Aim: This experiment plans to measure the volume of one drop of water and compare it the volume of one drop of sodium chloride solution. What will be attempted by this experiment is to measure the volume of one drop of distilled water by measuring a control and comparing it the volume of one drop of distilled water with dissolved NaCl. This will be done by using a burette for dropping the distilled water and a electrolyte solution.
Hypothesis: I hypothesise that the volume of one drop of water will decrease as the concentration of NaCl increases. I believe this is due to the type of intermolecular bonding present and the different densities of salty and pure water. Water is held together by the strongest intermolecular force called hydrogen bonding. This bonding is then replaced by ion-dipole when salt is dissolved in the water which is a weaker intermolecular force compared to hydrogen bonding. "Generally speaking, Hydrogen bonding is stronger (20-40 KJ/mol) than ion-dipole (10-20 KJ/mol)" ("Chemicalforums") . The water is then not held together as tightly and less force is needed to separate one drop from the main body of water. It would therefore be expected that the volume of the drop would be less as the gravitational force on a substance is directly proportional to its mass, shown by the equation below .
F=(G〖m_1 m〗_(2 ))/r^2
G=gravitational constant m_1=mass of object 1. Which in this case is constant as it refers to the mass of the earth. m_2=mass of object 2. Which is the mass of the drop r^2= the distance between the objects.
F= gravitational force
Therefore if the force to separate the water is less the gravitational force needed for a drop of water to fall would be less, this then means the mass of the drop would then be less as all other variables are kept constant. Also due to the fact that salty water is more dense than pure water it would mean that the
Bibliography: Albert. "Ion Dipole Dipole vs. Hydrogen Bonding." Chemicalforums.com. Mitch André Garcia, 23 Sept. 2011. Web. 27 Jan. 2013. . Chang, Muncel. "Salt Water vs. Fresh Water." About.com. N.p., 19 Sept. 2000. Web. 27 Jan. 2013. .