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End of Year Review

Scientific Method and Properties of Matter and Chemistry8th Grade Science CurriculumEssential Question #79How do I set up an experiment?Lab SafetyWhat are the potential hazards? Broken glassSpillsFireElectrical shocksCan you think of other hazards?

Essential Question #80How do I safely manipulate materials and equipment?Lab SafetyFollow safety rules covered at the beginning of the year.Know these rules!Follow teacher instructions.What else applies?

How do I safely manipulate materials and equipment and conduct appropriate procedures?

Essential Question #80How do I safely manipulate materials and equipment?Know all the safety rules of the safety contract and classroom.Essential Question #81How do I conduct appropriate procedures?Scientific MethodAsk a Question Do Background Research Construct a Hypothesis Test Your Hypothesis by Doing an Experiment Analyze Your Data and Draw a Conclusion Communicate Your Results Essential Question #81How do I conduct appropriate procedures?Know and use the Scientific Method.Essential QuestionWhat types of questions can be answered through scientific investigation?Scientific MethodWhat types of questions can be answered through scientific investigations?How do I set up an experiment?Identify and create questions and hypotheses that can be answered through scientific investigations.Data must be measurable.Understand appropriate experimental procedures. Can you give some examples?

Essential Question #82What types of questions can be answered through scientific investigation?Questions must be testable and measurable.No opinion can be used as data.Analyzing DataHow do you analyze large amounts of data?Line GraphBar GraphPie ChartCan you think of other ways to analyze data?

Essential Question #83What are dependent and independent variables and how are they related?Analyzing DataWhat are dependent and independent variables and how are they related? Independent variable is the variable being tested. Can be changed to get different observations. Always the X axisDependent variable results depend on the independent variable. Changes based on changes in the independent variable. Always the Y axis.

Dependent variableIndependent variableEssential Question #83What are dependent and independent variables and how are they related?Can you explain? Essential Question #84Why do I need a control?Scientific MethodWhy do I need to have a control?Controls are not affected by the independent variable.Gives data unaffected by the variable being tested.You need to know what would happen if nothing was done to the subject being tested

Essential Question #84Why do I need a control?You need to know what the results would be without the variable being tested.Essential Question #85How many variables do I manipulate or change?ExperimentationHow many variables do I manipulate (or change)? AlwaysOnly ONE

Essential Question #85How many variables do I manipulate or change?Just one or you dont know which one provided the measurable data.Essential Question #79How do I set up an experiment?Class discussionProperties of MatterMatterHas mass and volumeMassAmount of matter contained in a substanceMeasured in grams (g)VolumeAmount of space an object occupiesMeasured in liters (L)Changes in MatterPhysical ChangeA change in a substance that doesnt change its identityExample: Ice melting or chopping woodChemical ChangeA change in which one or more substances combine or break apart to form new substancesExample: burning paper or putting an acid in a base

Essential Question #86How is density used to compare different substances? Properties of MatterHow is density used to compare different substances? Density is the quantity of matter that is packed into a fixed space.D = m/v (OR) gram/literDensity = Mass/VolumeDensity > 1 (sinks)Density < 1 (floats)Buoyancy the ability of a fluid to exert an upward force on an object that is immersed in the fluid

Essential Question #86How is density used to compare different substances? Density is different for every material. If you know a materials density, it may help identify the material.Essential Question #87How are boiling points and melting points used to compare different substances? Properties of MatterIn matter, how does temperature change? All atoms and molecules move.The faster they move, the higher the temperatureChange in temperature occurs by speeding up or slowing down particle movement

States of MatterGasesOccur when particles move freely (are fluid)Volume changes by being easily compressed or expandedA gas maintains the shape of its container If these particles are heated, they move faster and need more space. This is why heat expands volume and decreases density.Created when substances boil or evaporate.If the particles slow down, they can become a liquid. (condensation)

States of MatterLiquidsOccur when particles move freely (fluid) but are bonded to each other.Volume is constant but shape changesMovement is slower than that of gases.If these particles are heated, they easily escape and become gas. (evaporation or boiling)If they slow down, they easily get trapped in place and become a solid. (freezing)

States of MatterSolidsOccur when particles vibrate in placeHave a definite shape and volumeDifferent substances have different freezing points.Water becomes solid at 0C if heat is taken away. This is freezing.Iron becomes solid at 1538C if heat is taken away. This is also freezing.

Of the states of matter, gas is the only state that Is fluidHas massIs highly compressibleHas a definite shapeOf the states of matter, gas is the only state that Is fluidHas massIs highly compressibleHas a definite shapeStates of MatterTerms to RememberEvaporation

Boiling

Condensation

Freezing

SublimationLiquid is changed into a vapor.Liquid is changed into a vapor by adding heatGas cooling and becoming liquidLiquid cooling and becoming a solidSolid turning directly into a gas without becoming liquid (example: dry ice)Properties of MatterHow are boiling/melting points used to compare different substances? Different substances have different boiling/melting points.0C is the melting and freezing point of water.100C is the boiling point of water.Substances in water can change the boiling/melting points

Essential Question #87How are boiling points and melting points used to compare different substances?If you can find the boiling and melting point of a substance, the information may help you identify that substance. All materials have consistent boiling and melting points.Essential Question (#77)How does water hold heat? (We already answered, but lets review again)Properties of MatterSpecific HeatThe amount of energy needed to raise one gram of a substance by one degree CelsiusWater has a very high specific heatThis means it can absorb a lot of heatThat is why water works well to put out a fire

Essential Question (#77)How does water hold heat? Because of the strength of hydrogen bonds, water will hold a lot of heat. Since there is so much water on Earth, it helps keep our climates from going to extreme temperatures. Which of the following has the least effect on lake water temperature?

The depth of the waterThe angle of incoming sun raysThe number of fish in the lakeThe lakes surface areaWhich of the following has the least effect on lake water temperature?

The depth of the waterThe angle of incoming sun raysThe number of fish in the lakeThe lakes surface areaEssential Question #88How is solubility used to compare different substances?Properties of MatterWhat is a solution?

A mixture formed when one substance dissolves another.What is a solvent?

A substance that dissolves another substanceWhat is a solute?A substance that is dissolved by the solvent.What is a saturated solution?Saturated: has as much solute as a solvent can holdProperties of MatterHow is solubility used to compare different substances? Is the substance a solvent?Is the substance a solute?Does it dissolve in water?Does it dissolve in oil?What else do you know about solubility?Insoluble means that some substances are not soluble

Essential Question #88How is solubility used to compare different substances?If you find what will dissolve a substance and how fast it dissolves, it can help you identify the substance. All substances have unique dissolving qualities.

Properties of Matter How can temperature affect the speed a solute will dissolve in a solvent?Remember, heat is the movement or vibration of atoms and molecules.Rapid movement of the particles of the solvent will speed up the rate of the solute breaking up (dissolving).

Properties of MatterChromatography: a means of separating a mixture based on polarity and solubility

Chromatography of chlorophyllChromatography of inksupload.wikimedia.org www.membrane-solutions.comEssential Question #89How is malleability used to compare different substances?Essential Question #90Which material is the most/least malleable?Properties of MatterHow is malleability used to compare different substances? Malleability is the ability to be hammered into a sheet.Metals are more malleable.Can you give an example of a substance that is malleable?

Essential Question #89How is malleability used to compare different substances?A substance is malleable or not. Some substances are more malleable than others. If a substance is malleable, you know it is probably a metal.Essential Question #90Which material is the most/least malleable?Metals are the most malleableNonmetals are the least malleable.Essential Question #91How is ductility used to compare different substances? Properties of MatterDuctility - the ability to be stretched into a thin wire Some substances are more ductile than others.Can you give an example of a substance that is ductile?

Essential Question #91How is ductility used to compare different substances?Ductility - the ability to be stretched into a thin wire Some substances are more ductile than others.57ChemistryEssential Question #92What is the structure of an atom?59ChemistryAtom: the smallest unit of matter that retains the identity of the substanceThree particles:ProtonsNeutronsElectrons

Nucleusalternativealtruist.wordpress.com60ChemistryStructure of an AtomNucleus: contains protons and neutrons; the total number of particles in the nucleus is the atomic mass numberProton: subatomic particle with a positive charge and located in the nucleus of the atom. The number of protons gives the atom its identity (atomic number)Neutron: subatomic particle with no charge, the same mass as a proton, and located in the nucleus of the atom61ChemistryStructure of an Atom

www.chemicalconnection.org.ukThe structure of an hydrogen atom, helium atom, lithium atom and a sodium atom62ChemistryStructure of an AtomElectron: subatomic particle with a negative charge and located outside the nucleus

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commons.wikimedia.org63Where do you find the number of particles of atoms in a periodic table?

Structure of an Atom

kaffee.50webs.com64ChemistryStructure of an AtomAtomic NumberThe number of protons in the nucleus of an atomThis number identifies the atomIncreases as you go to the right in periods and starts again on the left of the next period

www.chemicalconnection.org.ukAtomic Number = Protons 1 2 3 11 65ChemistryStructure of an AtomAtomic Mass Number: the number of protons and neutrons in the nucleus of an atomAs the atomic number increases, usually, so does the massAs the atomic number increases, usually, so does the densitymass number = protons + neutronsThe number of neutrons depends on which isotope of the element you are using.

Atomic Mass Numbers H-1 H-2 H-3for the isotopes of hydrogen66ChemistryStructure of an AtomAtomic Mass: the average mass number of all isotopes of an atom. Round this number to find the mass number of the atom.

Most hydrogen atoms have only a proton (protium). But since there are two isotopes of hydrogen, (deuterium and tritium) the atomic mass is a little more than one. education.jlab.org

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67ChemistryStructure of an AtomTo find the numbers of the different particles of an element:Atomic Number = Protons atomic number 6 = 6 protonsElectrons = Protons 6 electrons = 6 protons

Atomic Mass Protons = Neutrons atomic mass (rounded) 12 6 protons = 6 neutrons

iss.cet.eduEssential Question #92What is the structure of an atom?Protons (+) and Neutrons (o) inside nucleusElectrons (-) surrounding the nucleus

69Looking at the block of the element Carbon on the periodic table, the number 6 represents?

Atomic mass of the element carbonAtomic number of the element carbonNumber of neutrons in the element carbonNumber of valence electrons in the element carbon70Looking at the block of the element Carbon on the periodic table, the number 6 represents?

Atomic mass of the element carbonAtomic number of the element carbonNumber of neutrons in the element carbonNumber of valence electrons in the element carbonEssential Question #93What are chemicals? 72ChemistryWhat is a chemical?Chemical: any substance made of atoms Element: a substance that cannot be broken down into simpler substances by ordinary chemicals meansPeriodic Table: an arrangement of elements in order of increasing atomic numbers that demonstrates the periodic patterns that occur among the elementsEssential Question #93What are chemicals?Anything that is made of atoms. You are made of chemicals. Because zinc can combine with other substances but cannot be changed into a simpler substance by an ordinary chemical process, zinc is classified as -

A compoundA mixtureAn elementAn acidBecause zinc can combine with other substances but cannot be changed into a simpler substance by an ordinary chemical process, zinc is classified as -

A compoundA mixtureAn elementAn acidEssential Question #94How are the elements categorized in the periodic table?Essential Question #95What happens to the number of protons as you move to the right on a periodic table?Essential Question #96Which material is the most/least dense?Remember: Atomic Number = Number of Protons

Atomic Numbers increase as they move across the periodic table from left to right.

Atomic mass affects density. The greater the atomic mass, the greater the density.80

facstaff.gpc.eduEssential Question #95What happens to the number of protons as you move to the right on a periodic table?The number of protons, like the atomic number, increases as they move from left to right.Essential Question #96Which material is the most/least dense?Hydrogen is the least dense of all elements with an atomic mass of one.As the elements go from left to right in the periods, atomic mass increases so density does also.83Structure of the Periodic TablePeriod: elements that occur in a horizontal row on the periodic table; there are eight periods

Group or Family: elements that occur in a vertical column on the periodic table; there are eighteen groups

periodgroup or family energy.comEssential Question #97How does the periodic table help you to identify the properties of the elements?85Alkali MetalsFirst column in the periodic tableThey have one electron in the outer shellThis characteristic makes them the most reactive metals

www.learner.org86Alkaline Earth MetalsSecond column in the periodic tableHave two electrons in the outer shell Second most reactive metals in the periodic table

www.learner.orgwww.learner.orgEssential Question #98Which materials provide the best/worst electrical conductivity?Essential Question #99Which material is the most/least magnetic?89MetalsAn element below and to the left of the stair-step line of metalloidsAbout 80% of the known elements are metalsMost are shiny and conduct heat and electricityMalleable Low specific heat (absorbs heat quickly)Many metals demonstrate magnetismAre pink in the chart

media-2.web.britannica.com90A mixture of iron filings and sulfur can easily be separated by -

Placing the mixture in water.Performing a chemical reaction.Heating the mixture.Using a magnet.91A mixture of iron filings and sulfur can easily be separated by -

Placing the mixture in water.Performing a chemical reaction.Heating the mixture.Using a magnet.92Which best describes why metals are used for making pots and pans that are used for cooking?

Metals have low specific heats and high melting points.Metals have high specific heats and low melting points.Metals have low specific heats and low melting points.Metals have high specific heats and high melting points.93Which best describes why metals are used for making pots and pans that are used for cooking?

Metals have low specific heats and high melting points.Metals have high specific heats and low melting points.Metals have low specific heats and low melting points.Metals have high specific heats and high melting points.94Which property of metals allows them to be used to make coins that have the same thickness?

Electrical conductivityDensityMalleabilitySpecific heat95Which property of metals allows them to be used to make coins that have the same thickness?

Electrical conductivityDensityMalleabilitySpecific heat96MetalloidsAn element with properties of both metals and nonmetals located along the stair-step line on the right side of the periodic tableMost of the elements touching the stair-step lineGreen in the chart9696

media-2.web.britannica.com97NonmetalsAn element above and to the right of the stair-step line of metalloidsDullNon-conductive of heat or electricity so they make good insulatorsNon malleableBlue in the chart Non magnetic

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media-2.web.britannica.comEssential Question #98Which materials provide the best/worst electrical conductivity?Metals are the best conductorsNonmetals are the worst conductorsEssential Question #99Which material is the most/least magnetic?Metals are the most magnetic Nonmetals are the least magnetic.100100Insulation materials reduce heat loss because they -

Are poor conductorsBlock out the sunReduce evaporationPromote convection101Insulation materials reduce heat loss because they -

Are poor conductorsBlock out the sunReduce evaporationPromote convection102Halogens

Seventeenth column in the periodic table (next to last)Needs one electron to fill the outer shell Most reactive nonmetals in the periodic table

www.learner.org103Noble Gases Full outer shellsThe least reactive of all elementsEighteenth column (last group)

www.learner.orgEssential Question #97How does the periodic table help you to identify the properties of the elements?Due to the arrangement of the outer electrons, elements in the same group or family have similar characteristics.Essential Question #94How are the elements categorized in the periodic table?Groups or families and periodsMetals, nonmetals, and metalloidsAlkali metalsAlkaline earth metalsTransition metalsHalogensNobel gasesEssential Question #100In a chemical or physical change, how does volume change? 107Changes in MatterPhysical ChangeA change in a substance that doesnt change its identityExample: Ice melting or chopping woodChemical ChangeA change in which one or more substances combine or break apart to form new substancesExample: burning paper or putting an acid in a baseBonds are broken and/or made in a chemical change (reaction)

Changes in MatterPhysical ChangeChemical Change

In a physical change, no change in volume occurs in solids and liquids. Gases however can expand when heated.

In a chemical change, if the new products created are more or less dense than the reactants before the reaction, there is a change in volume. An example is when a log burns, the gases given off have a greater volume than the original wood.Essential Question #100In a chemical or physical change, how does volume change?Class discussion 110110Which best describes the physical change of an aluminum soda can after it is crushed?

There is a change in the mass of the can.There is a change in the weight of the can.There is a change in the volume of the can.There is a change in the specific heat of the can.111Which best describes the physical change of an aluminum soda can after it is crushed?

There is a change in the mass of the can.There is a change in the weight of the can.There is a change in the volume of the can.There is a change in the specific heat of the can.112112Which process is a physical change?

Rusting ironBurning coalTarnishing silverMelting ice113Which process is a physical change?

Rusting ironBurning coalTarnishing silverMelting iceEssential Question #101How do elements combine to produce compounds?Essential Question #102Which element is found in all living or once living things?ESSENTIAL QUESTION #103Which materials are the most/least soluble?117Chemical BondingTwo Kinds1. Ionic Bonding - formed when two or more atoms gain or lose electrons and then become charged

ffdgfgwww.es.ucsc.eduSince ions are charged particles, they are also easily dissolved in waterESSENTIAL QUESTION #103Which materials are the most/least soluble?Ions are the most soluble.All other non-charged atoms are the least soluble.119119Chemical BondingTwo Kinds2. Covalent Bonding - formed when two or more atoms share electrons

www.school-for-champions.com120Chemical BondingElements combine to make compoundsExample:O (oxygen) + 2H (two hydrogen) H2O (one water molecule) Covalent BondingNa (sodium) + Cl (chlorine) NaCl (salt) Ionic BondingEssential Question #101How do elements combine to produce compounds?Ionic bonding which involves gaining and losing electrons.Covalent bonding which involves sharing electrons.You are a carbon based life formThis means all of your cells contain carbon.The four types of molecules that make up your body contain carbon.These are sugars, lipids (fats), proteins, and nucleic acids.Essential Question #102Which element is found in all living or once living things?CarbonEssential Question #104In a chemical or physical change, how is a gas produced? Essential Question #105During a normal chemical reaction, what happens to matter? 126Chemical ReactionOccurs when the original substance(s) change form into new substance(s)Substances change due to changes in bonds or changes in bonds create new substancesSome clues to a chemical reaction may include bubbles, smoke, a strong smell, color change, temperature change, or a sizzling soundExample: two liquids mixed together create a gas.Changes in MatterPhysical ChangeChemical Change

In the physical change of vaporization, boiling and evaporation, gases are formed from liquids.

In a chemical change, a reaction can lead a set of reactants to form a gas as a product.

Essential Question #104In a chemical or physical change, how is a gas produced? Can both produce gas? Yes! A chemical reaction can produce a gas.Essential Question #105During a normal chemical reaction, what happens to matter? Reactants break or make bonds to form new products or substances.130Which is evidence that elements can combine to form new compounds?

Melting a solidFreezing a liquidMoving a piece of metal with a magnetPouring two liquids together to create a solid131Which is evidence that elements can combine to form new compounds?

Melting a solidFreezing a liquidMoving a piece of metal with a magnetPouring two liquids together to create a solidEssential Question #106In a chemical or physical change, how does mass change? During a chemical reaction, how does the total mass of the products compare to the total mass of the reactants? Essential Question #107134Law of Conservation of MassIn a chemical reaction, matter cannot be either created or destroyed but changes form.

Example: When wood is burned, it isnt destroyed but changed into ash, gases (smoke), water vapor (steam in the smoke), and energy (heat)All chemical equations have to show the same number of atoms on each side to show that no atoms are lost.135Chemical Reaction6CO2 + 6H2O C6H12O6 + 6O2reactantsproducts

C ___O ___H ___

C ___O ___H ___

6 18 12

6 18 12

In a physical change, mass does not change. No matter what physical changes occur, all atoms and molecules stay the same, therefore the mass stays the same.

Essential Question #106In a chemical or physical change, how does mass change?Mass is never lost or gained but changes form. During a chemical reaction, how does the total mass of the products compare to the total mass of the reactants?The mass of the products is equal to the mass of the reactants. Essential Question #107139139A chemical reaction produces two new substances, and each product has a total of 25 grams. What was the total mass of the reactants?

25 grams50 grams75 grams100 grams140A chemical reaction produces two new substances, and each product has a total of 25 grams. What was the total mass of the reactants?

25 grams50 grams75 grams100 grams141Chemical ReactionPhotosynthesis6CO2 + 6H2O C6H12O6 + 6O2reactantsproducts is a symbol that means yieldsCoefficient: number in front of a formula that multiplies all atoms in the formula to the rightSubscript: number that only multiplies the element to its leftYou start with carbon dioxide and water and end up with sugar and oxygenCount the number of carbon, hydrogen, and oxygen atoms on both sides. They must be equal according to the Law of Conservation of Mass.Coefficient Subscript142In the chemical formula for ammonia, NH3, what does the subscript 3 represent?

The number of nitrogen and hydrogen atoms in each molecule of ammonia.The number of hydrogen atoms in each molecule of ammonia.The number of ammonia molecules that will bond together.The number of nitrogen atoms in each molecule of ammonia.143In the chemical formula for ammonia, NH3, what does the subscript 3 represent?

The number of nitrogen and hydrogen atoms in each molecule of ammonia.The number of hydrogen atoms in each molecule of ammonia.The number of ammonia molecules that will bond together.The number of nitrogen atoms in each molecule of ammonia.Essential Question #108In a chemical or physical change, how does temperature change? Energy in Chemical ReactionsEndothermic reaction: a chemical reaction in which heat is taken in; any acid; base reaction takes in heat; the beaker feels cold after the reaction.Exothermic reaction: a chemical reaction in which heat is given off; fire is an exothermic reaction

Energy in Physical ChangesTemperature can change in physical changes also.When melting or vaporizing, molecules absorb heat. That is why these changes of state occur more when it is warm.When condensing or freezing, molecules give off heat. That is why you have to remove the heat to get materials to go through these changes of state.Essential Question #108In a chemical or physical change, how does temperature change?Both chemical and physical changes can cause temperature changes. Energy TransformationsEnergy can change formsLight can change into heat: sunlight feeling hotChemical energy can become mechanical energy: cells using sugar for energyChemical energy can become heat: wood burningHeat can be changed into mechanical energy: steam boatLight can be changed into chemical energy: photosynthesisElectricity can be changed into heat: ovenElectricity can be changed into mechanical energy: fan 148149149Which of the following could best be used to demonstrate energy being transformed from electricity to heat?

A magnifying glassA triple beam balanceA toasterA gas oven150Which of the following could best be used to demonstrate energy being transformed from electricity to heat?

A magnifying glassA triple beam balanceA toasterA gas oven151151A burning candle is in the process of transforming -

Heat energy into chemical energy.Chemical energy into light and heat.Chemical energy into mechanical energy.Chemical energy into nuclear energy.152A burning candle is in the process of transforming -

Heat energy into chemical energy.Chemical energy into light and heat.Chemical energy into mechanical energy.Chemical energy into nuclear energy.153153

www.livinglandscapes.bc.ca Chemical ReactionAcids and bases are chemically oppositeAcids contain many H+ and Bases contain many OH-NaOH + HCL NaCl + H2O sodium hydroxide hydrochloric acid salt waterBASE ACID NEUTRAL SUBSTANCES When a base is mixed with an acidic solution, neutralization occurs because the -

Base reaches absolute zeroAcid evaporatesBase chemically reacts with the acidMass of the solution increases155When a base is mixed with an acidic solution, neutralization occurs because the -

Base reaches absolute zeroAcid evaporatesBase chemically reacts with the acidMass of the solution increases156MixturesThe physical combination of 2 or more substancesCan be separated by physical meansA solution is a liquid mixtureExample: sand mixed with sugar can be separated by adding water, pouring off the liquid, evaporating the water so the sugar is left behind157MixturesHomogeneous mixture: a mixture that is evenly mixed; also called a solution; milk is homogenizedHeterogeneous mixture: a mixture that is unevenly mixed; soil is an example

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