1. which type of intermolecular attractive force operates between all molecules?

a. dipole-dipole forces
b. ion-dipole forces
c. london dispersion forces
d. hydrogen-bonding forces

2. which type of intermolecular attractive force operates only between polar molecules?

a. dipole-dipole forces
b. ion-dipole forces
c. london dispersion forces
d. hydrogen-bonding forces
3. which type of intermolecular attractive force operates only between the hydrogen atom of a polar bond and a nearby small electronegative atom?

a. dipole-dipole forces
b. ion-dipole forces
c. london dispersion forces
d. hydrogen-bonding forces

1) C

2)A

3)D

Explanation:

London forces are common to all molecules, it results from momentary shifts in electron distribution in molecules. When molecules possess a permanent dipole, dipole-dipole interaction is the dominant intermolecular force. However, for compounds in which hydrogen is bonded to highly electronegative element, hydrogen bonding is important.

1↔C  2↔A  3↔D

Explanation:

London dispersion forces are weak Vanderwal forces that exists between

all molecules.

Dipole-dipole forces operates between polar molecules because of the attraction between slightly developed opposite charges.

Hydrogen-bonding is the strongest dipole-dipole interaction because of the largest electronegativity difference between hydrogen atom and the most electronegative atoms like F,O,N.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.