TAKS OBJECTIVE 4

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TAKS OBJECTIVE 4

• Matter and Change
• Obj 4.1 Complete the next 4 questions to see if
  you are in need of this tutorial.

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1. The picture shows a model of the element
A fluorine B helium C beryllium D oxygen
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Write down your answers, then check them. . .

• 2 Oxygen (O2) is an example of
• A an alloy
• B a molecule
• C a salt
• D a mixture

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USE THE FORMULA PAGE!

• 3. What is the density at 20C of 12.0
  milliliters of a liquid that has a mass of 4.05
  grams?
• A 0.338 g/mL
• B 2.96 g/mL
• C 16.1 g/mL
• D 48.6 g/mL

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5. According to the law of conservation of mass,
how much zinc was present in the zinc carbonate?

• A 40 g B 88 g C 104 g D 256 g

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Check your answers, if you get them all correct,
take the quiz at the end to be sure you can skip
this tutorial. . .

• C
• B
• A
• C

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Matter

• Anything that has mass and takes up space.
• Energy is NOT matter

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Matter is divided into 3 types

• Elements
• Compounds
• Mixtures

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The 3 types can be further separated in two
categories

• Pure Substances
• Elements are the simplest pure substances

• Mixtures are not pure substances and we will deal
  with them during 4.2

• Compounds which are formed when two or more
  elements share electrons or become ions that
  attract other elements.

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ElementsSIMPLIST KIND OF MATTER

• Cannot be broken down into simpler substances.
• All atoms of an element have the same number of
  protons.
• There are 109 of these currently listed and named
  on the Periodic Table

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4 Basic Types of Elements

• Metals found on the left and center of the Table
  of Elements
• Non-metals found on the right side of the Table
  of Elements
• Metalloids found along the stair-step line
• Synthetic made in the laboratory and not yet
  found in nature many of the Actinide and
  Lanthanide series and very large elements.

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The BOHR Model of an Atom

• This is the first model to have a nucleus with
  protons and neutrons.
• The electrons are in various energy levels and
  circle the nucleus.
• Model most people draw today.

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Drawing a Bohr Model of Lithium

• Center (blue) circle is the nucleus.
• It should contain 3 and 4N to represent the 3
  protons and 4 neutrons.
• The orange circle gets 2e-, and the purple gets
  1e-.

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Remember question 1?
How can you tell which element is represented?

• Count the number of protons.
• Protons are positive and found in the nucleus.
  
• There are 4, so this is the 4th element on the
  Periodic Table Be
• Answer C

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Atoms are. . .

• The smallest part of a single element.
• The basis of all matter. Word was first used by
  Democritus.
• Made of mostly empty space, and have a positive
  core or nucleus. (Rutherford)
• Have electrons in orbit in energy levels.
  (Dalton)

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What about MOLECULES?

• These are
• MULTI-ATOM particles

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Properties of Elements - Metals

• Metals are
• Conductors
• Lustrous
• Electron donors
• Malleable
• Ductile

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Where are the metal elements?
Left of the Stair-step line!
Most reactive
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Properties of Nonmetals

• Nonmetals are brittle, insulators, electron
  acceptors
• Usually form negative ions (except H)
• Many are gases at room temperature
• Found to the right of the stair-step line

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Where are the nonmetals?
Right of the stair-step line!
Most reactive
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Diatomic Elements Nonmetals that come as
molecules

• 7 Elements are di- (2) atomic (atoms)
• The easy way to remember them is by the name
• Br I N Cl H O F

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Example question

• 2 Oxygen (O2) is an example of
• A an alloy
• B a molecule
• C a salt
• D a mixture

Alloy is a mixture of metals NOPE!
A salt is a product of an acid base NOPE!
Mixtures contain more than one substance NOPE!
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T y p e s o f m a t t e r

• C o m p o u n d s -
• Pure substances that can be broken down by a
  chemical change.
• Molecules are the smallest particle of a compound
  that retains its properties and it is composed of
  2 or more atoms.

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Compounds
Pure substances that can be broken down by
chemical methods

• When they are broken down, the pieces have
  completely different properties than the
  compound.
• Made of two or more elements that are bonded by
  electrical charge or shared electrons.

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Names of Compounds Ionic

• Ionic compounds consist of cations (positive
  ions) and anions (negative ions).
• A Roman numeral in parentheses, preceded by the
  name of the element, is used for elements that
  can form more than one positive ion. This is
  usually seen with metals.
• Fe2 Iron (II) Cu Copper
  (I)Fe3 Iron (III) Cu2 Copper
  (II)

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Ionic compounds naming cont.

• The -ide ending is added to the name of a single
  element when it becomes an ion of that element.
  Oxide, Nitride, Sulfide etc.
• Some polyatomic anions have a names ending in
  -ite for the lower of oxygens and ate for
  more oxygens.
• NO2 nitrite NO3 nitrate

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Learning the TAKS Polyatomic Ions

• P-O-4 is phosphate, P-O-3 phosphite,
• S-O-4 is sulfate, and S-O-3 sulfite.
• C-O-3 is carbonate, N-O-3 is nitrate,
• N-O-2 is nitrite, and N-H-4 ammonium,
• O-H hydroxide, yes, O-H hydroxide.

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Covalent Compounds Names are the Formulas

• These are nonmetal to nonmetal compounds.
• The name tells you the formula.
• Carbon dioxide
• 1 C and 2 O
• CO2

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Special Names of Compounds Acids and Bases

• Bases end in the hydroxide anion OH-
• They are named with the metal and hydroxide.
• NaOH is sodium hydroxide

• Acids that are two elements are named
  Hydro-nonmetal ic Acid such as
• HCl hydrochloric acid
• If is has a group -ate becomes ic and -ite
  becomes ous.
• H2SO3 sulfurous acid
• H2SO4 sulfuric acid

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Which elements form covalent bonds?
The closer together the two elements are, and the
closer they are to Carbon, Group 14, the more
covalent the bonds become.
The closer the two elements are to the ends of
the table, Group I and Group 17, the more ionic
the compound.
Elements being arranged by similar chemical and
physical properties is credited to Dimitri
Mendeleev
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Changes in Matter Physical or Chemical?

• Physical changes are changes in the state of
  matter. They do not change the substance.
  (Melting, boiling, condensing, freezing, cutting)
  
• Chemical changes are reactions that result in new
  products with new properties.

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USE THE FORMULA PAGE!

• 3. What is the density at 20C of 12.0
  milliliters of a liquid that has a mass of 4.05
  grams?
• A 0.338 g/mL
• B 2.96 g/mL
• C 16.1 g/mL
• D 48.6 g/mL

Density Mass/ Volume that would be grams/mL or
4.05/12.0 0.338 g/mL
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Chemical Reactions

• Since matter can not be created or destroyed,
  chemical reactions must balance in terms of mass.
  
• The amount of mass you start with must be equal
  to the mass of the products.
• This is the LAW OF CONSERVATION OF MASS

• Reactants ? Products
• 100g total 100g total

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4. According to the law of conservation of mass,
how much zinc was present in the zinc carbonate?
Since matter can not be created or destroyed in
chemical reactions, the mass on both sides of the
arrow must be equal. So 64g 192g 256g and
152 g Zinc 256g There must be 104g of Zinc.
Answer C.

• A 40 g B 88 g C 104 g D 256 g

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Chemical Equations

• Whole numbers written in front of formulas are
  called coefficients. For example, 4 C6H12O6
  indicates that there are 4 molecules of glucose
  sugar.
• To determine how many total atoms of each element
  are present, multiply the coefficients by the
  subscripts for each element.
• 4 C6H12O6 would contain 24 atoms of carbon
• (4 x 6), 48 atoms of hydrogen (4 x 12), and 24
  atoms of oxygen (4 x 6).

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To balance equations

• The number of atoms of each type of element on
  the reactant side (left of the arrow) must be
  equal those on the product side (right side of
  the arrow).
• 2 H2 O2 2 H2O
• There are 4 hydrogen atoms on the left (2 H2) and
  4 hydrogen atoms on the right (2 H2O)
• There are 2 atoms of oxygen (O2) on the left and
  2 atoms of oxygen on the right (2 H2O). When a
  subscript is missing, it is understood to be 1.

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Balance the equation below, the boxes should get
the coefficients.
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Balance the equation below, the boxes should get
the coefficients.
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Which element does not have the same number of
atoms on both sides? Oxygen. It has 2 on the
reactant side and 3 on the product side. If we
put a coefficient of 2 in front of PbO, we will
now have 4 O and 2 Pb on the right. By placing
a coefficient of 2 in front of the reactant, we
have 2 Pb and 2 x 2 O. That means it is
balanced! Answer?
C
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Its now your turn.

• For each question, answer on your own paper under
  the title Objective 4.1
• When you have finished, please put your name and
  your science teachers name on it and turn it in.
  
• Have questions? Come see a science teacher, or
  attend other tutorials.

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• 1. Which of the following elements is the
  least reactive?
• At
• F
• Kr
• Li

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2. To produce 4 molecules of sugar, a plant
needs- A 6 molecules of hydrogen B 12 molecules
of ATP C 18 molecules of water D 24 molecules of
carbon dioxide
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• 3. Which of the sets of numbers correctly
  balances the chemical equation shown?
• ___ C2H6 ___O2 ? __ CO2 __H2O
• 1, 3, 2, 3
• 1, 1, 2, 3
• 2, 7, 4, 6
• 1, 3, 1, 3

TAKS 4 TEKS IPC 8C
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• 4. Which of the following is a compound?
• A. Cu
• B. O2
• C. H2O
• D. Mg

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• 5. Which of the following scientists
  contributed to chemistry by organizing the
  elements into the periodic table?
• Marie Curie
• Albert Einstein
• Dmitri Mendeleev
• J.J. Thomson

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6.
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Check your answers, if you missed any, please
attend the Objective 4 tutorials.

• C
• D
• C
• C
• C
• A

• The rest of Objective 4 and other objective
  reviews continues with 4.2.