Properties of Matter

1
Properties of Matter
Problem Set Reacting Quantities Masses
Are taste and smell intensive or extensive
properties?
Are mass, volume and density intensive or
extensive properties?
2
Chemical Stoichiometry

• Edward A. Mottel
• Department of Chemistry
• Rose-Hulman Institute of Technology

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Chemical Equations

• Stoichiometry (atom balance)
• Charge (charge balance)
• Format
• Phase annotation (s, l, g, aq)
• Arrow notations
• Reading assignment
• Zumdahl Chapter 2.1-2.4, 3.6-3.7

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Annotated (g, l, s, aq) Equations

• The phase of a reactant or product is often
  important.
• gas
• liquid
• solid
• aqueous solution

Write an annotated equation for the decomposition
of a 3 solution of hydrogen peroxide to
give water and oxygen.
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Things to Think About whenWriting a Chemical
Equation.

• What is the formula of the reactant product?
• What is the phase of the reactant product?
• Does it dissolve?
• What would you observe?
• How could you predict it?

Write an equation for what occurs when solid
sodium hydrogen carbonate is mixed with water.
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Solid Sodium Hydrogen Carbonate is Mixed with
Water
Does it ionize?
How could you tell?
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Sodium Hydrogen Carbonate

• Why is it called sodium bicarbonate?

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Nomenclature

• Give two acceptable names
• for each of these ions.

HSO4
HSO3
HS
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HCl(g) NaHCO3(aq)
NaCl(aq) CO2(g) H2O(l)

• Let
• be oxygen
• Ó be carbon
• Ä be hydrogen
• be sodium
• ? be chlorine
• Rewrite the equation in terms of graphics

How does your chemical equation
demonstrate Daltons atomic theory?
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Atomic TheoryJohn Dalton (1809)
In a chemical reaction, the way the atoms are
bound together changes, but the atoms dont
change.
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• Each elemental substance cannot be divided
  indefinitely, but is composed of fundamental
  subunits called atoms.

• Atoms of different elements have different
  properties
• mass, size, reactivity, etc.

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• In chemical reactions, atoms are never
  interconverted, created or destroyed.

• Each pure compound contains different elements
  which occur in a specific ratio with respect to
  one another.

• Chemical changes involve the rearrangement of
  atoms.

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19th Century Chemistry
3 grams of carbon
4 grams of oxygen
Analyzed reactions using weights and volumes
16
Amadeo Avogadro (1811)

• In a fixed volume, at a given temperature and
  pressure, every gas contains the same number of
  particles (molecules).

Avogadro never heard of the term mole, or
Avogadros Number!
Theory was not accepted for 50 years.
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Atoms are Small

• Generally measured in atomic mass units (amu) or
  daltons
• Carbon-12 (6 protons and 6 neutrons) has a mass
  of exactly 12.000 amu
• The conversion factor from an atomic quantity
  (amu) to a measurable quantity (gram) is the mole.

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A Mole is Big

• One mole equals 6.022 x 1023 units of anything.
• 6.022 x 1023 amu 1.000 mole of amu 1.000 gram

19
Limestone

• Limestone is a naturally occurring material
  consisting principally of calcium carbonate.
• Upon heating (roasting) at gt1000 C, it
  decomposes into calcium oxide (lime) and carbon
  dioxide.

You are the chief engineer. How could you
determine when this roasting process is completed?
20
Limestone

• If you began with 1000. grams of limestone, and
  the limestone was heated,
• what would be the percentage converted when the
  mass of solid is 900. grams?
• what would be the mass of solid when it is 95
  converted?

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Problem Set Reacting Quantities Masses
22
Hydrogen PeroxideDecomposition
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Team Peroxide

• With your team "diagram" your approach to solve
  the following problem.

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• Concentrated hydrogen peroxide contains 30
  hydrogen peroxide by weight and the balance
  water. The density of 30 hydrogen peroxide is
  1.110 gmL-1.
• Hydrogen peroxide decomposes upon standing, over
  a period of several months, to form water and
  oxygen.
• Assume an empty 500 mL plastic bottle used to
  hold hydrogen peroxide has a mass of 100.0 grams.

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• What would be the difference in mass and the
  percentage difference in mass between 500 mL of
  fresh 30 hydrogen peroxide in the 500 mL bottle
  and a bottle of hydrogen peroxide which is
  decomposed?
• Assume any oxygen gas formed escapes.
• The density of water at 25.0 C is 0.9970gcm-3.
• The density of pure hydrogen peroxide is 1.442
  gcm-3.

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