Question

activity c: intermolecular forces
get the gizmo ready: select the intermolecular forces tab.
introduction: the polarity of molecules give rise to the forces that act between them. these intermolecular forces, or imfs, affect many physical properties including boiling point, solubility, viscosity, and surface tension.
question: how does polarity affect the forces between molecules?

1. observe: select the show polar molecules inset checkbox. what do you notice?

each polar molecule is known as a dipole. the attraction between the positive end of one dipole and the negative end of another is called a dipole - dipole force.

1. observe: turn on the show nonpolar molecules inset. what do you notice?

even when the molecules are nonpolar, random variations in the distribution of electrons can cause parts of these molecules to become slightly charged. this imbalance leads to very tiny, short - lived attractions between molecules called london dispersion forces.

1. experiment: turn off show polar molecule inset and show nonpolar molecule inset. drag two h₂o molecules into the simulation area, and click play. click pause ( \ \) when you see an attraction (dotted line) form between molecules. sketch the molecules, partial charges, and the attraction between them in the space to the right.

why is a hydrogen atom in one h₂o molecule attracted to the oxygen atom in an adjacent h₂o molecule?
drag the h₂o - h₂o molecule combination into the correct bin on the right. which type of intermolecular force causes attraction between h₂o molecules?

Explanation:

Step1: Observe polar molecules

When the "Show polar molecules inset" checkbox is selected, we can see that polar molecules have a separation of positive and - negative charges, forming dipoles.

Step2: Observe non - polar molecules

When the "Show nonpolar molecules inset" is turned on, we notice that non - polar molecules have random variations in electron distribution causing temporary charges and weak London dispersion forces.

Step3: Analyze water molecule attraction

In water ($H_2O$), oxygen is more electronegative than hydrogen. The oxygen atom in one $H_2O$ molecule has a partial negative charge ($\delta-$) due to its high electronegativity, while the hydrogen atoms have partial positive charges ($\delta+$). The hydrogen atom in one $H_2O$ molecule is attracted to the oxygen atom in an adjacent $H_2O$ molecule because of the electrostatic attraction between the $\delta+$ hydrogen and the $\delta-$ oxygen. This type of intermolecular force is a hydrogen bond.

Answer:

1. Polar molecules form dipoles with positive and negative ends.
2. Non - polar molecules have temporary charges due to electron distribution variations, leading to London dispersion forces.
3. The hydrogen atom in one $H_2O$ molecule is attracted to the oxygen atom in an adjacent $H_2O$ molecule because oxygen is more electronegative, creating partial charges. The intermolecular force between $H_2O$ molecules is hydrogen bonding.