Compounds and Molecules - AP Chemistry

The figure above represents ABABA packing which is hexagonal close packing.

SF4 has 6 electron domains coming off of it- 4 F molecules and 2 lone pairs of e–. This is an example of see-saw shape.

COH2:

:O:

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H—C—H

This is a trigonal planar molecule, which only has bond angles of 120o

π bonds occur when there is greater than a single bond (double or triple bond). The only compound listed with double bonds or greater is CO2, meaning it is the one that contains the most π bonds.

Butane has 13 sigma bonds. Ethane has 7 sigma bonds. Benzene has 12 sigma bonds. Lithium Hydroxide has 2 sigma bonds and water has 2 sigma bonds.

when a central atom of a molecule has 6 electron domains coming off of it (none of which are lone pairs of electrons), it is considered octahedral

Each p subshell can have a maximum of 6 electrons in it. Note that there are three p orbitals, denoted px, py, and pz. These orbitals represent the plane in space in which they reside.

LiOH displays ion-dipole IMF, H2O displays hydrogen bonding, and CO2 displays dipole-dipole. Ion-dipole is greater than hydrogen bonding as an IMf, and hydrogen bonding is greater than dipole-dipole.

For a unit cell, the corners count as 1/8 of a sphere and atoms completely within the unit cell count as 1. This gives us 1 yellow and 1 green sphere in the unit cell shown above.

The figure above represents ABCABC packing which is cubic close packing.

The figure above has 8 Zn atoms on the corners (counting as 1/8) and 6 Zn atoms on the faces (counting as ½). This gives 4 Zn atoms in the unit cell. The Sulfur atoms are completely within the unit cell and count as 1 each for a total of 4 S atoms. This gives the formula Zn4S4 which reduces down to ZnS.

An interstitial alloy has a smaller atom inserted into the unit cell, a substitutional alloy has another atom substitute for the main element, and a pure metal is only composed of a single atom type.

This is butanol. It is an alcohol; OH is the prime example of hydrogen bonding, which is the strongest intermolecular force.

Ionic bonds are the strongest type of bonds, followed by covalent bonds, hydrogen bonds, and lastly, van Der waals forces.

Ion-dipole forces are the strongest of the intermolecular forces.

Hydrogen bonding is a specific term for a particularly strong dipole-dipole interaction between a hydrogen atom and a very electronegative atom (oxygen, fluorine, or nitrogen). However, hydrogen bonds are still not as strong as ion-dipole interactions.

In order from strongest to weakest, the intermolecular forces given in the answer choices are: ion-dipole, hydrogen bonding, dipole-dipole, and Van der Waals forces.

Ionic bonding is stronger than any of the given intermolecular forces, but is itself NOT an intermolecular force. Ionic bonds are a permanent chemical connection between two atoms, whereas intermolecular forces as a more transient and temporary attraction between independent molecules.

Ionic and covalent bonds are not intermolecular forces;

Ion-dipole>hydrogen bonds>dipole-dipole>van Der Waals forces

IMF strength is in the order of ion-ion>h-bond>dipole-dipole>van der waals. Of the listed compounds there aren't any that display ion-ion IMF, and only ammonia has h-bonding, making it the one with the strongest forces.

Helium gas will have the lowest boiling point since it is a noble gas and the only intermolecular forces present are dispersion forces, which are the weakest. Acetone has a dipole, so dipole-dipole forces will be present. Water has a dipole and can also hydrogen bond, as can isobutyl alcohol. However, isobutyl alcohol is heavier than water, and will thus have the highest boiling point.

Ion-dipole forces are the forces responsible for the solvation of ionic compounds in aqueous solutions, and are the strongest of the intermolecular foces. Hydrogen bonding is the second strongest intermolecular force, followed by dipole-dipole interactions. London dispersion forces are present in all solutions, but are very small and the weakest of the intermolecular forces.

Noble gases are uncharged and do not have polar covalent bonds or dipole moments. The only force that could apply to them are dispersion forces.