chemistry ch 4 & 7

Arrange the following compounds according to increasing intermolecular forces. Place the compound with the weakest intermolecular forces at the top of the list.

1. CH4 2. C6H6 3. C8H18

Match each molecular formula with its correct geometry.

1. H2CO - trigonal planar geometry 2. COS - Linear geometry 3. So2 - Bent geometry 4. PH3 - trigonal pyramid

List the elements below in order of increasing electronegativity. (Place the most electronegative element at the bottom.)

1. K 2. Ge 3. As 4. Br

Rank the intermolecular forces with the strongest intermolecular force on the bottom and the weakest intermolecular force on the top.

1. London dispersion forces 2. Dipole-dipole interactions 3. Hydrogen bonding

Rank the bonds listed below in order of increasing polarity. Place the most polar bond at the bottom.

1. N-N 2. N-O 3. N-H 4. N-F

List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the bottom.)

1. Na 2. Al 3. P 4. S

List the atoms in order of decreasing electronegativity. (Place the lowest electronegativity at the bottom.)

1. O 2. S 3. Se 4. Te

Match each bond depiction with its correct description. Instructions

1. Solid line - a bond in the plane of the paper 2. A wedge - a bond in front of the plane of the paper 3. a dashed line - a bond behind the plane of the paper

Arrange the type of compound according to increasing boiling point, with the lowest boiling point on top and the highest boiling point on the bottom. Assume you are comparing compounds of similar size.

1. compounds exhibiting london dispersion forces 2. compounds exhibiting dipole-dipole interactions compounds exhibiting hydrogen bonding

match the indicated atom with its correct geometry

1. tetrahedral geometry 2. trigonal pyramid 3. trigonal planar geometry

List the molecular geometries in order of increasing bond angles. (Place the largest bond angles at the bottom.) Instructions

1. trigonal pyramid geometry 2. tetrahedral geometry 3. trigonal planar geometry 4. linear geometry

What are the bond angles in a trigonal planar structure?

120

What are the bond angles in a linear structure?

180

An atom with a tetrahedral shape is surrounded by ______ atoms or groups.

4

What are the bond angles in a trigonal pyramid geometry?

< 109.5

In order for a bond to be nonpolar, the difference in electronegativities of the two atoms is _____.

<0.5

In which of the following sketches is the dipole properly shown? (Select all that apply.)

A & D

Which of the following statements correctly describe the nature of a dipole? Select all that apply.

A dipole is generated when there is a significant difference in electronegativity between the two atoms in a bond. A dipole is a separation of charge.

Which of the following statements about molecular polarity are correct? Select all that apply.

A polar molecule must contain a polar bond. A nonpolar molecule can contain three polar bonds.

The strength of the intermolecular forces can affect the physical properties of a substance. Select all physical properties that are affected by intermolecular forces.

Boiling point Melting point

In the molecule shown, which of the following are in the plane of the paper?

C O of the OH group H

Which bonds listed below are nonpolar? Select all that apply.

C-C C-S F-F

In which of the following bonds will the δ+ be drawn on the carbon?

C-F C-O

Correctly match each compound with the intermolecular forces it exhibits. Instructions

C2H6 - Only London dispersion forces CH3F - London dispersion and dipole-dipole interactions

Match each compound below with the intermolecular forces it is capable of exhibiting.

C3H8 - Only london dispersion CH3Cl- London dispersion and dipole-dipole interactions CH3OH - london dispersion, dipole-dipole interactions, and hydrogen bonding

Select all the compounds that have London dispersion forces.

CH4 NH3 H2O

Select all the compounds that have dipole-dipole interactions.

CHCl3 CH3OCH3 CH3F

Select all of the polar molecules from the formulas shown.

CHCl3 O=C=S SO2

Which atom has the smallest electronegativity?

Cs

What type of intermolecular force exists between the permanent dipoles of two polar molecules?

Dipole-dipole interactions

Which of the following are examples of consumer uses of hydrogen peroxide, H2O2? Select all that apply.

Disinfecting wounds Whitening teeth

Select the statements that correctly relate intermolecular forces to physical properties.

For compounds of similar size, the stronger the intermolecular forces, the higher the melting point. For compounds of similar size, the stronger the intermolecular forces, the higher the boiling point.

Which of the bonds listed below are polar? Select all that apply.

H-Cl C-F

Which of the following species have a trigonal planar geometry?

H2C=O, CO3 2-, & SO3

Which of the following molecules have a bent geometry?

H2S, SO2, & O3

Which of the following molecules have a linear geometry?

HCN & CO2

Select all the compounds that can participate in hydrogen bonding.

HF NH3 H2O

Select all the statements that correctly describe intermolecular hydrogen bonding.

Hydrogen bonding is an intermolecular force existing between two molecules that have hydrogens bonded to an O, N, or F.- Hydrogen bonding is important to many biological molecules including DNA- Hydrogen bonding occurs when a hydrogen atom is electrostatically attracted to an oxygen, nitrogen, or fluorine atom

Select the statement that best defines intermolecular forces.

Intermolecular forces are attractive forces that exist between molecules.

What type of intermolecular force is exhibited by all covalent compounds?

London dispersion

Select the statements that correctly describe London dispersion forces.

London dispersion forces result from the weak interactions between temporary dipoles. All covalent compounds exhibit London dispersion forces.

Which atoms have a higher electronegativity than arsenic (As)?

N & P

Which of the following molecules are polar? Select all that apply.

NH3 HCN FCH3

Which of the following molecules have tetrahedral shape?

NH4 + & CH2Cl2

Which atoms have a higher electronegativity than carbon?

O, N, & F

Hydrogen bonding occurs when a hydrogen is bonded to an electronegative atom. Select all the electronegative atoms that can participate in hydrogen bonding.

Oxygen, Fluorine, Nitrogen

Which of the following molecules have a trigonal pyramidal geometry?

PF3 & NH3

Select the statement that best describes the melting point of a compound.

The melting point is the temperature at which a solid is converted to a liquid.

Match the molecular geometry and the number of lone pairs of electrons on the central atom.

Trigonal planar geometry - 0 Trigonal pyramid geometry - Only 1 Bent geometry - 1 or 2

True or False: Polar bond and polar covalent bond are synonymous terms.

True

Electronegativity measures

an atom's attraction for electrons in a bond.

Dipole-dipole interactions are the attractive forces between the permanent __________ of polar molecules.

dipole

London dispersion forces are very weak interactions due to the momentary changes in __________ density in a molecule.

electron

The boiling point of a compound is the temperature at which a liquid is converted to the _________ phase.

gas

The _____ an atom's electronegativity, the _____ it "wants" shared electrons.

higher; more

What is the strongest type of intermolecular force?

hydrogen bonding

As covalent molecules increase in size, the dispersion forces ______.

increase

A mixture of dimethyl ether and propane is used in an over-the-counter device to treat warts, by freezing them. The structure of dimethyl ether is shown. Is dimethyl ether a polar or nonpolar molecule?

polar

Identify the geometry of the molecule in the image shown.

trigonal planar

Which molecular geometry is represented in the image shown?

trigonal pyramid

An atom with a bent shape is surrounded by _____ atoms and _____ lone pair(s) of electrons. (Select all that apply.)

two; two two; one

When can a molecule that contains polar bonds be nonpolar?

when individual bond dipoles cancel