Class TAKS Review Class TAKS Review Objective 4Objective 4

Matter and Change Matter and Change

MatterMatter

Phases of MatterPhases of Matter

SolidSolidLiquidLiquidGasGasPlasmaPlasma

Energy is lost or gained during phase Energy is lost or gained during phase changes!changes!

Kinetic Theory of MatterKinetic Theory of Matter

Matter is made up of particles which are in Matter is made up of particles which are in continual random motion.continual random motion.

SOLIDSSOLIDS

• Particles of solids are tightly packed, and vibrate in a fixed position.

• Solids have:

•a definite shape

•a definite volume

• Crystals are repeating geometric patterns of particles

Heat

LIQUIDSLIQUIDS Particles of liquids are Particles of liquids are

tightly packed, but are tightly packed, but are far enough apart to slide far enough apart to slide over one another. over one another.

Liquids have:Liquids have: an an indefiniteindefinite shape, and shape, and a a definitedefinite volume. volume. Heat

GASGAS Particles of gases are Particles of gases are

very far apart and very far apart and move freely. move freely.

Gases have:Gases have: anan indefinite indefinite shape shape an an indefiniteindefinite volume. volume. Heat

But what happens if you raise the But what happens if you raise the temperature to super-high levels…temperature to super-high levels…

between between 10001000°C and 1,000,000,000°C ?°C and 1,000,000,000°C ?

Will everything Will everything just be a gas?just be a gas?

STATES OF MATTERSTATES OF MATTERPLASMAPLASMA

A plasma is an ionized A plasma is an ionized gas.gas.

A plasma is a very good A plasma is a very good conductor of electricity conductor of electricity and is affected by and is affected by magnetic fields.magnetic fields.

Plasmas, like gases Plasmas, like gases have an have an indefiniteindefinite shape and an shape and an indefiniteindefinite volume.volume.

• Plasma is the most common state of matter in the universe

Some places where plasmas are Some places where plasmas are found…found…

1. Flames1. Flames

2. Lightning2. Lightning

3. Aurora (Northern 3. Aurora (Northern Lights)Lights)

4. The Sun is an example of a star 4. The Sun is an example of a star in its plasma statein its plasma state

PHASES (STATES) OF MATTERPHASES (STATES) OF MATTER

SOLID LIQUID GAS PLASMA

Tightly packed, in a regular pattern

Vibrate, but do not move from place

to place

Close together with no regular arrangement.Vibrate, move

about, and slide past each other

Well separated with no regular arrangement.

Vibrate and move freely at high

speeds

Has no definite volume or shape and is composed

of electrical charged particles

PHASE CHANGESPHASE CHANGESDescription of Phase Change

Term for Phase ChangeHeat Movement During

Phase Change

Solid to liquid

MeltingHeat goes into the solid as it melts.

Liquid to solid

FreezingHeat leaves the liquid as it freezes.

PHASE CHANGESPHASE CHANGESDescription of Phase

ChangeTerm for Phase Change

Heat Movement During Phase Change

Liquid to gasVaporization, (boiling and evaporation)

Heat goes into the liquid as it vaporizes.

Gas to liquid CondensationHeat leaves the gas as it condenses.

Solid to gas SublimationHeat goes into the solid as it sublimates.

How is water different from most other How is water different from most other substances when it changes from a substances when it changes from a

liquid to a solid?liquid to a solid? Water expands when freezing. Most Water expands when freezing. Most

other substances contract when other substances contract when freezing.freezing.

Water is most dense at 4Water is most dense at 4ooC C Ice floats because water in the solid Ice floats because water in the solid

phase is less dense than water in the phase is less dense than water in the liquid phase.liquid phase.

Unique characteristics of water are Unique characteristics of water are important for life on earth.important for life on earth.

Phase Change GraphPhase Change Graph Describe what happens at each section. Describe what happens at each section.

A: Ice meltingA: Ice meltingsolid solid → liquid→ liquid

B: Water is increasing B: Water is increasing in temperaturein temperature

C: Water is BoilingC: Water is Boilingliquid liquid → gas→ gas

At flat areas: energy At flat areas: energy used to overcome used to overcome bonding to complete bonding to complete phase changephase change

Matter Matter can be sub-divided can be sub-divided

into 3 types:into 3 types:Elements Elements CompoundsCompoundsMixturesMixtures

Cannot be broken down into Cannot be broken down into simpler substances.simpler substances.

All atoms of an element have All atoms of an element have the same number of protons. the same number of protons.

There are 109 of these There are 109 of these currently listed and named on currently listed and named on the Periodic Tablethe Periodic Table

Elements: SIMPLEST KIND OF MATTER

Atoms. . . Atoms. . . Are the smallest part of a Are the smallest part of a

single element. single element. Are the basis of all matter. Are the basis of all matter. Consist mostly of empty Consist mostly of empty

space. space. Have a positive core or Have a positive core or

nucleus. nucleus. Have electrons located in Have electrons located in

energy levels around the energy levels around the nucleus.nucleus.

Drawing a Model of Drawing a Model of Lithium-7Lithium-7

Atomic #-3Atomic #-3

Mass #-7Mass #-7

3+ and 4N represent the 3+ and 4N represent the 3 protons and 4 3 protons and 4 neutrons.neutrons.

Electron configurationElectron configuration1s1s222s2s11

PhosphorusPhosphorus Atomic numberAtomic number

1515 Mass numberMass number

3131 Number of protonsNumber of protons

1515 Number of neutronsNumber of neutrons

1616 Number of electronsNumber of electrons

1515 Electron configurationElectron configuration

1s1s222s2s222p2p663s3s223p3p33

Valence Electrons-Bonding Valence Electrons-Bonding ElectronsElectrons

Groups-vertical columns, valence electrons can be determined from the group numbers.

Periods-horizontal rows

Why is Group 18 non-reactive??Why is Group 18 non-reactive??

When the outer shell (s and p orbitals) of When the outer shell (s and p orbitals) of most atoms consists of 8 electrons, the most atoms consists of 8 electrons, the atoms no longer gain, lose, or share atoms no longer gain, lose, or share electrons.electrons.

Group 18 elements are called the Noble Group 18 elements are called the Noble Gases (described an inert).Gases (described an inert).

FluorineFluorine

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

(electronegativity) increases as you move up and left in the table, except for the Noble Gases.

General GuidelinesGeneral Guidelines

Metals tend to lose electrons Metals tend to lose electrons and become positive ions and become positive ions (Groups 1, 2, & 13)(Groups 1, 2, & 13)

Nonmetals tend to gain Nonmetals tend to gain electrons and become electrons and become negative ions (Groups 16 & negative ions (Groups 16 & 17)17)

Groups 14 & 15 may lose, gain Groups 14 & 15 may lose, gain or share electronsor share electrons

Group 18 consists of the noble Group 18 consists of the noble gases, non-reactive elementsgases, non-reactive elements

4 Basic Types of Elements4 Basic Types of Elements

Metals:Metals: found on the left and center of the found on the left and center of the Periodic Table Periodic Table

Non-metals:Non-metals: found on the right side of the found on the right side of the Periodic Table Periodic Table

Metalloids:Metalloids: found along the stair-step line found along the stair-step line Synthetic:Synthetic: made in the laboratory and not made in the laboratory and not

yet found in nature – many of the Actinide yet found in nature – many of the Actinide and Lanthanide series and very large and Lanthanide series and very large atomic # elements.atomic # elements.

Properties of Elements - Properties of Elements - MetalsMetals

Metals are: Metals are: Conductors Conductors Lustrous Lustrous Electron Electron

donors donors Malleable Malleable Ductile Ductile

Na+

Where are the Where are the metallic elements?metallic elements?

Left of the Stair-step line!

Properties of NonmetalsProperties of Nonmetals

Nonmetals are brittle, insulators, Nonmetals are brittle, insulators, electron acceptorselectron acceptors

Usually form negative ions (except H) Usually form negative ions (except H) Many are gases at room temperature Many are gases at room temperature Found to the right of the stair-step line Found to the right of the stair-step line

Which of the following groups Which of the following groups contains members with similar contains members with similar chemical reactivity?chemical reactivity?

A A Li, Be, CLi, Be, C

BB Be, Mg, Sr Be, Mg, Sr

C C Sc, Y, ZrSc, Y, Zr

D D C, N, O C, N, O

Lets look at the Table provided.Lets look at the Table provided.

To have similar To have similar chemical chemical properties of any properties of any kind, they must kind, they must be in the same be in the same Group or Family. Group or Family.

Groups are Groups are columns, so the columns, so the answer would be answer would be

BB

Chemical ReactivityChemical Reactivity Metals increase Metals increase

in reactivity left in reactivity left and down. and down.

Nonmetals Nonmetals become more become more reactive up and reactive up and to the right. to the right.

Most reactive Most reactive metal is? metal is?

Most reactive Most reactive nonmetal is? nonmetal is?

Fr

F

Diatomic Elements – Diatomic Elements – Nonmetals that exist as Nonmetals that exist as

moleculesmolecules

7 Elements are di- (2) atomic (atoms) 7 Elements are di- (2) atomic (atoms) The easy way to remember them is by The easy way to remember them is by

the name the name

Br I N Cl H O F Br I N Cl H O F

C o m p o u n d sC o m p o u n d s C o m p o u n d sC o m p o u n d s

Pure substances that can be Pure substances that can be broken down by a chemical broken down by a chemical reaction. reaction.

Molecules are the smallest Molecules are the smallest particle of a compound that particle of a compound that retains its properties and it is retains its properties and it is composed of 2 or more composed of 2 or more atoms.atoms.

What about What about MOLECULES?MOLECULES?

These are These are MULTI-ATOM MULTI-ATOM particles, ex: particles, ex:

COCO22

Compounds:Compounds:A combination of two or more A combination of two or more

elements chemically combined into a elements chemically combined into a new substance. A compound can new substance. A compound can only be separated by a chemical only be separated by a chemical

reaction.reaction.Common compounds:

Water H2O

Salt NaCl

Carbon dioxideCO2

Names of Compounds – Ionic Names of Compounds – Ionic

Ionic compounds consist of cations Ionic compounds consist of cations (positive ions) and anions (negative ions). (positive ions) and anions (negative ions).

A Roman numeral in parentheses, A Roman numeral in parentheses, preceded by the name of the element, is preceded by the name of the element, is used for elements that can form more than used for elements that can form more than one positive ion. This is usually seen with one positive ion. This is usually seen with metals.metals.

FeFe2+2+ Iron (II) Cu Iron (II) Cu++ Copper (I) Copper (I)FeFe3+3+ Iron (III) Cu Iron (III) Cu2+2+ Copper (II) Copper (II)

Ionic compounds – naming cont. Ionic compounds – naming cont.

The The -ide-ide ending is added to the name of a ending is added to the name of a single element when it becomes an ion of single element when it becomes an ion of that element. that element. Oxide, Nitride, SulfideOxide, Nitride, Sulfide etc. etc.

Examples: NaCl sodium chlorideExamples: NaCl sodium chloride MgOMgO magnesium oxidemagnesium oxide

AlAl22SS3 3 aluminum sulfidealuminum sulfide

CoClCoCl22 cobalt(II) chloride cobalt(II) chloride

Formula Writing-With Polyatomic Formula Writing-With Polyatomic IonsIons

Write formulas for the following:Write formulas for the following:

AlAl+3+3 SOSO442-2-

ALAL22(SO(SO44))33 aluminum sulfatealuminum sulfate

CaCa+2+2 ClO ClO331-1-

Ca(Cl0Ca(Cl033))22 calcium chlorate calcium chlorate

Covalent Compounds – Covalent Compounds – Names are the FormulasNames are the Formulas

These are nonmetal to nonmetal These are nonmetal to nonmetal compounds. compounds.

The name tells you the formula. The name tells you the formula.

Carbon dioxide Carbon dioxide 1 C and 1 C and 22 O O

COCO22

Special Names of Compounds: Special Names of Compounds: BasesBases

Bases end in the Bases end in the hydroxide anionhydroxide anion

OHOH- -

They are named They are named with the metal with the metal and hydroxide. and hydroxide.

NaOH is sodium NaOH is sodium hydroxide hydroxide

Name the following:

KOH

Potassium hydroxide

Mg(OH)2

Magnesium Hydroxide

Special Names of Compounds:Special Names of Compounds:AcidsAcids

Acids that are two elements are named Acids that are two elements are named Hydro-Hydro-nonmetal root wordnonmetal root word –ic Acid such –ic Acid such as as HCl hydroHCl hydrochlorchloric acid ic acid

Oxyacids are named from the negative Oxyacids are named from the negative ion: -ate becomes –ic and -ite becomes –ion: -ate becomes –ic and -ite becomes –ous. ous.

HH22SOSO33 sulfur sulfurousous acid acid HH22SOSO44 sulfur sulfuricic acid acid

Law of Conservation of Matter Law of Conservation of Matter

Matter cannot be created or destroyed. Matter cannot be created or destroyed. The total mass of the substances before they The total mass of the substances before they

react is equal to the total mass of the products. react is equal to the total mass of the products.

Chemical Reactions Chemical Reactions Since matter cannot be Since matter cannot be

created or destroyed, created or destroyed, chemical reactions chemical reactions must be balanced in must be balanced in terms of mass. terms of mass.

The amount of mass The amount of mass you start with must you start with must be equal to the mass be equal to the mass of the products. of the products.

Reactants Reactants Products Products

100g total = 100g total100g total = 100g total

Liquid 1 and Liquid 2 react to produce a solid and a gas. Which of the following

expressions correctly shows how to

determine the mass of the gas? F (mass of Liquid 1 + mass of Liquid 2) − (mass

of solid) G (mass of Liquid 1 + mass of Liquid 2) + (mass

of solid) H (mass of Liquid 1 × mass of Liquid 2) ÷ (mass

of solid) J (mass of Liquid 1 − mass of Liquid 2) ÷ (mass

of solid)

F

(mass of Liquid 1 + mass of Liquid 2) − (mass of solid)=mass of gas!!!

Reactants =Products

According to the law of conservation of According to the law of conservation of mass, how much zinc was present in the mass, how much zinc was present in the

zinc carbonate?zinc carbonate?

A A 40 g 40 g B B 88 g 88 g CC 104 g 104 g D D 256 g256 gSince matter cannot 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 student placed a piece of steel wool inside a test tube and heated the test tube and its contents over a Bunsen burner flame for 3 minutes. The student repeated this procedure two more times and collected the following data.

Before HeatingTrial 1 Trial 2 Trial 3

Test Tube 20.0 g 19.4 g 19.5 g

Steel Wool 3.1 g 2.2 g 3.5 g

After Heating Trial 1 Trial 2 Trial 3

Test Tube 20.0 g 19.4 g 19.5 g

Steel Wool 5.0 g 3.5 g 5.6 g

Which of the following most likely explains why the steel wool gained mass?

A. The student’s measurements lacked precision.

B. The steel wool became denser with heating.

C. The student needed to perform more trials.

D. The steel wool reacted with oxygen.

D. The steel wool reacted with oxygen.

How do you know this happened?

When an object burns it is combining with oxygen.

Burning Steel WoolBurning Steel Wool

Fe + OFe + O22 Fe Fe22OO33

Is this a correctly written Is this a correctly written equation?equation?

Why or why not?Why or why not?

Chemical EquationsChemical Equations Whole numbers written in front of formulas are Whole numbers written in front of formulas are

called called coefficientscoefficients. For example, . For example, 44 C C66HH1212OO6 6

indicates that there are indicates that there are 44 molecules of glucose molecules of glucose sugar.sugar.

To determine how many total atoms of each To determine how many total atoms of each element are present, multiply the element are present, multiply the coefficientscoefficients by the by the subscriptssubscripts for each element. for each element.

44 C C66HH1212OO66 would contain 24 atoms of carbon would contain 24 atoms of carbon

((4 4 x x 66), 48 atoms of hydrogen (), 48 atoms of hydrogen (44 x x 1212), and 24 ), and 24 atoms of oxygen (atoms of oxygen (44 x x 66).).

To balance equations:To balance equations: The number of atoms of each type of element The number of atoms of each type of element

on the reactant side (left of the arrow) must be on the reactant side (left of the arrow) must be equal those on the product side (right side of equal those on the product side (right side of the arrow).the arrow).

2 H2 H22 + O + O2 2 2 H 2 H22OO

There are 4 hydrogen atoms on the left (There are 4 hydrogen atoms on the left (22 H H22) )

and 4 hydrogen atoms on the right (and 4 hydrogen atoms on the right (22 H H22O)O)

There are 2 atoms of oxygen (OThere are 2 atoms of oxygen (O22) on the left ) on the left

and 2 atoms of oxygen on the right (and 2 atoms of oxygen on the right (22 H H22O). O).

When a subscript or coefficient is missing, it is When a subscript or coefficient is missing, it is understood to be 1.understood to be 1.

K + HK + H22O O KOH + H KOH + H22

What is the coefficient for HWhat is the coefficient for H22O when O when

the above equation is balanced?the above equation is balanced? A A 11 BB 2 2 C C 33 D D 44

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

22

C

Fe + OFe + O22 Fe Fe22OO33

Balance the equation.Balance the equation.

4Fe + 3O4Fe + 3O22 2Fe 2Fe22OO33

So, back to burning steel wool…..

Physical, Physical, ChemicalChemical or or NuclearNuclear ChangesChanges

Changes in Matter – Changes in Matter – Physical or Chemical?Physical or Chemical?

Physical changes are changes in the state of Physical changes are changes in the state of matter. They do not change the substance. matter. They do not change the substance. (Melting, boiling, condensing, freezing, cutting) (Melting, boiling, condensing, freezing, cutting)

Chemical changes are reactions that result in Chemical changes are reactions that result in new products with new properties. new products with new properties.

Physical changesPhysical changes do not change do not change chemical composition chemical composition of the substance. of the substance.

The state or phase of The state or phase of the matter may the matter may change. change.

Cutting a piece of Cutting a piece of wood does not wood does not change the wood, it is change the wood, it is simply smaller.simply smaller.

Chemical changesChemical changes are also are also called chemical reactions.called chemical reactions.

When a different When a different substance is produced substance is produced than what was present at than what was present at the start, a chemical the start, a chemical change has occurred.change has occurred.

Nuclear Changes: Fission and Nuclear Changes: Fission and FusionFusion

Fusion occurs when Fusion occurs when the nucleus of one the nucleus of one atom is joined by the atom is joined by the nucleus of another. nucleus of another.

This is the reaction This is the reaction that occurs on the sun that occurs on the sun and stars. and stars.

It produces extreme It produces extreme energy release. energy release.

Fission occurs when the Fission occurs when the nucleus of an atom nucleus of an atom ejects particles and ejects particles and energy when hit by a energy when hit by a subatomic particle such subatomic particle such as a neutron. as a neutron.

This also causes a This also causes a release of extreme release of extreme energy and is the basis energy and is the basis of atomic energy plants of atomic energy plants and bombs. and bombs.

Nuclear RadiationNuclear Radiation

Alpha radiation consists of Alpha radiation consists of helium-4 nuclei and is nuclei and is readily stopped by a readily stopped by a sheet of paper. sheet of paper.

Beta radiation, consisting of Beta radiation, consisting of electrons, is halted by an , is halted by an aluminum plate. aluminum plate.

Gamma radiation has the Gamma radiation has the highest energy and highest energy and shortest wavelengthshortest wavelength, , therefore it is most therefore it is most damaging to living cells.damaging to living cells.

Number of Half-livesTime-years

% Strontium-90 remaining

% Strontium-90 that has decayed

0 0 100 0

1 28 50 50

2 56 25 75

3 84 12.5 87.5

4 112 6.25 93.75

5 140 3.125 96.875

6 168 1.5625 98.4375

1. Consider strontium-90 which has a half-life of approximately 28 years. Initially, at time t=0, the sample is 100% strontium-90

After 28 years, only half the original amount of strontium will remain: ½ x 100% = 50% After another 28 years, only half of this amount of strontium-90 will remain: ½ x 50% = 25%

After another 28 years, only half of this amount of strontium will remain: ½ x 25% = 12.5% and so on.

At any given time, the amount of strontium-90 that has undergone decay can be calculated:amount of strontium-90 decayed = the original amount - the amount remaining.

Half-Life!!!Half-Life!!!

The amount of time it takes for half of a sample of radioactive material to decay.

Different elements are used in Different elements are used in radioactive dating because they radioactive dating because they have differenthave different

A half-lives.A half-lives.B isotopes.B isotopes.C compositions of DNA.C compositions of DNA.D sedimentation rates.D sedimentation rates.

Explain why!Explain why!

Carbon-14 has a half-life of ~5600 years.Carbon-14 has a half-life of ~5600 years.

We haven’t We haven’t forgotten forgotten

about about mixtures!mixtures!

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 :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 :

• Each substance within the mixture retains its own Each substance within the mixture retains its own properties. properties.

• Substances can be present in any amount. Substances can be present in any amount.

• Substances within the mixture can be separated by Substances within the mixture can be separated by physical means. physical means.

There are two types of There are two types of mixtures: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 Decide if the substance is Element, Compound , or Mixture?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

6. Copper

7. Soft Drinks

8. Steel

9. Rain

10. Ice-cream

6. Element

7. Solution/Mixture

8. Solution/Mixture

9. Mixture

10. Mixture

Let’s try a few more!

Separating Mixtures – Physical Separating Mixtures – Physical ChangesChanges

Separation of mixtures Separation of mixtures could be: could be:

Magnetic removal (if Magnetic removal (if there is Fe, Ni, Co) there is Fe, Ni, Co)

Filtration (if there are Filtration (if there are large particles)large particles)

Hand sorting particles Hand sorting particles Decanting (pouring off the Decanting (pouring off the

less dense liquid)less dense liquid) Distillation-evaporation Distillation-evaporation

and condensationand condensation

Another technique for Another technique for separating mixtures:separating mixtures:

Evaporation:Evaporation: changing from changing from

a liquid to a liquid to vapor state– vapor state–

leaves behind leaves behind the other the other

component.component.

What about weathering and What about weathering and condensation?condensation?

Weathering is Weathering is primarilyprimarily a physical a physical change!!!change!!!

Condensation and Condensation and evaporation are evaporation are always physical always physical changes!!!changes!!!

Mixtures may be Mixtures may be Solutions!Solutions!

Mixtures may be Mixtures may be Solutions!Solutions!

SolventSolvent-the most abundant substance -the most abundant substance in the solution. in the solution.

SoluteSolute-the least abundant substance -the least abundant substance in the solution.in the solution.

HomogeneousHomogeneous: : You can not see any You can not see any particles of either part! (solutions)particles of either part! (solutions)

HeterogeneousHeterogeneous: : substances exist in substances exist in distinct phases (not solutions, maybe distinct phases (not solutions, maybe colloids or suspensions?)colloids or suspensions?)

So, what is a suspension or So, what is a suspension or colloid (hint: heterogeneous colloid (hint: heterogeneous

mixture)? mixture)? Colloids have small Colloids have small

particles that are not particles that are not visible by just looking. visible by just looking. An example would be An example would be coffee. coffee.

However, they show However, they show the Tyndall Effect the Tyndall Effect (reflection of light). (reflection of light).

They can not be They can not be separated by filtering. separated by filtering.

o Suspensions have larger particles, often visible in size.

o The particles can be filtered out.

o It scatters light (like fog) – No Tyndall Effect.

o If left undisturbed, the particles will settle to the bottom.

Preparing SolutionsPreparing Solutions

Brainstorm:Brainstorm:Solutes are mixed with Solutes are mixed with

solvents to create solvents to create solutions-how can the solutions-how can the rate of dissolving be rate of dissolving be increased?increased?

All of these can affect the rate at which a All of these can affect the rate at which a solid dissolves in water solid dissolves in water exceptexcept — —

AA decreasing air decreasing air pressurepressure

B B stirring the waterstirring the water

C C increasing the increasing the temperature of the temperature of the waterwater

D D using larger crystals using larger crystals of the solidof the solid

The three methods to increase the The three methods to increase the rate of solution for a solid are?rate of solution for a solid are?

Heat it! C Heat it! C speeds itspeeds it Crush it! D Crush it! D slows itslows it Stir it! B Stir it! B speeds itspeeds it

So this eliminates So this eliminates choices B, C & D choices B, C & D

Which will NOT Which will NOT change it? change it?

A A

Answer choices were: Answer choices were:

AA decreasing air pressure decreasing air pressure

B B stirring the waterstirring the water

C C increasing the increasing the temperature of the temperature of the waterwater

D D using larger crystals of using larger crystals of the solidthe solid

The three methods to The three methods to increase the rate of solution increase the rate of solution

for a solidfor a solid are?are?Heat it! Heat it! Increase Increase surface surface area! area!

Stir it!Stir it!

A 0.2 g crystal of gypsum dissolves very A 0.2 g crystal of gypsum dissolves very slowly in 100 mL of water while the water is slowly in 100 mL of water while the water is stirred. Which of these would cause the stirred. Which of these would cause the gypsum to dissolve faster?gypsum to dissolve faster?

F F Decreasing the Decreasing the water temperaturewater temperature

G G Stopping the stirringStopping the stirring

H H Lowering the air Lowering the air pressurepressure

JJ Crushing the crystal Crushing the crystal

What are the 3 ways to What are the 3 ways to increase the rate at increase the rate at

which a solid which a solid dissolves? dissolves?

Heat it! Heat it!

Crush it! Crush it!

Stir it! Stir it!

ANSWER? ANSWER?

JJ

How much solute will dissolve?How much solute will dissolve?

A solubility curve shows A solubility curve shows the amount of each solute the amount of each solute that will dissolve in 100g that will dissolve in 100g HH220 at each temperature. 0 at each temperature.

Saturated is on the line. Saturated is on the line. Unsaturated is below the Unsaturated is below the

line. line. Supersaturated is above Supersaturated is above

the line. the line. Gra

ms

solu

te/1

00 g

H2O

At which At which temperature temperature do KBr and do KBr and KNOKNO33 have have

the same the same solubility?solubility?

A A 27°C27°C

BB 48°C 48°C

C C 65°C65°C

D D 80°C80°C

Dissolved Gases in WaterDissolved Gases in WaterTo survive, trout require high

levels of oxygen dissolved in water. Which of the following changes would most likely result in a decrease in the dissolved oxygen levels of a lake?

A. Above average rainfall for the surrounding area

B. A decrease in boating on the lake

C. An increase in water temperature of the lake

D. Less construction around the lake

Try this Try this one!one!

According to the graph, about how muchhemoglobin would be saturated at an O2

pressure of 7.3 kPa?A 32%B 67%C 89%D 92%

Concentrated or Dilute? Concentrated or Dilute?

A A concentrated concentrated solution has as little solution has as little solvent as possible. solvent as possible.

A A dilutedilute solution has solution has added solvent. added solvent.

After adding more After adding more solvent, there is still solvent, there is still the same mass of the same mass of solute that you started solute that you started with. with.

Acids Acids and and Bases Bases are solutions!!!are solutions!!!

pH RangepH Range

0 1 2 3 4 5 6 7 8 90 1 2 3 4 5 6 7 8 9 10 11 12 13 1410 11 12 13 14

NeutralNeutral

[H[H++]]>>[OH[OH--]] [H[H++] = [OH] = [OH--]]

[OH[OH--]]>>[H[H++]]

Acidic Basic

On the pH scale, values below 7 are acidic, a value of 7 is neutral, and values above 7 are basic.

pHpH is a measure of the is a measure of the Strength of Acids & BasesStrength of Acids & Bases

Acids have 0-6.99 pHAcids have 0-6.99 pH Bases have 7.01-14 pHBases have 7.01-14 pH Acids contain more HAcids contain more H++

(H(H33O O ++) ions, bases ) ions, bases

contain more OHcontain more OH-- ions ions Litmus turns red in Litmus turns red in

acids and blue in bases acids and blue in bases Phenothalein turns pink Phenothalein turns pink

in a base and stays in a base and stays clear in acids. clear in acids.

Higher pH levels means?Higher pH levels means?Two clear solutions are placed in separateTwo clear solutions are placed in separate

beakers. The first solution has a pH of 4, and the pH beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. Ifof the second solution is unknown. If

the two solutions are mixed and the resultingthe two solutions are mixed and the resulting

pH is 5, the second solution must have — pH is 5, the second solution must have —

A A fewer suspended solidsfewer suspended solids

B B a lower temperaturea lower temperature

C C more dissolved salt (NaCl) particlesmore dissolved salt (NaCl) particles

DD a higher concentration of OH– ions 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.

Solution pH

Distilled water 7.0

Baking soda 8.6

Lemon juice 2.4

Milk 6.8

Which conclusion is supported by the information in the table?

A. Distilled water has more ions than the other substances.

B. Baking soda can be used to neutralize lemon juice. C. Milk conducts electricity better than the other

substances. D. Baking soda and milk react to produce a strong base.

So……

Beaker X5 g of salt and 200 mL of distilled water

Beaker Y15 g of salt and 200 mL of distilled water

A student mixes two different saltwater solutions as shown in the chart above. When comparing properties of the two solutions, all of the following were found to be different for the two solutions except:

A. pH B. freezing point C. density D. conductivity

Physical Properties of Solutions

Which one?

A. pH B. freezing pointC. densityD. conductivity

How does the presence of more salt affect each property?

Increases density, increases conductivity and decreases freezing point. That leaves choice “A. pH”, more salt (NaCl) does not affect the HH++ or OHor OH- - concentration!concentration!

What types of solutions conduct What types of solutions conduct electricity?electricity?

Sugar/water?Salt/water?Sea water?

Distilled water?Tap water?

ChemistryChemistry

THE END!!!