Chapter 3: Matter and Energy

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Chapter 3 Matter and Energy
Chemistry 1020 Interpretive chemistry Andy
Aspaas, Instructor
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What are properties?

• Characteristics of a substance under observation
• Can be directly observable
• Indirectly observable observe the way it
  interacts with other substances

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Matter and energy

• Matter is the part of the universe that has mass
  and volume
• Energy is the part of the universe that has the
  ability to do work
• Chemistry is the study of matter
• Properties of matter
• Behavior of matter under influence of other
  matter and/or energy

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Properties of matter

• Physical properties characteristics that can be
  changed without changing the composition of the
  matter
• These are directly observable
• Chemical properties determine how the
  composition of matter changes when matter
  interacts with other matter or energy
• These describe the behavior of matter

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States of matter
State Shape Volume Compress Flow
Solid Keeps shape Keeps volume No No
Liquid Takes shape of container Keeps volume No Yes
Gas Takes shape of container Takes volume of container Yes Yes
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Changes in matter

• Physical changes change the form of a substance
  but not what its made of
• State changes
• Shape changes
• Dissolving
• Chemical changes the fundamental components of a
  substance are changed
• A new substance is formed
• Chemical reaction takes place

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Elements and compounds

• Element substance that cannot be broken down
  into other substances by chemical means
• Contains a single type of atom
• Ex. Aluminum contains only aluminum atoms
• Compound substance consisting of different
  elements chemically combined together
• Can be broken down into pure elements by chemical
  methods
• Ex. Water consists of H2O molecules, can be
  broken down into hydrogen and oxygen

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Mixtures and pure substances

• Mixture something with variable composition
• Coffee can be strong or weak
• Can be separated into 2 or more pure substances
• Pure substance always has the same composition
• Pure water always has the exact same composition

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Types of mixtures

• Homogeneous mixture the same throughout
• Also called a solution
• Ex. Air, saltwater, brass
• Heterogeneous mixture contains regions with
  different properties than others
• Ex. Sand in water, a casserole

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Separation of mixtures

• Distillation separation of a solution by boiling
  one compound away from the other
• Purification of seawater
• Filtration separation of heterogeneous mixtures
  by trapping solids in a filter
• Purification of sand in water

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Energy, temperature, and heat

• Energy is the capacity to do work
• Energy can change the temperature of substance
• Heat a flow of energy due to a temperature
  difference
• Heat is transferred from warm areas to cool areas
• Exothermic process heat is given off
• Endothermic process heat is absorbed

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Calculating energy changes

• Calorie amount of heat energy required to raise
  the temperature of 1 g water by 1 C
• Joule SI unit of heat
• 1 cal 4.184 J
• Specific heat capacity amount of energy required
  to raise the temperature of 1 g of any substance
  by 1C
• Water 4.184 J / g C
• Aluminum 0.89 J / g C
• Gold 0.13 J / g C

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Specific heat capacity calculations

• Q s x m x ?T
• Q heat energy required
• s specific heat capacity
• m mass of sample in grams
• ?T change of temperature required in C