Phase Change: solid to liquid Melting

water Most solids shrink in size when frozen. What substance is an exception and actually expands?

GAS Use the phase diagram below to answer the following question. Use the phase diagram below to answer the following question. What phase of matter would this substance be in at 90  C and 0.25atm? A B C

Heat energy is either absorbed or released What can cause a phase change of matter?

What phase of matter is “B”? A B C Temperature  Pressure  Liquid

________is the gas phase of a substance normally solid or liquid at room temperature Vapor

C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of C was decreased, the system would shift to the ________ C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of C was decreased, the system would shift to the ________ LEFT

Freezing occurs by the release of _____ energy

Describe a volatile liquid in terms of its rate of evaporation. Evaporates quickly

______ is the resistance of a liquid to flow Viscosity

What phase of matter is “A”? A B C Temperature  Pressure  Solid

A _____________ is a graph of pressure versus temperature that shows which phase a substance exists in under different conditions of temperature and pressure. Phase diagram

What is the normal boiling point of water? 100  C

Melting occurs by energy being ______. absorbed

Released Deposition occurs when energy is (absorbed OR released).

____________ is the temperature and pressure at which all 3 states of matter are at equilibrium Triple point

Phase Change: solid to gas Sublimation

The triple point of this substance occurs at: 5.2 atm & K

When a system at equilibrium is disturbed by application of a stress, it attains a new equilibrium position that minimizes the stress. This is known as ___________ Le Chatelier’s Principle

C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of CO was increased, the system would shift to the ________ C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of CO was increased, the system would shift to the ________ LEFT

_______ is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature. Equilibrium vapor pressure

________ is the temperature at which equilibrium vapor pressure equals atmospheric pressure Boiling point

__________ is a dynamic condition in which two opposing physical or chemical changes occur at equal rates in a given closed system Equilibrium

____________ is the spontaneous mixing of two or more substances. Diffusion

When does a liquid boil? Equilibrium vapor pressure EQUALS atmospheric pressure

What is the most abundant liquid? Water

_____________ is the energy required to increase the surface area of a liquid by a given amount; results from an uneven distribution of attractive forces. Surface tension

List 2 examples of surface tension. Meniscus Droplets can form Objects float Capillary rise

List a volatile substance Rubbing alcohol Nail polish remover Gasoline hairspray

When energy is taken away from a substance, the particles would move __________ Slower

Phase Change: liquid to solid Freezing

What happens to the boiling point of liquids on top of Mt. Everest? WHY? Boiling point is lower B/c atmospheric pressure is lower

C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of H 2 O was increased, the system would shift to the ________ C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of H 2 O was increased, the system would shift to the ________ Right

How does a substance evaporate, if equilibrium vapor pressure is LOW? WHY? SLOWLY! B/c there are STRONG IM forces and requires MORE kinetic energy to become a vapor

Describe a liquid in terms of particle spacing. Particles are packed relatively closely together

Describe a liquid in terms of particle motion. Particles vibrate around MOVING points

Water, olive Oil, Tree Sap Arrange the following in order of increasing viscosity at room temperature: tree sap, water, olive oil.

C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of H 2 was decreased, the system would shift to the ________ C(s) + H 2 O(g) CO(g) + H 2 (g) If the concentration of H 2 was decreased, the system would shift to the ________ RIGHT

Phase Change: gas to liquid Condensation

Describe the general volume of a liquid and use KMT to explain. Definite VOLUME- b/c particles are close together

Describe the general shape of a liquid and use KMT to explain. NO Definite SHAPE- b/c particles vibrate around moving points

Describe a liquid-vapor system at equilibrium. The number of particles vaporizing is EQUAL to the number of particles condensing

Unequal distribution of charge (oxygen is partially negative while hydrogen is partially positive) Why water is considered a polar molecule?

Phase Change: gas to solid Deposition

Both have particles changing from a liquid to a gas (vaporization) How are boiling and evaporation alike?

Phase Change: liquid to gas Vaporization

Temp. remains constant (does not change!) What happens to the temperature of substance during a phase change?

Phase change __________ is the transitioning from one state of matter to another.

Solid Use the phase diagram below to answer the following question. Use the phase diagram below to answer the following question. What phase of matter would this substance be in at 10  C and 1.0atm? A B C

Evaporation ONLY takes place at the surface and boiling vaporization is throughout liquid Heat is needed for boiling to occur and not for evaporation How are boiling and evaporation different? List one difference

RELEASED Condensation occurs when energy is (absorbed OR released).

What phase of matter is “C”? A B C Temperature  Pressure  Gas

What is the difference between the IM forces during melting and freezing? Melting = Less IM forces b/c more particle collisions Freezing = MORE IM forces b/c particles are moving slower

Using KMT, explain the evaporation rate of a volatile liquid. Quick evaporation rate. ◦ Has weak IM forces between particles so it requires LESS kinetic energy to become a vapor

Using KMT, explain the evaporation rate of a nonvolatile liquid. Slow evaporation rate ◦ Has strong IM forces between particles so it requires MORE kinetic energy to become a vapor

Rubbing Alcohol – it evaporates quickly b/c there is WEAK IM forces between the particles Which would you expect to be more volatile, water or rubbing alcohol? Explain.

 B/c of the hydrogen bonding- the arrangement of the molecules in the solid crystalline structure take up more space, yet have the same mass; making ice less dense than liquid water. Explain why the solid state of water (ice) is less dense than the liquid state.

When energy is added to a substance, the particles would move ___________ Faster

Energy exchanges are not changes in kinetic energy – so temperature remains constant. ◦ Heat energy is used to change the IM forces between the molecules Explain why the temperature remains constant during a phase change.

FALSE they are the same = 0°C TRUE or FALSE: The temperature at which a substance freezes is lower than the temperature at which it melts. Why?