Chem 132 LearnSmart Ch. 12.3, 13.1-4

What principal intermolecular force keeps these molecules together? CH3OH CH3F C3H8 CaCl2

CH3OH-hydrogen bonding CH3F-dipole dipole C3H8-dispersion CaCl2-ionic bonding

What is van der Waals distance?

The shortest distance between two non-bonded atoms in adjacent molecules

Which of the following statements correctly describe bonding and intermolecular forces? Select all that apply. a) bonding forces are generally much stronger than intermolecular forces b) intermolecular forces involve partial or small charges that are far apart and are relatively weak c) for a molecular substance, the strength of the intermolecular forces determines the physical properties of its phases d) bonding forces occur within the nucleus of the atom and are therefore strong

a) bonding forces are generally much stronger than intermolecular forces b) intermolecular forces involve partial or small charges that are far apart and are relatively weak c) for a molecular substance, the strength of the intermolecular forces determines the physical properties of its phases

Which option correctly reflects the relationship between molecular shape and strength of dispersion forces? a) molecules with a large surface have more points of contact and therefore experience stronger dispersion forces b) molecules with a small surface are can pack more closely together and therefore experience stronger dispersion forces c) two molecules of the same molar mass will experience the same dispersion forces regardless of their shape

a) molecules with a large surface area have more points of contact and therefore experience stronger dispersion forces

Which of the following options correctly reflects the relationship between dispersion forces and particle size? Select all that apply. a)larger particle are more polarizable and experience stronger dispersion forces b) dispersion forces tend to decrease with size as larger particles are farther apart and therefore attract each other less c) dispersion forces are strongest for small particles since they can get closer together in space d) for molecules of similar shape, dispersion forces tend to increase with increasing molar mass

a)larger particle are more polarizable and experience stronger dispersion forces d) for molecules of similar shape, dispersion forces tend to increase with increasing molar mass

What term is used to describe the distance between the nuclei of two bonded atoms?

bond length

Which of the following statements correctly describes dispersion or London forces? Select all that apply. a) dispersion forces are stronger for smaller molecules b) dispersion forces are the primary intermolecular force exhibited by polar molecules c)all covalent compounds exhibit dispersion forces d) dispersion forces are a weak attraction between temporary dipoles

c) all covalent compounds exhibit dispersion forces d) dispersion forces are a weak attraction between temporary dipoles

What term is used to describe half the distance between the nuclei of two covalently bonded atoms?

covalent radius

Which intermolecular force occurs when two polar molecules orient themselves so that the positive end of one molecule attracts the negative end of the adjacent end of the other?

dipole dipole

Which intermolecular force do all particles experience?

dispersion

All particles experience __________ forces, a weak attraction that results from induced electron cloud distortion. These forces increase the overall attraction between particles. The more polarizable a particle is, the ________ this effect will be.

dispersion, stronger

What is covalent radius?

half the distance between the nuclei of two covalently bonded atoms

What is van der Waals radius?

half the shortest distance between the nuclei of two identical non bonded atoms

What is polarizability?

how well the electron cloud around an atom responds to change in its electronic environment

Are covalent bonds intermolecular or intramolecular forces?

intramolecular forces

Is a smaller atom or ion more or less polarizable than a larger one? Hint: think about the distance the electrons are to the nucleus and how tightly they are held of small atoms/ions versus larger ones

less polarizable

What term is used to describe how well the electron cloud around an atom responds to change in its electronic environment?

polarizability

With dispersion, if a particle is more polarizable, will the force be weaker or stronger?

stronger

What is bond length?

the distance between the nuclei of two bonded atoms

What term is used to describe the shortest distance between two non bonded atoms in adjacent molecules?

van der Waals distance

What term is used to describe half the shortest distance distance between the nuclei of two identical non bonded atoms?

van der Waals radius