TAMINGTHE

TAKSTEST

OBJECTIVE FOUR

• Chemistry– Periodic Table (metals, nonmetals, noble

gases)– Atoms and bonding atoms– Properties of Matter– Physical vs Chemical Changes– pH levels– Everything to know about WATER and

SOLUTIONS

Color the Table like this pictureRed, Green, Blue are METALSYellow are NONMETALSOrange are NOBLE GASES

What are Groups & Periods?

Groups/Families• Vertical Columns

(Up & Down)• Elements share

SIMILAR PROPERTIES because they have the same # of valence electrons (outer energy level)

Periods• Horizontal Rows

(Side to Side)• Elements are very

DIFFERENT from each other

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

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.

Where are the metal elements?

Left of the Stair-step line!

Properties of Elements - Metals

• Metals are: –Conductors

–Lustrous

–Electron donors

–Malleable

–Ductile

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

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

Where are Noble Gases?Last column on the right! They are perfect!

Use the Table provided! What do the numbers mean?

Na

11

22.990

sodium

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.

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.

This is the name of the element.

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.

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.

What are Valence Electrons

• Every circle is an energy shell or orbit number

• Each shell holds a certain number of electrons

Shell # # of Electrons 1 2 2 8 3 18

MAGIC NUMBER TO REMEMBER IS 88 IS GREAT!

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 NO3

1-.• 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.

Vocabulary

• Compound - a pure substance composed of two or more elements whose composition is constant

• Mixture - an aggregate of two or more substances that are not chemically united and that exist in no fixed proportion to each other.

• Solution - such a substance, as dissolved sugar or salt in solution

• Alloy - a substance composed of two or more metals, or of a metal or metals with a nonmetal, intimately mixed, as by fusion or electrodeposition.

Law of Conservation of Mass

• Mass cannot be created or destroyed…its always there.– Ionic bonding– Covalent bonding

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)

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

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

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

• Group -ate becomes –ic and -ite becomes –ous.

• H2SO3 sulfurous acid

• H2SO4 sulfuric acid

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 tabletB The severity of the patients’ cold symptomsC The chemical formula for vitamin CD The amount of time before symptoms improve

What doesn’t 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 differencesC 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.

Matter• Anything

that has mass and takes up space.

• Energy is NOT matter

Matter is divided into 3 types:

• Elements

• Compounds

• Mixtures

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 in a few minutes.

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

The 3 types can be further separated in two categories:

• Pure Substances

• Elements are the simplest pure substances

• Mixtures are not pure substances. Each part of a mixture keeps its own properties, and can be separated out by a physical change.

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

P r o p e r t i e s o f M i x t u r e s :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.

There are two types of mixtures:

• Heterogeneous-Heterogeneous- mixture is not the mixture is not the same from place to same from place to place. place. – Chocolate chip Chocolate chip

cookie, gravel, soil. cookie, gravel, soil.

• Homogeneous-Homogeneous- same same composition throughout. composition throughout.

– Kool-aid, air, brass. Kool-aid, air, brass.

Decide if the substance is Element, Compound , or Mixture?

1. Water

2. Table Salt

3. Oxygen

4. Dirt

5. Air

1. Compound

2. Compound

3. Element

4. Mixture

5. Mixture/Solution

Click Mouse button to see answers!

6. Copper

7. Soda

8. Steel

9. Rain

10. Ice-cream

6. Element

7. Solution/Mixture

8. Solution/Mixture

9. Mixture

10. Mixture

Click Mouse button to see answers!

Let’s try a few more!

Other Properties of Matter

• Density – the amount of matter in a given volume (diet coke vs coke)

• Viscosity – resistance of fluid to flow (blood is thicker than water)

• Buoyancy – tendency of a less dense substance to float in a more dense liquid (diet coke vs coke)

If you’ve ever carried bags of groceries, you know that some bags have greater mass than others, even though the volumes of the bags are the same. Mass and volume are general properties of all matter. Density is the ratio of mass to volume. The density of a specific kind of matter helps to identify it and to distinguish it from other kinds of matter. The unit for density of a liquids is grams per milliliter (g/mL).

Density

• The density of a piece of matter is a combination of how compressed the material is and how much its atoms or molecules mass per unit volume. Water has a greater density than steam because the atoms in a liquid are closer together than those in a gas. But iron is denser than ice, because the iron atoms are heavier than the water molecules, even though they both are solids.

• Density is defined as the mass of a substance divided by its volume. The equation that is used for determining the density, D, of a substance is D = m/V, where m is the mass of the object, and V is its volume. More dense liquids will sink in the presence of less dense liquids.

• As temperature is increased (or decreased) there is no change in the mass of an object. However, since substances generally expand as they are heated, the volume will increase with an increase in temperature. This increase in temperature will cause the density to decrease.

Density same on the Moon

• Since density is related to the mass of an object, the density of a given volume of lead would be the same on both the Earth and the Moon, although the lead would weigh less on the Moon because of the lower gravity there.

• Typically, when you freeze a liquid, its atoms or molecules get closer together, such that the solid is more dense than the liquid. An exception to this is when you freeze water. When ice is formed, it actually expands, thus making it less dense than water. After the temperature drops below -3 degrees C, the ice contracts and becomes more dense.

Viscosity is a property that is often called on when liquids need to be classified. Each liquid has a different viscosity, or resistance to flow. Peanut butter has a much higher resistance to flow than milk, and thus it has a much higher viscosity than milk. We like ketchup that has a high viscosity. Likewise, motor oil is more viscous than gasoline.

Viscosity

The viscosity of motor oil is what allows the motor oil to stick to the metal parts of the engine. The weights given on motors oils ,S.A.E. values, correspond to "real" viscosity, taken at specific temperatures. Oils that fall into a certain range are designated 5, 10, 20, 30, 40, 50 by the S.A.E. The W means the oil is suitable for Winter use.

• Viscosity is a measure of the ease with which molecules move past one another.

• Viscosity depends on the attractive force between the molecules.

• Viscosity decreases with increasing temperature - the increasing kinetic energy overcomes the attractive forces and molecules can more easily move past each other.

Viscosity also affects the shapes of lava flows and the mountains they erupt from. The more viscous the magma, the fatter the lava flow. Also, the more viscous the magma erupted, the steeper the volcano.

The viscosity of a given liquid is due to:• the shapes of the molecules• the attractive forces present between the

molecules. • Substances with a high viscosity typically have

both of these characteristics. The polar ends of the molecules attract each other, while the long structures of the molecules "get tangled" with other molecules. A viscous liquid is somewhat like a tank of snakes with each snake biting another snake’s tail, and each snake’s body wrapped around another snake’s body.

You may have heard that 90% of an iceberg lies below the water. Why is that? What determines whether something sinks or floats, and, if it floats, how much of it remains above the surface?

Buoyancy!

Buoyancy is the tendency of an object to float in a fluid. It is controlled by

differences in density between the object and the fluid. Buoyancy is summed up by Archimedes Principle: Any object, wholly or partly immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

People or objects that float are positively buoyant. Things that are too heavy and sink, they are negatively buoyant. Neutral buoyancy occurs when the force of gravity is balanced by the buoyant force. Divers want neutral buoyancy, a scuba diver does not want to float to the surface or sink to the bottom.

Two important forces are in play when Surfing: Buoyancy and Gravity:The water exerts its force on every part of the board that it touches. The weight of the surfer and board give a downward force due to gravity.

Three cubes of equal size are put in a fish tank. The left cube is made of stone, the middle cube is made of a plastic with equal density as water, the right cube is made of wood

Force of Gravity

Buoyant force

Negatively buoyant

Positively buoyantNeutrally

buoyant

Whether an object floats or sinks, is based onnot only its weight, but also the amount ofwater it displaces. That is why a very heavyocean liner can float. It displaces a largeamount of water.

• When an object displaces a fluid it is basically pushing the fluid out of the way. Objects with a large volume displace more fluids that those with small volumes. The more fluid an object displaces the more buoyant that object will be.

A block of wood made of oak, for example, sits deeper in the water (and therefore displaces more of the water) than does a block of pine. The reason is that it's heavier for its size, or denser -- in this case, the molecules that make it up are more closely packed together than the molecules that make up the pine.

Density = Mass / Volume THIS IS FROM THE FORMULA PAGE25 A block of maple wood with a volume of405 cubic centimeters and a density of0.67 g/cm3 is sawed in half. The densityof the two smaller blocks is now —A one-fourth the original densityB one-half the original densityC two times the original densityD 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

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!

mL 78.0

x

Changes in Matter – Physical, Chemical or Nuclear?

• Physical changes do not change the substance.

• Everything with water (ice is still water)

• 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.

• Fire, listen, smell

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.

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)

Is this Physical or Chemical

http://www.epa.gov/ogwdw/kids/flash/flash_watercycle.html

Is this Physical or Chemical?

• Saliva breaks down the food turning it into chyme and works its way through the digestive system

Another technique for separating mixtures:

Evaporation: changing from

a liquid to vapor state– leaves behind the other

component.

Distillation:– Process used to

remove vapor from liquid by heating

– Great for separating two or more liquids which have different boiling points.

WATER! WATER! WATER!

• H2O = 2 hydrogens and 1 oxygen

• Water is POLAR due to uneven sharing of electrons

• The polarity makes water an effective solvent!

• Covalent bonding

O

H H

pH Scale

• pH scale ranges from 0 to 14 and measures the amount of H+ (hydrogen ions) and OH- (hydroxyl groups)

• Each number represents a factor of 10

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.

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.

SolutionsSolutions–S o l v e n t - the substance

doing the dissolving in a solution

–S o l u t e - the substance that is being dissolved in a solution

– Ex – Kool-aid• Water is the solvent • Sugar and powder is the solute

Solubility

• Greatest amount of solute that a solvent will dissolve before the solution becomes saturated

• Don’t understand …Then lets make some!

Factors that Influence Solubility

TemperatureMost solids increase solubility with increase in temperatureGas solubility decreases with increasing temperatures

PressureGas solubility always increases as pressure increasesScuba divers = water pressure increases as you descend

Surface AreaIncrease surface area to increase rate of dissolvingex – granular sugar dissolves quicker than sugar cubes

The three methods to increase the rate of solution

for a solid are?

•Heat it!

•Crush it! •Stir it!

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.

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

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

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?

F Decreasing the water temperature

G Stopping the stirring

H Lowering the air pressure

J Crushing the crystal

What are the 3 ways to increase the rate at

which a solid dissolves?

Heat it!

Crush it!

Stir it!

ANSWER?

J

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.

Gra

ms

solu

te/1

00 g

H2O

51 At which temperature do KBr and KNO3 have the same solubility?

A 27°C

B 48°C

C 65°C

D 80°C

Try this one!

49 According to the graph, about how muchhemoglobin would be saturated at an O2pressure of 7.3 kPa?A 32%B 67%C 89%D 92%

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.

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.

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

39 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 gSince 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.

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).

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.

K + H2O KOH + H2

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.

H OH 22 2

Balance the equation below, the boxes should get the coefficients.

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?

22

C

WE REALLY NEED TO DO SOME TAKS QUESTIONS

BECAUSE THE EXIT LEVEL TEST HAS MORE

CHEMISTRY AND PHYSICS ON IT!