Liquids:

1
Liquids
Theyre Wet

• By Colleen Roe, Brendan McNulty, Danielle
  Pascetta, Nick Mingone, Nick Heine

2

• Liquids are everywhere in life. They are in
  us, around us, even in the atmosphere!

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The Nature of Liquids
4
The Nature of Liquids

• Liquids have a definite volume and indefinite
  shape
• Liquid particles are constantly in motion and
  free to slide past each other
• Like gases, liquids can flow but the particles
  are attracted to each other unlike gasses
• Attractive forces are called intermolecular
  forces

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The Nature of Liquids

• The motion of liquids contribute to the kinetic
  energy of the particles
• Even with all the kinetic energy, the liquids
  dont have enough kinetic energy to escape to the
  gaseous state
• Kinetic energy overcomes the intermolecular
  forces, allowing particles to flow

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The Nature of Liquids

• When liquids flow, there is an internal
  resistance to do this. This is called viscosity.
• Viscosity is a trait of all liquids and it has
  been found that the viscosity of liquids normally
  decreases as temperature increases.
• If the flow of liquids is smooth, it can be
  described quantitatively as laminar.

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The Nature of Liquids

• Laminar flow is when a series of thin plates of
  liquid slide past each other smoothly at
  different velocities.
• If the flow of liquid is non-laminar it is
  considered to have a turbulent flow.
• An example of a turbulent flow is when there is a
  mountain stream bubbling over rocks.

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The Nature of Liquids

• The most common device used to measure viscosity
  is the vertical Ostwald-type viscometer.
• Viscosity of a liquid is determined by measuring
  the rolling ball time between a fixed distance.

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The Nature of Liquids

• Liquids are much more dense than gases
• More dense because of intermolecular forces
• Intermolecular forces pull all the particles
  closer together, reducing space

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The Nature of Liquids

• Increasing the pressure on a liquid has little
  effect on its volume
• The same goes for solids-liquids and solids known
  as condensed states of matter
• Physical properties are determined by the
  disruptive motions of the particles

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Evaporation
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Evaporation

• Evaporation is a form of vaporization
• Vaporization is the conversion of a liquid to a
  gas or vapor
• When vaporization occurs at the surface of a
  liquid that is not boiling, it is called
  evaporation

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Evaporation

• Evaporation occurs when molecules break away from
  the liquid and enter the gas or vapor state

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Evaporation

• Liquids evaporate faster when heated
• This is because heat increases the kinetic energy
  of the liquids particles
• The kinetic energy enables the particles to break
  free from the liquid state

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Evaporation

• Evaporation is a cooling process
• It is a cooling process because the particles
  with high kinetic energy escape first
• This leaves the particles with lower kinetic
  energy in the liquid, therefore decreasing the
  temperature

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Evaporation
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Vapor Pressure
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Vapor Pressure

• Definition A force due to the gas above a
  liquid
• Occurs during the evaporation of a liquid in a
  closed container

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Vapor Pressure
Rate of evaporation of liquid Rate of
condensation of a vapor
A
C
B
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Vapor Pressure
Vapor Pressure is measured by a device called a
manometer.
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And now, lets get those pencils ready because
LIVE from the second floor presentation room, its
time for everybodys favorite part of the
presentation.
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TRUE or FALSE

• Liquids have a definite volume and an indefinite
  shape.
• Liquid particles are only in motion when they are
  hot.
• Intermolecular forces are the attractive forces
  between liquid particles.
• Viscosity is an external resistance
• Kinetic energy is what allows liquid particles to
  flow

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• Turbulent flow is when thin plates slide past
  each other smoothly.
• Viscometers are used to measure the viscosity of
  liquids.
• Gases are much more dense that liquids.
• Vapor pressure occurs during the evaporation of a
  liquid in a closed container.
• Increasing the pressure on a liquid has a very
  large effect on its volume.

24
Acknowledgments

• We would like to thank Grace Burn for figuring
  out how to get a video to move when we copied it
  into our presentation. Way to have our backs,
  Grace!

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References

• Textbook pgs. 274-277
• http//www.liquidsculpture.com/
• http//www.anton-paar.com/ap/apinternet/html/defau
  lt/cxsn-5qskkz.en.0.jsp?gclidCJ2uhfzcmIoCFQK3Sgod
  dHzcjA
• http//www.intute.ac.uk/sciences/reference/plambec
  k/chem2/p02306.htm