Determination of Avogadro's Number

Overview

Objectives/Goals Create a monolayer of oleic acid. Calculate total number of moles of acid by using measured volume and known concentrations. Calculate Avogardo's number by dividing the number of molecules by the number of moles. Methods/Materials Oleic Acid(C18H34O2), watch glass, micro pipette, bottled water, Isopropyl Alcohol 99%, chalk dust, 25ml beaker, plastic gloves, face mask, timer. Investigation One: Diluting Oleic Acid The goal is to achieve a solution that is 1% oleic acid in 25 ml. There are one million micro liters in a liter and one thousand micro liters in a ml(using formula M1V1=M2V2). Investigation Two: Time for Alcohol to Evaporate Determine the time between drops on a water surface, so that the alcohol has time to evaporate. Investigation Three: Determine Avogadro's Number(dividing total number of molecules by total number moles in the layer). Results Estimated Value of Avogadro's number: 5.0 x 1019 Percent Error: 99.99% Information needed: density of pure oleic acid(g/cm3), number of moles, volume of acid in layer, thickness of acid monolayer, number of molecules(assuming acid occupies cubical space). Avogadro's number is the number of particles in exactly one mole of a pure substance. Avogadro's number is 6.022 1367 x 1023 and is rounded to 6.022 x 1023. Conclusions/Discussion Results of experiment were not accurate. The estimated value of Avogadro's number is 5.0 x 1019. Far from Avogadro's true number(6.022 x 1023). Percent error was high at 99.99%. Avogadro's ideas explain the relationship between mass and the number of atoms. Possible Mistakes: dilution of oleic acid too drastic, use of different solvent(for dilution), volume of drops used per trial, number of trials.

Competition history

• CSEF 2003 Chemistry · Entry S0506

Resources

• CSEF project summary ↗

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

• All Chemistry projects
• CSEF Chemistry projects
• Every CSEF 2003 project