General and Inorganic Chemistry

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General and Inorganic Chemistry

• Introduction to Chemistry

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What is Chemistry

• Chemistry is the study of chemicals how
  properties depend on composition. What substances
  are and how they change.
• El Khemid - the transformation. Chemistry is
  about changing substances into others.
• What chemicals? First metals then cosmetics,
  medicines, ceramics, glass making.

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What did early chemists do?

• Identify, classify, describe Knowledge leads to
  curiosity.
• Rather than learn all substances seek underlying
  patterns and theories that explain chemical
  behavior.
• Apply scientific method.

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Apply scientific method.

• Observation vs interpretation
• Observation - with statement of certainty is a
  fact
• Laws - generalized observations
• Hypothesis to explain observations - predictions
• Experiment - Test hypothesis
• Theory - tested hypothesis
• Model- Combination of theories that form a
  general explanation of wide variety of phenomenon

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A Delicate Balance

• Science is different from art in that scientific
  knowledge requires agreement first of the facts
  and then of the theories.
• There is a delicate balance between what is known
  and what we think about what is known.
• This is the idea of provisional truth we believe
  our hypotheses but maintain a healthy skepticism.

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Serendipity

• "Chance favors the prepared mind
• When asked what did you think when you saw the
  bones of your hand on the screen in front of the
  cathode ray tube? Roentgen replied I did not
  think. I investigated.

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How do we describe matter?

• Matter occupies space and has weight. (Actually
  Mass, weight is the affect of gravity on mass).
• Matter exists in three physical states.
• Solid
• Liquid
• Gas

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Properties of Matter

• Physical properties Color, mp, bp, density,
  index of refraction. Observation of these do not
  change chemical composition.
• Chemical properties Observation of these causes
  a chemical change substances become other
  substances. Reactivity with acids to liberate
  carbons dioxide.

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Physical properties

• Physical properties can be
• Extensive i.e. depend on amount of substance like
  mass or volume
• Intensive i.e. independent of amount like
  temperature or pressure.
• Some properties are qualitative others are
  quantitative.

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Quantitative properties.

• Measurements require a system of units
• SI- Systeme International
• Base units m, kg, s, K, mol
• Derived units Joule, liter, pascal
• Prefixes mega, kilo, deci, centi, milli, micro,
  nano, pico

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conversions
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Energy

• Energy ability to do work
• Kinetic mv2/2
• Potential - chemical
• Conservation of energy. Heat and work transfer
  energy

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Temperature zeroeth law

• Heat is the flow of energy from a hot object to a
  cold object.
• Heat flows from regions of high temperature to
  regions of low temperature.
• Differentiate between heat which is energy flow
  and temperature which gives the direction of flow.

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Accuracy and Precision

• An Advil Ô Tablet was "weighed" on a digital
  laboratory balance 22 times with the following
  results

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The normal distribution
mean 0.4586
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mean 0.4586
?, Standard deviation
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The normal distribution
67
95
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Significant Figures
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Every sample of a pure substance has the same
properties. In contrast the properties of
mixtures depend on the compostion of each sample
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Mixtures can be separated into their pure
components

• Mixtures can be separated into their pure
  components by physical means
• Filtration
• Mechanical separation
• Distilation
• Dissolving
• Chromatography

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Elements Compounds

• Elements can not be broken down into simpler
  substances
• Compounds can be chemically broken down into the
  elements of which they are composed.
• There are 108 elements known but 40 of these
  compose 99.9 of all substances.
• 10 elements compose 99 of the earths crust.

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Ten elements compose 99 of the earths crust
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Water
Earth
Fire
Air
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Three quarters of the elements are metals

• Metals are
• Malleable
• Ductile
• Lustrous
• Conductors
• heat
• electricity

The chemical symbols for some metals are not the
same as the first letter of the English name for
the element Pb-lead W-tungsten K-potassium Cu-cop
per Fe-iron Hg-mercury Na-sodium Sn-tin
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These non-metals are solids at room
temperature Arsenic-As Phosphorous-P
Sulfur-S Iodine-I Boron-B Selenium-Se
Carbon-C The rest are gases
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The Law of Constant Composition
The relative amounts of each element in a
compound are always the same.
Mass percentage or percent composition
Mass of Element
X 100
Mass of compound
Fe 1.56 g S 0.9007g 2.47g
massFe 1.56/2.47 x100 63.5