Making Solutions of Differing Molarity Concentrations

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Making Solutions of Differing Molarity
Concentrations

• Lab Manual 3G

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timeline

• ThursdayLecture
• Monday-magic mountain
• Tuesdayquiz, Perform Lab
• ThursdayTurn in Lab

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Write-up

• Procedures (include TLABT 3 in procedures)
• Data --look at my table example to combine the
  tables to save work--record molecular weight for
  CuSO4
• Data Analysis and Conclusion (1-2 paragraphs)
• Thinking Like a Biotechnician (1-4)--3 must be
  done in the lab using the spect., 4 can be done
  on notebook paper

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Safety Precautions

• wear gloves and googles

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Prep. for lab 3g

• Check for cupric sulfate 5-hydrate, glass tubes
• Set-up spect.

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Lab 3G tips

• Do calculations in advanceshow how units cancel
• When making a solution, the solute is measured
  out first, and the solvent is mixed into the
  solute
• The mass takes up space, solutions are always
  prepared by raising the solvent to the final
  volume

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Formula for conversions

• Volume (L) x concentration (mol/L) x molecular
  weight (g/mol) ___g

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Background

• Periodic table for molecular weight
• Molarityexpresses concentration
• Moles/Liter
• We use lower M solutions (1M or lower)
• Make sure your total volume is in Liters for
  conversions!

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Molarity A brief history explanation

• What is an atom?
• How much do atoms weigh?

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Hmmm I propose that there should be something
called the atom.

• In 530 BC, Democritus came up with the idea of
  the atom.

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Several years later

1. Every element is made up of atoms.
2. All atoms of any element are the same.
3. Atoms of different elements are different.

• In 1808, John Dalton came up with the atomic
  theory

1. Atoms of different elements can combine to form
   compounds.
2. Atoms are not made destroyed or changed.
3. In any compound, the numbers and kinds of atoms
   remain the same.

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I may not be a looker, but I am very smart!
One liter of Nitrogen will always form with three
liters of Hydrogen to form Ammonia (NH3)
One liter of Hydrogen will always combine with
one liter of Chlorine to make Hydrogen Chloride
(HCl)

• Amadeo Avagadro was working with gases and
  discovered that when temperature and pressure are
  the same, gases combine in definite volume ratios.

So, he used this principle to get relative
weights from atom to atom.
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6.02 X 1023

• Do you have to know this?