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Class TAKS Review Objective 4

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Soda 8. Steel 9. Rain 10. Ice-cream 6. Element 7. Solution/Mixture 8. Solution/Mixture 9. ... Slide 43 So, what is a suspension or colloid? Solutions: ... – PowerPoint PPT presentation

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Title: Class TAKS Review Objective 4


1
Class TAKS Review Objective 4
  • Matter and Change

2
Matter
  • Anything that has mass and takes up space.
  • Energy is NOT matter

3
Matter is divided into 3 types
  • Elements
  • Compounds
  • Mixtures

4
The 3 types can be further separated in two
categories
  • Mixtures are not pure substances and we will deal
    with them in a few minutes.
  • Pure Substances
  • Elements are the simplest pure substances
  • Compounds which are formed when two or more
    elements share electrons or become ions that
    attract other elements.

5
Atoms are. . .
  • The smallest part of a single element.
  • The basis of all matter.
  • Made of mostly empty space.
  • Have a positive core or nucleus.
  • Have electrons in orbit in clouds.

6
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.

7
Where are the metal elements?
Left of the Stair-step line!
8
Properties of Elements - Metals
  • Metals are
  • Conductors
  • Lustrous
  • Electron donors
  • Malleable
  • Ductile

9
Where are the nonmetals?
To the Right of the stair step line, and
Hydrogen!
10
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

11
23 According to the periodic table, which element
most readily accepts electrons?
  • A Fluorine
  • B Nitrogen
  • This is a nonmetal, so it accepts electrons but
    it will also share them as in NO31-.
  • C Arsenic
  • This is a metalloid, so it only sometimes accepts
    electrons.
  • D Aluminum
  • This is a metal so it donates electrons.

Fluorine only needs 1 electron to complete its
shell of 8, so it will accept it from any other
element very very very easily. This periodic
property increases as you move up and left in the
table, except for the Noble Gases.
12
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.

13
Use the Table provided! What do the numbers mean?
This is the atomic number. It is the number of
protons in a single atom of this element. By the
way, its also of electrons.
11
Na
The symbol for this element.
This is the atomic mass, it is the number of
protons neutrons, or the mass of the nucleus of
an atom.
22.990 sodium
This is the name of the element.
14
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

15
3 Which of the following groups contains members
with similar chemical reactivity?
  • A Li, Be, C
  • B Be, Mg, Sr
  • C Sc, Y, Zr
  • D C, N, O

16
Lets look at the Table provided.
  • To have similar chemical properties of any kind,
    they must be in the same Group or Family.
  • Groups are columns, so the answer would be
  • B

17
Chemical Reactivity
  • Metals increase in reactivity left and down.
  • Nonmetals become more reactive up and to the
    right.
  • Most reactive metal is?
  • Most reactive nonmetal is?

Fr
F
18
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)

19
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

20
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

21
Special Names of Compounds Acids and Bases
  • Acids that are two elements are named
    Hydro-nonmetal ic Acid such as
  • HCl hydrochloric acid
  • Group -ate becomes ic and -ite becomes ous.
  • H2SO3 sulfurous acid
  • H2SO4 sulfuric acid
  • Bases end in the hydroxide anion OH-
  • They are named with the metal and hydroxide.
  • NaOH is sodium hydroxide

22
15 An advertisement claims that patients can be
cured of the common cold in 48 hours by vitamin C
tablets with secret mineral supplements. In a
scientific experiment to test these claims, which
data can be considered irrelevant? A The amount
of vitamin C in each tablet B The severity of the
patients cold symptoms C The chemical formula
for vitamin C D The amount of time before
symptoms improve
23
What doesnt matter to the test?
  • A The amount of vitamin C in each tablet
  • This should be a controlled variable!
  • B The severity of the patients cold symptoms
  • This would be very hard to control, but a large
    experimental group should allow for differences
  • C The chemical formula for vitamin C
  • Compound formulas NEVER change so this is our
    answer it is irrelevant!!!
  • D The amount of time before symptoms improve
  • This is what we are testing, it is most relevant.

24
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.

25
Changes in Matter Physical, Chemical or
Nuclear?
  • Physical changes do not change the substance.
    The state of the matter may change, but it keeps
    its own properties.
  • Cutting a piece of wood does not change the wood,
    it is simply smaller.
  • Chemical changes are also called chemical
    reactions.
  • When a different substance is produced than what
    was present at the start, a chemical change has
    occurred.

26
Nuclear Changes Fission and Fusion
  • Fusion occurs when the nucleus of one atom is
    joined by the nucleus of another.
  • This is the reaction that occurs on the sun and
    stars.
  • It produces extreme energy release.
  • Fission occurs when the nucleus of an atom ejects
    particles and energy when hit by a subatomic
    particle such as a neutron.
  • This also causes a release of extreme energy and
    is the basis of atomic energy plants and bombs.

27
Density Mass / Volume THIS IS FROM THE FORMULA
PAGE
  • 25 A block of maple wood with a volume of
  • 405 cubic centimeters and a density of
  • 0.67 g/cm3 is sawed in half. The density
  • of the two smaller blocks is now
  • A one-fourth the original density
  • B one-half the original density
  • C two times the original density
  • D the same as the original density

If the block is cut in half, you cut the mass in
half AND you cut the volume in half, so Mass/2
or Volume/2 Mass x 2
(which is really 1) so . . . . Volume 2
28
20 A sample of an element has a volume of 78.0 mL
and a density of 1.85 g/mL. What is the mass in
grams of the sample? Record and bubble in your
answer to the nearest tenth on the answer
document.
Use the formula page, D M/V
1.85 g/mL
Multiply both sides by 78.0 mL and you get
144.3 g Grid it in!
29
Law of Conservation of Matter
  • Matter can not be created or destroyed.
  • The total mass of the substances before they are
    mixed is equal to the total mass as a mixture.

30
Chemical Reactions
  • Since matter can not be created or destroyed,
    chemical reactions must be balanced in terms of
    mass.
  • The amount of mass you start with must be equal
    to the mass of the products.
  • Reactants ? Products
  • 100g total 100g total

31
39 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

32
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).

33
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.

34
K H2O ? KOH H2
2
H OH
2
2
  • 19 What is the coefficient for H2O when the above
    equation is balanced?
  • A 1
  • B 2
  • C 3
  • D 4

To balance this equation, make water HOH, then
you will see that you need 2 H and get 2 OH
groups. That means the KOH gets a coefficient
of 2, the K gets a coefficient of 2 and The
water must also get a coefficient of 2.
35
Balance the equation below, the boxes should get
the coefficients.
2
2
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
36
The 3 types can be further separated in two
categories
  • Mixtures are not pure substances. Each part of a
    mixture keeps its own properties, and can be
    separated out by a physical change.
  • Pure Substances
  • Elements are the simplest pure substances
  • Compounds which are formed when two or more
    elements share electrons or become ions that
    attract other elements.

37
Decide if the substance is Element, Compound ,
or Mixture?
1. Water
1. Compound
2. Compound
2. Table Salt
3. Element
3. Oxygen
4. Mixture
4. Dirt
5. Mixture/Solution
5. Air
Click Mouse button to see answers!
38
Lets try a few more!
6. Copper
6. Element
7. Solution/Mixture
7. Soda
8. Solution/Mixture
8. Steel
9. Mixture
9. Rain
10. Mixture
10. Ice-cream
Click Mouse button to see answers!
39
P r o p e r t i e s o f M i x t u r e s
  • E a c h s u b s t a n c e r e t a i n s
    i t s o w n p r o p e r t i e s .
  • S u b s t a n c e s c a n b e
    p r e s e n t i n a n y a m o u n t .
  • S u b s t a n c e s c a n b e
    s e p a r a t e d b y s i m p l e
    p h y s i c a l m e a n s.

40
There are two types of mixtures
  • Heterogeneous- mixture is not the same from place
    to place.
  • Chocolate chip cookie, gravel, soil.
  • Homogeneous- same composition throughout.
  • Kool-aid, air, brass.

41
Separating Mixtures Physical Changes
  • Separation of mixtures could be
  • Magnetic removal (if there is Fe, Ni, Co)
  • Filtration (if there are large particles)
  • Hand sorting particles
  • Decanting (pouring off the less dense liquid)

42
Another technique for separating mixtures
  • Evaporation changing from a liquid to vapor
    state leaves behind the other component.

43
  • Distillation
  • Process used to remove vapor from liquid by
    heating
  • Great for separating two or more liquids which
    have different boiling points.

44
So, what is a suspension or colloid?
  • Colloids have small particles that are not
    visible by just looking. An example would be
    coffee.
  • However, they show the Tyndall Effect (see the
    laser light line).
  • They can not be separated by filtering.
  • Suspensions have larger particles, often visible
    in size.
  • The particles can be filtered out.
  • It scatters light No Tyndall Effect.
  • If left undisturbed, the particles will settle
    to the bottom.

45
Solutions 2 parts
  • S o l v e n t - t h e m o s t
    a b u n d a n t s u b s t a n c e
    i n t h e s o l u t i o n .
  • S o l u t e - t h e l e a s t
    a b u n d a n t s u b s t a n c e
    i n t h e s o l u t i o
    n .
  • Homogeneous You can not see any particles of
    either part!

46
The three methods to increase the rate of
solution for a solid are?
  • Heat it!
  • Crush it!
  • Stir it!

47
17 All of these can affect the rate at which a
solid dissolves in water except
  • A decreasing air pressure
  • B stirring the water
  • C increasing the temperature of the water
  • D using larger crystals of the solid

48
The three methods to increase the rate of
solution for a solid are?
  • Heat it! C
  • Crush it! D slows it
  • Stir it! B
  • So this eliminates choices B, C D
  • Which will NOT change it?
  • A
  • Answer choices were
  • A decreasing air pressure
  • B stirring the water
  • C increasing the temperature of the water
  • D using larger crystals of the solid

49
Solubility Factors What will dissolve?
  • Solubility Rules
  • 1. All sodium, potassium, and ammonium salts are
    soluble.
  • 2. All silver, lead, and mercury salts are
    insoluble.
  • 3. All carbonates, sulfides, and hydroxides are
    insoluble.
  • 4. All nitrates and sulfates are soluble except
    calcium sulfate and barium sulfate.

50
10 A 0.2 g crystal of gypsum dissolves very
slowly in 100 mL of water while the water is
stirred. Which of these would cause the gypsum to
dissolve faster?
  • What are the 3 ways to increase the rate at which
    a solid dissolves?
  • Heat it!
  • Crush it!
  • Stir it!
  • ANSWER?
  • J
  • F Decreasing the water temperature
  • G Stopping the stirring
  • H Lowering the air pressure
  • J Crushing the crystal

51
How much solute will dissolve?
  • A solubility curve shows the amount of each
    solute that will dissolve in 100g H20 at each
    temperature.
  • Saturated is on the line.
  • Unsaturated is below the line.
  • Supersaturated is above the line.

Grams solute/100 g H2O
52
  • 51 At which temperature do KBr and KNO3 have the
    same solubility?
  • A 27C
  • B 48C
  • C 65C
  • D 80C

53
Try this one!
49 According to the graph, about how
much hemoglobin would be saturated at an
O2 pressure of 7.3 kPa? A 32 B 67 C 89 D 92
54
Concentrated or Dilute?
  • A concentrated solution has as little solvent as
    possible.
  • A dilute solution has added solvent.
  • After adding more solvent, there is still the
    same mass of solute that you started with.

55
pH is a measure of the Strength of Acids Bases
  • Acids have 0-6.99 pH
  • Bases have 7.01-14 pH
  • Remember because A begins the alphabet and zero
    begins numbers
  • Litmus turns red in acids and blue in bases
  • Phenothalein turns pink in a base and stays clear
    in acids.

56
Higher pH levels means?
  • 33 Two clear solutions are placed in separate
  • beakers. The first solution has a pH of 4, and
    the pH of the second solution is unknown. If
  • the two solutions are mixed and the resulting
  • pH is 5, the second solution must have
  • A fewer suspended solids
  • B a lower temperature
  • C more dissolved salt (NaCl) particles
  • D a higher concentration of OH ions

Solutions are homogeneous and have no suspended
solids.
Nothing is mentioned about temperature so B is
invalid.
NaCl solutions are neutral so have no effect on
pH.
57
Now its your turn!
  • See if you can complete the questions provided.
    Be sure to ask a science teacher before next
    Friday, if there is a question you do not know.
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