CHEM II: Liquids Properties and Structure

What is surface tension?

The property of liquids that results from the tendency of liquids to minimize their surface area; layer of molecules on the surface behave differently than the interior

What factors affect surface tension?

• The stronger the intermolecular attractive forces, the higher the surface tension

• Raising the temperature of a liquid reduces its surface tension

What is viscosity?

the resistance of a liquid to flow; often given in centipoise

How do intermolecular attractions affect viscosity?

The larger the intermolecular attractions, the larger viscosity

How does temperature affect viscosity?

The higher temperature, the lower the viscosity

What is capillary action?

Capillary action is the ability of a liquid to flow up a thin tube against the influence of gravity

What forces work together to affect capillary action?

cohesive forces attract the molecules together, adhesive forces attract the molecules on the edge to tube’s surface

What is solid to liquid called?

fusion

What is liquid to solid?

freezing

What is liquid to gas?

vaporization

What is gas to liquid

condensation

What is solid to gas?

sublimation

What is gas to solid?

deposition

What is enthalpy of fusion?

The amount of energy required to overcome enough intermolecular forces to convert a solid into a liquid

What is enthalpy of vaporization

The amount of energy necessary to convert a liquid into a gas

Is enthalpy of vaporization exothermic or endothermic?

endothermic; therefore, positive

How are the heat of vaporization and condensation related mathematically?

-(change in heat of condensation) = +(change in heat of vaporization)

What is dynamic equilibrium?

when two opposite processes reach the condition so that there is no gain or loss of material

What is vapor pressure?

the pressure exerted by the vapor when it is in dynamic equilibrium with its liquid

What is normal boiling point?

the normal boiling point is the temperature at which vapor pressure of the liquid equals 1 atm

What is the clausius-clapeyron equation

can be used to predict the vapor pressure if you know the heat of vaporization and the normal boiling point
ln(P2/P2) = -(Heat of Va)/R((1/T2) - (1/T1))

What is a supercritical fluid?

contains properties of both gas and liquid states

What is the critical point?

temperature and pressure required to produce a supercritical fluid