Lab 1

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Lab 1 Introduction to biological sciences

• No quiz or worksheet due today

2
Outline of todays lab

• Atoms
• What are they made of?
• What makes different atoms different?
• How are ions and anions formed?
• pH
• What is it?
• What is the pH of various solutions?
• What are buffers?
• Using the metric system
• Practicing measurements / unit conversions.

3
Atoms!

• Composed of protons, neutrons, and electrons
• Protons 1 charge
• Electrons -1 charge
• Neutrons neutral
• Bohr Model is the classic model
• Protons and neutrons in the nucleus
• Electrons in shells around the nucleus

Bohr model of Boron
Periodic table ccasa by Armtuk http//commons.wiki
media.org/wiki/ImagePeriodic_Table_Armtuk3.svg
Boron art by Marc Perkins
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How do we figure out whats in each atom?
B
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Boron

• Protons
• protons Atomic number
• Neutrons
• neutrons Atomic mass - protons
• Unless its an isotope
• Electrons
• electrons protons
• Unless its an ion

10.81
5
Ions gaining or losing electrons

• Salt
• NaCl
• Sodium Chloride
• Na and Cl become ions
• Na loses an electron
• Cl gains an electron
• Written as
• Na
• Cl-

Chlorine atom (Cl)
Sodium atom (Na)
Chlorine atom (Cl-)
Sodium atom (Na)
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The periodic table
Periodic table ccasa by Armtuk http//commons.wiki
media.org/wiki/ImagePeriodic_Table_Armtuk3.svg
Boron art by Marc Perkins
7
Outline of todays lab

• Atoms
• What are they made of?
• What makes different atoms different?
• How are ions and anions formed?
• pH
• What is it?
• What is the pH of various solutions?
• What are buffers?
• Using the metric system
• Practicing measurements / unit conversions

8
Acidity

• Completely dependent on the concentration of
  protons (H) in solution
• The more protons (H), the more acidic
• The more things that absorb protons (e.g., OH-),
  the more basic

pH Scale ccasa by Slower http//commons.wikimedia
.org/wiki/ImagePH_scale.png
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Acid
Base
(hydrochloric acid)
(sodium hydroxide / lye)
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pHs of common items
pH Scale ccasa by Slower http//commons.wikimedia
.org/wiki/ImagePH_scale.png
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Buffers

• Chemicals that maintain a constant pH in a
  solution, even when acid or base is added
• Example Bicarbonate (NaHCO3)
• In solution dissociates into Na and (HCO3)-

Bicarbonate absorbs the proton!
Bicarbonate produces a proton! (that will react
with OH- to form H2O)
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Outline of todays lab

• Atoms
• What are they made of?
• What makes different atoms different?
• How are ions and anions formed?
• pH
• What is it?
• What is the pH of various solutions?
• What are buffers?
• Using the metric system
• Practicing measurements / unit conversions

13
Measuring volume

• Use the pipettes, graduated cylinders, or the
  scale
• 1 ml H2O 1g

Read the volume at the bottom of the meniscus
Meniscus diagram gnu FDL by Jleedev
http//en.wikipedia.org/wiki/ImageReading_the_men
iscus.png
14
The periodic table
Periodic table ccasa by Armtuk http//commons.wiki
media.org/wiki/ImagePeriodic_Table_Armtuk3.svg
Boron art by Marc Perkins
15
Before you leave

• Clean up your work area
• Wash glassware and store upside down
• Show me your lab report so I can stamp it
• Need to have all data fields filled in
• Complete at home and then turn in at the
  beginning of next lab
• Remember that well have a quiz at the beginning
  of the next class
• 6-7 questions on todays lab
• 3-4 questions on the lab well do next week

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Notes for the instructor

• If you need a screen-displayable periodic table
  that shows atomic masses, try this one by the
  IUPAC
• http//www.iupac.org/reports/periodic_table/

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License information

• This work is licensed under the Creative Commons
  Attribution-NonCommercial-ShareAlike 3.0 License.
  To view a copy of this license, visit
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• The slides in this presentation were originally
  created by Marc C. Perkins (http//faculty.orangec
  oastcollege.edu/mperkins).
• You are free to use, modify, and distribute these
  slides according to the terms of the Creative
  Commons license (e.g., you must attribute the
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• Attribution should be given to Marc C. Perkins
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  Marcs current website. This applies both while
  distributing the slides and during use of the
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  by, for instance, placing small text on at least
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  for an example).

Slides in this presentation based on those
created by Marc C. Perkins. http//faculty.orangec
oastcollege.edu/mperkins
18
History

• August 2007 Marc Perkins released first version.
  http//faculty.orangecoastcollege.edu/mperkins

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