Chapter 1 Chemistry: Matter and Measurement

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Chapter 1 Chemistry Matter and Measurement
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Chapter Outline

• Chemistry and the Elements
• Elements and the Periodic Table
• Measurement and Units
• Accuracy, Precision and Significant Figures
• Unit Conversion

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Classification of Matter

• What are the states of matter?
• Matter can be a gas, a liquid, or a solid.
• Gases have no fixed shape or volume and can be
  compressed to form liquids
• Liquids have no shape, but they do have a volume.
• Solids are rigid and have a definite shape and
  volume.
• This can be understood by taking a look at whats
  happening on the molecular level!

Phases Animation
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Classification of Matter

• Atoms
• Molecules
• One element (H2, O2, Cl2)
• More than one type of atom - a compound (H2O)
• Mixture - more than one type of atom, element, or
  compound are found together

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Elements

• Building blocks of matter
• There are 114 elements known.
• Each element is given a unique chemical symbol
  (one or two letters).
• The earths crust consists of 5 main elements
• The human body consists mostly of 3 main elements

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Many things in life occur over and over again in
a repetitive or periodic manner.
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Periodic Table

• Dmitri Mendeleev (1834-1907)
• arranged the known elements in order of
  increasing atomic weight beginning with hydrogen
• he observed that when elements are arranged in
  this manner, certain sets of properties recur
  periodically
• he then arranged elements with recurring sets of
  properties in the same column (vertical row) Li,
  Na, and K, for example, fall in the same column
  and start new periods (horizontal rows)

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Noble Gases
Alkali Metals
Alkaline Earths
Halogens
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Classification of Elements

• Metals
• are solids (except for Hg), shiny, conductors of
  electricity, ductile, and malleable
• form alloys (solutions of one metal dissolved in
  another) brass, for example, is an alloy of
  copper and zinc
• tend to give up electrons in their chemical
  reactions
• Nonmetals
• except for hydrogen (H), lie on the right side of
  the Periodic Table
• except for graphite, do not conduct electricity
• tend to accept electrons in their chemical
  reactions

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Classification of Elements

• Metalloids
• six elements are classified as metalloids boron,
  silicon, germanium, arsenic, antimony, and
  tellurium
• some of the properties of metals and some of
  nonmetals for example, they are shiny like
  metals but do not conduct electricity
• one of the metalloids, silicon, is a
  semiconductor it does not conduct electricity
  under certain applied voltages, but becomes a
  conductor at higher applied voltages

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Examples of Periodicity

• The halogens, Group 7A elements

Halogens An. (M)
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Chemical Properties

• Property a characteristic that can be used to
  describe or identify matter
• i.e. size, odor, color, melting point,
  solubility, etc
• Extensive Property do depend on amount of
  substance
• i.e. length, volume
• Intensive Property do not depend on the amount
  of substance
• i.e. melting point

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Chemical Property vs. Physical Property

• Chemical Property characteristics that do
  involve change in the chemical makeup of
  substance
• i.e. rusting
• Physical Property does not involve a change in
  chemical makeup of substance
• i.e. melting

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Activity Chemical Change

• Draw a representation (a picture) of how you
  think a chemical reaction works. Use the reaction
  between hydrogen and chlorine as an example.
• Your picture should show how you think the
  particles are arranged as reactants and how this
  arrangement changes in order to make the entirely
  new substance known as the product.
• Compare your picture with the picture of three of
  your classmates.

Sodium demo or anim
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Experimentation and Measurement

• Chemistry is an experimental science
• Must Measure!!
• SI International System of Units
• Based on metric system

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Units of Measurement
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Must quickly master the use of common metric
prefixes and scientific notation!
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Measuring Mass

• Mass amount of matter in an object
• Common units of mass
• Kilogram (kg)
• Gram (g)
• Milligram (mg)
• Microgram (ug)

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Measuring Length

• Meter standard unit of length
• Centimeter (cm)
• Millimeter (mm)
• Micrometer (um)
• Nanometer (nm)
• Picometer (pm)
• 1 x 10-12 m

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There are Three Temperature Scales

• Kelvin Scale
• Used in science.
• Same temperature increment as Celsius scale.
• Lowest temperature possible (absolute zero) is
  zero Kelvin.
• Absolute zero 0 K -273.15 oC.

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• Celsius Scale
• Also used in science.
• Water freezes at 0 oC and boils at 100 oC.
• To convert K oC 273.15.
• Fahrenheit Scale
• Not generally used in science.
• Water freezes at 32 oF and boils at 212 oF.
• To convert

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Volume

• Space occupied by solid, liquid or gas
• V (units of length)3
• Base unit Liter (L)
• 1 mL 1 cm3 1 cc

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Why do some things float and And some things
sink?
1kg of cotton balls 1kg of copper metal
Same mass, different?
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Density

• Example If 73.2 mL of a liquid has a mass of
  61.5 g, what is its density in g/mL?

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Is a solid more dense than liquid?
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Measuring Accuracy Precision
Accuracy how close to true value Precision
how well data points agree with one another
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The following table indicates the weight of a
tennis ball on three different instruments
What does the table indicate about Precision and
Accuracy? What does the table indicate about
choice of instrument?
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Uncertainty

• To indicate uncertainty in a measurement, the
  value you record should use all the digits you
  are sure of , plus on additional digit that you
  estimate!

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Lets Practice!!
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Significant Figures

• Handout
• Significant figure practice activity
• Practice, Practice, Practice!!!!

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Practice

• What are the number of significant figures in
  each of the following
• 1282 kg
• 0.00296 s
• 8.070 mm
• 0.0105 L
• 3000 yards

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More Practice

• Round each of the following to four significant
  figures and express in scientific notation
• 300.235900
• 0.006543210
• 456,500

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Unit Conversion

• Method of calculation utilizing a knowledge of
  units.
• Given units can be multiplied or divided to give
  the desired units.
• Conversion factors are used to manipulate units
• The conversion factors are simple ratios

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Unit Conversion

• Conversion factor
• a ratio, including units, used as a multiplier
  to change from one system or unit to another
• 1 lb 453.6 g
• Example convert 381 grams to pounds
• Example convert 1.844 gallons to milliliters

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Unit Conversion

• In dimensional analysis always ask three
  questions
• What data are we given?
• What quantity do we need?
• What conversion factors are available to take us
  from what we are given to what we need?

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Activity

• Perform the following conversions.
• 1. 0.290 g to mg
• 2. 1.5 km to mm
• 3. 2 qt to ml
• 4. 1500. cm to yards
• 5. -20.2 degrees F to K

Possibly useful 454 g 1.00 lb 946 ml 1.00
qt 2.54 cm 1.00 in
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