Unit 7: Lesson 2 Intermolecular Forces II

________ forces in a capillary action are intermolecular attractions between the liquid and the glass.

Adhesive

________ ___ _____________ is the heat absorbed when water is boiling

Enthalpy of vaporization, ΔH(vaporization)

In boiling, __________ occurs ___________ the liquid when the vapor pressure equals the atmospheric pressure. As a bubble forms, more water _______ into the bubble. The _______ pressure inside the bubble pushes boiling water to the side.

Evaporation inside evaporates vapor

What does Enthalpy of vaporization and Enthalpy of fusion look like on a temperature vs heat graph?

Flat lines

How to calculate sublimation enthalpy?

Sum of fusion enthalpy and vaporization enthalpy

Water rises up a capillary because _________ forces and _______ forces are at work.

adhesive cohesive

Surface tension The particles within a liquid experience forces or attraction in _______ directions. The particles on the surface of a liquid are attracted to particles _______ and ______ them. On a freshly waxed car, there is ________ ______ intermolecular attraction between the polar water molecules and the non-polar wax.

all beside underneath almost no

Temperature is the measure of the _________ ________ ________ of atoms and molecules in a system.

average kinetic energy

Grey area Dissolving a salt in water involves ________ ionic bonds and _________ ion-dipole interactions

breaking creating

Surface tension The particles within a liquid experience forces or attraction in all directions, so the force vectors ______, and there is ______ ______ attraction.

cancel no net

If a small-diameter glass tube (________) is placed in water, water ______ up the tube.

capillary rises

Chemical processes Involve the breaking and/or formation of ______ ______

chemical bonds

________ forces in a capillary action are intermolecular attractions between molecules in the liquid.

cohesive

Energy must be added to a liquid in order to __________ its surface tension and __________ its surface area. Surface tension _____ as temperature _________.

decrease increase decreases increases

When at a higher elevation, atmospheric pressure and boiling point ________ .

decreases

Viscosity __________ as the temperature increases. Particles at a higher temperature have more _______ to ________ the forces of attraction.

decreases KE counteract

Boiling point __________ as elevation increases, although boiling point changes food still needs to be cooked at a ___________ temperature.

decreases specific

Polar molecules in a solid state line up in a regular pattern to form strong __________-_________ attractions that maintain the ________ of the structure. _________ _________ forces also exist in solids.

dipole dipole organization London dispersion

Cooking is an ___________ chemical reaction.

endothermic

ΔH+ is

endothermic

The process is __________ as it gets closer to the _______ phase because it needs energy to break the intermolecular attractions.

endothermic gas

In a closed container, a liquid will reach a state of equilibrium where: rate of evaporation = rate of condensation. If you add heat, the equilibrium will shift in the _______________ direction to produce ________ gas.

endothermic more (products)

The heat required to liquify 1 mole of a substance is its _________ _________ _________ , _________. For water, this occurs at 0 degrees celsius.

enthalpy of fusion ΔH(fus)

Sublimation is when solids can ______ and have a _________.

evaporate vapor pressure

In a closed container, a liquid will reach a state of equilbrium where: rate of _____________ = rate of __________

evaporation condensation

ΔH- is

exothermic

The process is __________ as it gets closer to the _______ phase because it releases energy to form the intermolecular attractions.

exothermic solid

Plastics are generally __________ solids or __________ liquids. _______________ plastics increases flexibility, and allows them to be molded. Properties of synthetic materials can be __________ by manipulating their structure.

flexible viscous Heating modified

Physical processes involve changes in weak ______ ______

intermolecular interactions

Heat fusion is defined as the heat gained as 1 mol of solid _______.

liquefies

During supercooling the substance remains in the _______ phase after the temperature has dropped below the -________ temperature.

liquid freezing

The vapor pressures of ionic solids are very ________ because of the strong coulombic interactions between cations and anions.

low

Vapor pressures of solids are typically _________. If they have ______ vapor pressures, it's because they have relatively ______ intermolecular forces.

low high weak

Partial pressure of a certain gas is determined by the relative number (or ______ _______) of those particles that are present in a gaseous system...not the type of _______ __________.

mole fraction gas particle

A _________ __________ on surface molecules causes some to accelerate into the ______________ of the liquid.

net force center

In a gas, we generally assume that particles have _____ intermolecular forces of attraction. In a liquid, attractive forces are still quite _______.

no large

Enthalpy of vaporization and Enthalpy of fusion, energy is used to overcome intermolecular forces _____ _______ Kinetic energy.

not increase

Heat fusion is defined as the heat gained as 1 mol of solid liquefies. The energy released when 1 mol of a pure liquid solidifies is equal in magnitude but _________ in sign.

opposite

If a small-diameter glass tube (capillary) is placed in mercury, the _____ of water occurs. The adhesive forces between Hg and the glass are _______ than the cohesive forces between the Hg atoms.

opposite weaker

A system becomes more stable when its PE is _________. The ______ PE is achieved with the _________ possible surface area (a spherical shape).

reduced lowest smallest

In a solid, molecules are held close together in a ________ ______ by intermolecular forces.

regular pattern

Surface tension is the _________ of a liquid to spread out and ________ its surface area. Ex:

resistance increase Water beading on a freshly waxed car.

Viscosity is the measure of a liquid's _______ to flow. Viscosity increases as the strength of intermolecular forces _______.

resistance increases increases

As a general rule, the boiling point __________ as the amount of energy required to push liquids into the gas phase _______. This reflects the type of ___________ forces that the substance exhibits and its ______.

rises increases intermolecular size

As you continue to add heat to a solid that is liquefying, it stays at the ______ temperature until all of it has ________. The internal energy of the system is _____________, but the temperature is not, because the energy is being used to _________ the attractions from intermolecular forces.

same liquefied increasing sever/stretch

Surface tension A ___________ shape has the smallest surface area.

spherical

The vapor pressure on the surface of a liquid depends on the __________ of its _________ forces. A molecule restrained by strong intermolecular forces requires _________ energy to break free from its liquid state. When a system requires ________ energy to cause its molecules to enter the gas phase, it will also require _______ energy to cause its vapor pressure to equal the atmospheric pressure.

strength intermolecular more more more

In a liquid the intermolecular forces of attraction exist. These aren't as ________ as the intermolecular forces of solids.

strong

The Adhesive forces in a capillary action are _________ than the cohesive forces. The ______ forces pull the water up the walls of the glass tube, and the _________ forces pull up the liquid. Resulting in a small ________.

stronger adhesive cohesive meniscus

Liquids with __________ intermolecular attractions have larger differences in potential energy between interior and surface molecules, and ________ surface tensions.

stronger greater

As ionic bonds are much _______ than intermolecular forces, the ΔH(fus) values for ionic compounds are very _______. That's why ionic bonds have ________ melting points.

stronger large higher

The intermolecular forces in the liquid phase are much ________ than they are in the gas phase. Ideally, gas particles experience ______ intermolecular forces whatsoever and if they do, it's ___________.

stronger no negligable

Some liquids ________ before they solidify.

supercool

At the bottom of the ________ curve, _______ crystals form. This causes the temperature of the system to _______ dramatically, as heat is released by the solvent particles during the process of solidification.

supercooling solid increase

Evaporation is when liquid turns to gas at the ___________ of a liquid and when __________ the temperature of the boiling point.

surface below

Remember that ___________ is the only stress that changes the value of the equilibrium constant, K(eq).

temperature

Vaporization is when liquid turns to gas at certain _______ and _______.

temperature pressure

A liquid boils when its ______ pressure equals the _________ pressure.

vapor atmospheric

In a closed container, the __________ __________ is the partial pressure of the gas on the surface of its liquid when the system is at equilibrium.

vapor pressure

When a syst reaches its boiling point , it stays at the same temperature until all of the liquid has _____________. This heat is instead used to _____________ attractions from intermolecular forces.

vaporized severe

The bubbles in boiling water has _______________ _______________ not _______________ _______________.

water vapor air bubbles

Intermolecular forces of attraction are _______ in the liquid phase than they are in the solid phase. Energy must be _______ in order to reduce these restraints.

weaker absorbed