Our small and how polarizable a molecule is.

Our purpose and guiding question for this investigation  was “how does the surface tension and relative intermolecular forces compare between certain substances? “. Starting with the basic, intermolecular forces are the forces between molecules, they are important because they can help the scientist to have a predict on the bond strength between atoms in a compound,  they also indicate the strength, how big or small and how polarizable a molecule is. An example of intermolecular forces is washing your hand with soap, when the soap gets between the intermolecular forces of the water molecules, it will reduce the surface tension. Talking about surface tension, it is the inward force, or pull, that tends to minimize the surface area of a liquids. There are 3 intermolecular forces that are related to this experiment: Hydrogen Bond, London Dispersion Forces and Dipole- Dipole. Hydrogen bond is a type of Dipole- Dipole, it occurs between a Hydrogen that is covalently bonded with F,O,N,and Cl with at least one lone pair. It is so strong because the F-H, O-H, N-H, AND Cl-H bonds are very polar. These atoms here are small, so the partial charges that were caused by the electronegativity is very high focus. London Dispersion Forces are basically the only intermolecular forces that keep gather all the non-polar species together. Dipole- Dipole is the attraction forces between one negative end of a polar molecule to the positive end of another polar molecule. My hypothesis for the ranking of the intermolecular forces/surface tension of the substances was water: 1, Isopropyl: 2, Ethanol: 3, Methanol: 4, Acetone: 5, and Cyclohexane: 6. I predicted that water will have the most intermolecular force in all the of the substances. For example, water will sticks together better than Methanol because water have a really strong hydrogen bonding, it contains only O-H bonding which means oxygen is more electronegativity than hydrogen, meaning it has a higher tendency to attract other electrons. On the other hand, Methanol don’t have a strong hydrogen bonding, the strength of it is also not as strong as water. Another example, water and Ethanol, because Ethanol have a weaker hydrogen bonding than water. Ethanol is smaller molecule so they are less polarizable than water.

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