intermolecular
forces are attractive forces between molecules
intramolecular
forces hold atoms together in a molecule
weaker
generally, are intermolecular forces stronger or weaker than intramolecular forces?
-water and its phases
-enzymes
-DNA
where can intermolecular forces be found / what makes intermolecular forces important
-dispersion forces (london forces)
-dipole-dipole interactions
-ion-dipole interaction
-hydrogen bonding
what are the four types of intermolecular forces?
dispersion forces (london forces)
weakest force, occurs in every compound, arise from the net attractive forces amount molecules which is produced from induced charge imbalances, exist between temporary dipoles
dipole-dipole interaction
occurs in polar molecules
ion-dipole interaction
occurs when an ion is attracted to a polar bond
hydrogen bonding
special type of dipole-dipole force that involves hydrogen with oxygen, nitrogen, or fluorine
how easily it is to distort the electron cloud
what is the magnitude of the dispersion force dependent on?
greater
the larger the molecule the _______________ its dispersion forces are
carbon; stronger; higher
more __________ = _____________ dispersion forces = __________ boiling point
polarizability
the ease which the electron distribution in the atom or molecule can be distorted
-greater number of electrons
-more diffuse electron cloud
what does polarizability increase with?
stronger
the larger the charge in a ion-dipole force, the _____________ the force
helps solid ionic crystal dissolve in water
what does ion-dipole interactions help with?
oxygen, fluorine, nitrogen
what are the only elements hydrogen can bond with in order to make a hydorgen bond?
because oxygen, nitrogen, and fluorine are the most electronegative atoms
why can hydrogen bonds only from between hydrogen and either oxygen, nitrogen, or fluroine?
cohesion
an intermolecular force, the force of attraction between identical molecules
adhesion
force of attraction between molecules and their container (meniscus)
surface tension
strong intermolecular forces = high _____________________
because the dipoles are permanent
why are dipole-dipole forces stronger than dispersion forces for molecules with comparable mass?
the strength attractive forces within and between particles
explain what determines a substance's state at a given temperature
the stronger the intermolecular attractive forces, the higher the viscosity
explain how hydrogen bonds affect the viscosity of a liquid
viscosity decreases with temperature
how does a change in temperature affect viscosity?
viscosity
resistance to flow
soap decreases the surface tension of water by disrupting the hydrogen bonds between the water molecules, when the hydrogen bonds are broken the water spreads out allowing the dirt to be carried away by the water
what effect does soap have on the surface tension of water?
because the adhesion forces between water molecules and the silicon dioxide in glass are greater than the cohesive forces between water molecules
explain why water forms a meniscus in a graduated cylinder
-high melting point
-high boiling point
-hard
-brittle
-poor conductor of electricity in solid state
-good conductor of electricity in liquid state or dissolved in water
ionic properties
-low melting point
-low boiling point
-exist as gases or vaporize easily (volatile)
-many are relatively soft solids
-relatively weak
-poor conductor of electricity
covalent properties
the hydrogen bonds in water held the water molecules together
what kept the water from flowing onto the table when it was 'hanging' over the edges of the penny?
hydrogen bonds
what type of intermolecular force occured in the water molecule?
dipole-dipole forces
what type of intermolecular force occured in the iso alchol molecule?