Chemistry Review

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Chemistry Review

• Please have a sheet of Paper for
• Practice Questions during this
• Presentation

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Types of Measurement

• Qualitative measurement uses words to
• describe something. (i.e. A yellow-green
• gas was released.)
• Quantitative measurement uses numbers
• to describe something. (i.e. The oxide has
• a mass of 1.567 grams.)

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Temperature Scales

• Celsius, Kelvin, Fahrenheit
• Converting Celsius to Kelvin
• C 273 ____K
• a. Example 25 C ______
• 25 273 298 K
• Converting Kelvin to Celsius
• K - 273 ______C
• a. Example 300 K _________C
• 300 273 27 C

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Classification of Matter

• The law of conservation of matter states that
• matter can neither be created nor destroyed.
• Matter

anything that has mass and occupies space
Are the properties and composition constant?
yes
no
physical change
mixture
pure substance
seawater mud fruit salad
Is chemical separation into simpler
substances possible?
yes
no
chemical compound
element
water, sodium chloride
oxygen, gold, sulfur
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Classification of Matter

• Compound A substance with a constant
• composition that can be broken down into
• elements by chemical processes.
• Ex H2O (Water always has the same composition
  of Hydrogen (H) to Oxygen (O)
• 2 Hydrogen to every 1Oxygen
• Element A substance that cannot be
• decomposed into simpler substances by
• chemical means.
• Example Hydrogen, Oxygen, Carbon
• (Substances on the Periodic Table)

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Classification of Matter

• Mixture
• 1. Components of two or more components that
• can be separated by physical means, such
• as evaporation, filtration, or distillation
• 2. No chemical bonds between the separate
• parts
• 3. Components can vary in composition
• Example Salt Water the parts of salt and water
  can be separated by evaporating the water

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Classification of Matter

• Two kinds of mixtures
• 1. Homogeneous mixtures (solutions)
• A. can be solids, liquids, or gases
• B. are evenly mixed, appear as one
• component even though there are two or
• more parts.
• 1. Examples plain jello (solids)
• air (gases) and lemonade (liquids)

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Classification of Matter

• 2. Heterogeneous mixtures
• A. are unevenly mixed
• B. can see separate components
• C. Examples dirt, concrete, Oil and vinegar
  salad dressing

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Classification of Matter

• Classify these as an element, a compound, a
• heterogeneous mixture, or a homogeneous
• mixture.
• 1. concrete
• 2. air
• 3. salt
• 4. gold
• 5. helium
• 6. tea
• 7. salt water

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Answers

• 1. heterogenous Mixture
• 2. homogenous mixture
• 3. compound
• 4. element
• 5. element
• 6. homogenous mixture
• 7. homogenous mixture

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Metric Prefixes

• Metric Prefixes and Powers of 10
• 1. mega 106 (megagrams) (Mg)
• 2. kilo 103 (kilograms) (kg)
• 3. base 100 (grams) (g)
• 4. centi 10-2 (centigrams) (cg)
• 5. milli 10-3 (milligrams) (mg)
• 6. micro 10-6 (micrograms) (µg)
• 6000 mg _____ g _____ kg _____Mg

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Answers

• 6 g .006kg .000006 Mg

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Precision vs. Accuracy

• Precision refers to how close a series of
• measurements are to one another.
• 1. Replication of result / value
• Accuracy refers to how close a measured value
• is to an accepted value.
• 1. True or correct result / value

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Seven Base SI Units

• 1. Length meter (m)
  
• 2. Mass kilogram (kg)
• 3. Time second (s)
• 4. Temperature Kelvin (K)
• 5. Current Ampere (amp)
• 6. Amount mole (mol)
• 7. Luminousity candela (cd)

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Derived Units

• Derived Units are combinations of two or more
• units.
• 1. Examples speed mi/hr or ft/sec
• density mass/volume
• area (length) (width)

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Density

• Density is the mass of a substance per unit
• volume of the substance.
• 1. density mass/volume (g/ml or g/cm3)
• 2. Water (the standard for all density values)
  
• 1.0 g/ml
• 3. 1ml 1cm3
• 4. What is the volume of a 50 g metal block
• with a density of 5 g/cm3 ?
• 5. d m/V, m dV, V m/d

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Answer

• 10 cm3

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Periodic Table of the Elements
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Atomic Structure

• atomic number number of protons
• 1. also represents number of electrons in an
• atom
• mass number total number of protons and
• Neutrons
• Isotopes are atoms of the same element that
  have the same number of protons, but a different
  number of neutrons.

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The Chemists Shorthand Atomic Symbols
39
mass number
K
? element symbol
19
atomic number
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Atomic Information

• Take out a sheet of paper and write down the
  answers to these questions
• 1. What is the name of the isotope K-39?
• 2. How many protons are in K-39 ?
• 3. How many neutons are in this atom?
• 4. How many electrons are in this atom?
• 5. How many protons are in Potassium-40?
• 6. How many neutrons are Potassium-40?
• 7. What is the difference between K-39 and K-40?

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Atomic Information Answers

• 1. Potassium-39
• 2. 19, because the Atomic is 19
• 3. 20, 39-19 20
• 4. 19, electrons protons
• 5. 19, All Potassium atoms have 19 protons
  that is the atomic
• 6. 21 40-1921
• 7. K-39 has 20 neutrons and K-40 has 21 neutrons

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Periodic Table of the Elements
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Atomic Structure
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Atomic Structure
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Atomic Structure

• Particle Mass Charge
• Electron 9.11 x 10-31 - 1
• Proton 1.67 x 1027 1
• Neutron 1.67 x 1027 0

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Periodic Table of the Elements
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Periodic Table of the Elements

• Metals vs Nonmetals - see staircase on the
• Periodic table
• 1. Metals - to the left of the staircase mostly
  
• solids conduct electricity lose electrons
  to
• form positive ions
• 2. Nonmetals - to the right of the staircase
• most are gases nonconductors of
  electricity
• gain electrons to form negative ions
• 3. Metalloids - border the staircase have
• properties of metals and nonmetals.

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Periodic Table of the Elements
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Periodic Table of the Elements

• Groups
• 1. IA - Alkali Metals (1 valence electron) very
  reactive
• 2. IIA - Alkaline Earth Metals (2 valence
  electrons)
• 3. VIIA - Halogens (7 valence electrons) very
  reactive
• 4. VIIIA Noble Gases (8 valence electrons
  except for Helium) non-reactive (very stable)

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Atomic Structure

• In uncharged (neutral) atoms, the atomic
• number equals the number of protons equals
• the number of electrons.
• If an atom is charged (different number of
• protons and electrons), then it is called an ion.
• 1. A () charged ion is called a cation.
• 2. A (-) charged ion is called an anion.

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Periodic Table of the Elements

• Groups (vertical - up and down the table)
• 1A alkali metals forms 1 ions
• 2A alkaline earth metals forms 2 ions
• 7A halogens forms 1 ions
• 8A noble gases do not form ions (Why?)
• Periods (horizontal - across the table)
• numbered 1-7

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What Ions are Formed?

• 1. What type of ions are formed for
• Calcium b) Lithium c) Magnesium?
• d) These ions are called________________
• What type of ions are formed for
• Fluorine b) Oxygen c) Nitrogen?
• d) These ions are called________________

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Answers

• 1.
• Ca2 b) Li c) Mg2
• d) CATIONS (All Positive Ions-Metals)
• 2.
• a) F- b) O2- c) N3-
• d) ANIONS (All Negative Ions-Nonmetals)

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Periodic Table of the Elements

• There are 7 periods on the periodic table
• numbered 1 - 7.
• 1. They represent the major energy levels (n).
• 2. They are horizontal rows that extend from
• left to right.
• Ex Period 2 includes Li - Ne.

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Periodic Table of the Elements
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Periodic Table of the Elements

• Representative Elements - The Group A Elements
  which include all the Groups IA to VIIIA
• Transition Elements - The Group B Elements

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Periodic Table of the Elements
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Periodic Table of the Elements

• Lanthanide Series - the 4f row that includes
• 57 (Lanthanum) through 71 Lu
• Actinide Series - the 5f row that includes 89
• Ac (Actinum) through 102 No

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Periodic Table of the Elements
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Periodic Table of the Elements

• Atomic Radius - the distance from the center of
• the nucleus to the outermost valence shell
• Periodic Trend - The atomic radius increases as
• one moves down the group. The atomic radius
• decreases as one moves across a period.

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END of Module I