Experiment To Investigate The Resistance Of Brine

Soaked Paper Essay, Research Paper

This

experiment aims to investigate the resistance of brine soaked paper when an

electrical current is passed through it. Planning: ?Previous experiments have taught me that the

electrical resistance will rely on several key variables.? These include the length of paper, its

thickness but most importantly the number of sodium and chlorine ions carrying

the charge.? Knowing this, I have

decided to investigate the concentration of brine in this experiment.? To provide an accurate prediction, I must

research into the scientific details in this experiment and recall information

from previous investigations.? This will

give me a greater understanding of the experiment?s implications and likely

results.Ionic

compounds do not have a molecular structure, but form a three-dimensional array

of ions called a crystal lattice.? In a

crystal of sodium chloride, the ions are arranged so that each Na+ ion is

surrounded by six Cl- ions and

vice versa.? Because the ions are held

rigidly in place by the electrostatic attractions between any one ion and the

oppositely charged ion surrounding it, these compounds tend to be very

brittle.? They do not conduct electricity

when in a solid state, since the ions are not mobile.? However, when in solution or in the molten state, ionic compounds

will conduct electricity by the movement of ions.In this

investigation, two electrodes will be placed on paper soaked in brine and an

electrical current will be applied.? The

sodium chloride is in a solution with water so that the ions are free to

disassociate.? The sodium ions should

migrate to the negative electrode and the chloride ions migrate to the positive

electrode, causing an electrical current to flow.? Having singled

out the most influential factor, and researched into the formation and

qualities of the sodium chloride compound, I have formed a prediction.? I predict that the higher the concentration

of sodium chloride in the brine solution, the lower the resistance.? This prediction is based upon the fact that

at a higher concentration, there will be more sodium chloride ions creating

lower resistance.Method: 1.?????? Connect the circuit,

ensuring that the voltmeter is in parallel with the brine soaked paper.To investigate

the resistance of brine soaked paper; I will set up an electronic circuit. I

will utilise a battery, variable resistor, wire, voltmeter and a milli-ammeter.

I am using a

milli-ammeter because the difference in current is likely to be minute and this

will give me a more accurate reading.? I

am using a variable resistor so that I can take several readings (repeating my

results) to form an accurate investigation. 2.?????? Measure out 10 ml of

solution in six test tubes.The salinity

will be varied by diluting a 1M solution of brine to different ratios of salt

to water. To obtain

accurate readings, the same amount of brine will be used for each result

(10ml).? This will be measured using a

measuring cylinder.? 3.?????? The paper will be placed

in a test tube of brine for the specific time of five seconds ensuring that the

paper is completely coated in brine.?

The paper will only be soaked for a specific time because over a longer

period paper will absorb a greater amount of liquid.? By controlling the time, I can create a fairer experiment.The amount and

type of paper will be identical for each reading.? I will use a 6×2 cm rectangular sized piece of paper.? If I used differing sizes of paper then my

results would be inaccurate as more brine could be absorbed or the greater

amount of paper would create a higher resistance.? 4.?????? The brine soaked paper

will be connected into the circuit using crocodile clips.? To prevent contamination or loss of brine,

forceps will be used to transfer the paper from the test tube into the circuit.5.?????? To discover the

resistance of the brine soaked paper; I will record the voltage and current at

each concentration repeating each reading three times and then formulate the

resistance using the formula:Resistance = Voltage ?????????????????? ?? CurrentI will then

take the average of my readings to ensure accurate results and reduce the

effect of any inaccuracies.Obtaining Evidence/Analysing Evidence ?And Drawing Conclusions: I have

tabulated the results of the experiment so that any patterns will become more

apparent and I can distinguish whether my hypothesis was correct.? The concentration column in the table states

the percentage of brine as opposed to water used to test each reading.? 1. Concentration Current Voltage Resistance 2. Concentration Current Voltage Resistance After taking

these readings, I realised that although both tables 1 and 2 show a similar

trend, the actual figures are very different.?

They vary from a resistance of 468 ohms at one reading to 235 ohms at

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