aim of the experiments was to test food samples to see which food ...

    4 star(s)

    Give the test solution a gentle shake 4. Observe changes The Emulsion Test 1. Put about 2cm3 of the lipid sample into a test tube 2. Add 4cm3 of ethanol into the test tube using a pipette 3. Decant the lipid sample with ethanol into a test tube of water 4.

  2. Marked by a teacher

    My aim for this experiment is to investigate the solubility of salt

    4 star(s)

    2 5.7 3 5.9 Ave 5.7 Temp of water 40 Celsius Expt Mass of salt dissolved 1 6.7 2 6.6 3 6.8 Ave 6.7 Temp of water 50 Celsius Expt Mass of salt dissolved 1 13.1 2 8.2 3 8.1 Ave 8.15 I have chosen to ignore this because it is an anonymous result.

  1. Titration Experiment

    If the solution turned yellow, then you have had added too much acid. Add 1 cm3 of sodium hydroxide, using a graduated pipette, then retitrate, adding one drop at a time of hydrochloric acid. Results For my titration practical I had 3 results, from which I worked out an average result.

  2. To investigate three factors that affect the rate of cooling a liquid and to ...

    55?C 54?C 52?C 720 seconds 54?C 52?C 49?C Analysis Experiment 1 From looking at the results from experiment 1, I can see that my prediction was indeed correct. I predicted that the beaker with no insulation would cool the quickest and the woollen lagging would take the longest to cool.

  1. Determine Solubility of KClO3 Salt.

    Supersaturated solutions are unstable. When prepare for crystallization, the molecules or ions of solute must arrange themselves properly to form crystals. The unit we been use for solubility in this experiment is gram/100-mL. There are many kinds of units to describe how much solute we have in a solvent.

  2. Determining the iron content in a sample of steel wool.

    Repeat the titration in the usual way 16. Pipette 20ml of the iron (II) sulphate solution into a conical flask and about 10ml of dilute sulphuric acid and titrate with standardized KMnO4 solution.

  1. Separation Of A Mixture of Salt, Sand and Iron Filings

    Filter paper 5. Funnel 6. Beaker 7. Stirring rod 8. Magnet 9. Distilled water Method: 1. Salt, sand and iron filings were mixed together in a bowl. 2. A magnet was run through the mixture to pick up the iron filings.

  2. AIM: To study the effect of solid impurities on boiling point of water and ...

    The elevation of boiling point of a solution is equivalent to the product of the number of moles of solute dissolved in 1kg of solvent (molality) and a constant of proportionality, Kb known as Boiling Point Elevation Constant or Molal Elevation Constant (Ebullioscopic Constant)

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