Chapter 2 Energy and Matter

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Chapter 2 Energy and Matter

• Energy is the capacity to do work.
• Work is the capacity to move an object over a
  distance against a resisting force.
• Three categories of energy
• Kinetic applies to objects in motion
• Potential energy that applies to an objects
  position, ex. Gravitational, electrical,
  chemical.
• Radiant Light energy

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Measurement

• Units Calorie, joule
• Calorie (cal) the amount of heat needed to raise
  1 g of water by 1 OC. This is known as the
  specific heat of water.
• Calorie (Cal) in food the Cal is equal to 1000
  cal or 1kcal.
• Joule Named for James Joule, 4.184 J 1 cal.
  The joule is an SI unit.
• 4.184 J will raise 1 g of water by 1OC.

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Conservation of Energy

• Measurement of energy transfer.
• Potential ? Radiant ? Kinetic no energy is lost
  or gained.
• What is the primary source of our energy?

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Temperature

• Galileo Galilei (1564-1642) invented the first
  thermometer.
• Gabriel Fahrenheit (1686-1736) thermometer maker,
  designed his own scale.
• Anders Celsius (1701-1744) designed around water.
  0 OC freezing, 100 OC boiling.
• William Thomson, Lord Kelvin (1824-1907)
• Absolute scale, absolute zero 0K or -273.15 OC.
• 1 OC ? 1K ?

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Temperature

• Centigrade ? Fahrenheit
• 1.8 x OC 32 OF
• Centigrade ? Kelvin
• OC 273.15 K
• Fahrenheit ? Centigrade
• ???
• Which scale is the SI unit?

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Matter

• Definition anything that has mass and volume.
  Examples?
• What cannot be classified as matter?
• States
• Solid high density, fixed shape and volume.
• Liquid high density, fixed volume, indefinite
  shape.
• Gas low density, indefinite shape and volume.
• Plasma low density, indefinite shape and volume.
  Exists at very high temps.

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Phase Change Diagram
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Properties and Changes of Matter

• Physical properties characteristics that are
  observed w/o changing the substance. Ex. Density,
  color, melting/boiling points.
• Chemical properties characteristics that are
  observed by altering a substance. Reactivity is
  the primary example.
• Like energy, matter is neither created nor
  destroyed. Law of Conservation of Matter

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Elements and Compounds

• Element any substance that cannot be separated
  into simpler substances by a chemical change.
• Compound a substance that contains two or more
  elements combined in a fixed proportion.
• Elements and compounds are pure substances.

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Mixtures

• A blend of two or more substances.
• Homogeneous vs. Heterogeneous
• Methods of separating mixtures filtration,
  chromatography, distillation (evaporation),
  crystallization.