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Wake County 8th Grade Science Curriculum
End of Year Review Scientific Method and Properties of Matter and Chemistry Wake County 8th Grade Science Curriculum
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How do I set up an experiment?
Essential Question #79 How do I set up an experiment?
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Lab Safety What are the potential hazards? Broken glass Spills Fire
Electrical shocks Can you think of other hazards?
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Essential Question #80 How do I safely manipulate materials and equipment?
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Lab Safety How do I safely manipulate materials and equipment and conduct appropriate procedures? Follow safety rules covered at the beginning of the year. Know these rules! Follow teacher instructions. What else applies?
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Essential Question #80 How do I safely manipulate materials and equipment? Know all the safety rules of the safety contract and classroom.
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How do I conduct appropriate procedures?
Essential Question #81 How do I conduct appropriate procedures?
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Scientific Method Ask 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
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Essential Question #81 How do I conduct appropriate procedures?
Know and use the Scientific Method.
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Essential Question What types of questions can be answered through scientific investigation?
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Scientific Method 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? What types of questions can be answered through scientific investigations? How do I set up an experiment?
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Essential Question #82 What types of questions can be answered through scientific investigation? Questions must be testable and measurable. No opinion can be used as data.
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Analyzing Data How do you analyze large amounts of data? Line Graph
Bar Graph Pie Chart Can you think of other ways to analyze data?
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What are dependent and independent variables and how are they related?
Essential Question #83 What are dependent and independent variables and how are they related?
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Analyzing Data Independent variable is the variable being tested. Can be changed to get different observations. Always the X axis Dependent variable results depend on the independent variable. Changes based on changes in the independent variable. Always the Y axis. What are dependent and independent variables and how are they related? Dependent variable Independent variable
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What are dependent and independent variables and how are they related?
Essential Question #83 What are dependent and independent variables and how are they related? Can you explain?
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Essential Question #84 Why do I need a control?
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Scientific Method Why 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 Why do I need to have a control?
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Essential Question #84 Why do I need a control?
You need to know what the results would be without the variable being tested.
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How many variables do I manipulate or change?
Essential Question #85 How many variables do I manipulate or change?
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Always Experimentation How many variables do I manipulate (or change)?
Only ONE
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Essential Question #85 How many variables do I manipulate or change?
Just one or you don’t know which one provided the measurable data.
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How do I set up an experiment?
Essential Question #79 How do I set up an experiment? Class discussion
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Properties of Matter Matter Mass Volume Has mass and volume
Amount of matter contained in a substance Measured in grams (g) Volume Amount of space an object occupies Measured in liters (L)
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Changes in Matter Physical Change Chemical Change
A change in a substance that doesn’t change it’s identity Example: Ice melting or chopping wood Chemical Change A change in which one or more substances combine or break apart to form new substances Example: burning paper or putting an acid in a base
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How is density used to compare different substances?
Essential Question #86 How is density used to compare different substances?
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Properties of Matter Density > 1 (sinks) Density < 1 (floats)
Density is the quantity of matter that is packed into a fixed space. D = m/v (OR) gram/liter Density = Mass/Volume Density > 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 How is density used to compare different substances?
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How is density used to compare different substances?
Essential Question #86 How 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.
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Essential Question #87 How are boiling points and melting points used to compare different substances?
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Properties of Matter In matter, how does temperature change?
All atoms and molecules move. The faster they move, the higher the temperature Change in temperature occurs by speeding up or slowing down particle movement
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States of Matter Gases Occur when particles move freely (are fluid)
Volume changes by being easily compressed or expanded A 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) Gases
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States of Matter Liquids
Occur when particles move freely (fluid) but are bonded to each other. Volume is constant but shape changes Movement 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) Liquids
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States of Matter Solids Occur when particles vibrate in place
Have a definite shape and volume Different substances have different freezing points. Water becomes solid at 0C if heat is taken away. This is freezing. Iron becomes solid at 1538°C if heat is taken away. This is also freezing. Solids
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Of the states of matter, gas is the only state that
Is fluid Has mass Is highly compressible Has a definite shape
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Of the states of matter, gas is the only state that
Is fluid Has mass Is highly compressible Has a definite shape
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States of Matter Terms to Remember
Liquid is changed into a vapor. Liquid is changed into a vapor by adding heat Gas cooling and becoming liquid Liquid cooling and becoming a solid Solid turning directly into a gas without becoming liquid (example: dry ice) Evaporation Boiling Condensation Freezing Sublimation
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Properties of Matter How 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
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Essential Question #87 How 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.
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Essential Question (#77)
How does water hold heat? (We already answered, but lets review again)
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Properties of Matter Specific Heat
The amount of energy needed to raise one gram of a substance by one degree Celsius Water has a very high specific heat This means it can absorb a lot of heat That is why water works well to put out a fire Specific Heat
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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.
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Which of the following has the least effect on lake water temperature?
The depth of the water The angle of incoming sun rays The number of fish in the lake The lake’s surface area
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Which of the following has the least effect on lake water temperature?
The depth of the water The angle of incoming sun rays The number of fish in the lake The lake’s surface area
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How is solubility used to compare different substances?
Essential Question #88 How is solubility used to compare different substances?
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Properties of Matter What is a solution? A mixture formed when one substance dissolves another. What is a solvent? A substance that dissolves another substance What 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 hold
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Properties of Matter How 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
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How is solubility used to compare different substances?
Essential Question #88 How 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.
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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).
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Properties of Matter Chromatography
: a means of separating a mixture based on polarity and solubility upload.wikimedia.org Chromatography of chlorophyll Chromatography of inks
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How is malleability used to compare different substances?
Essential Question #89 How is malleability used to compare different substances?
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Which material is the most/least malleable?
Essential Question #90 Which material is the most/least malleable?
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Properties of Matter How 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?
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How is malleability used to compare different substances?
Essential Question #89 How 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.
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Which material is the most/least malleable?
Essential Question #90 Which material is the most/least malleable? Metals are the most malleable Nonmetals are the least malleable.
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How is ductility used to compare different substances?
Essential Question #91 How is ductility used to compare different substances?
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Properties of Matter Ductility - 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?
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How is ductility used to compare different substances?
Essential Question #91 How is ductility used to compare different substances? Ductility - the ability to be stretched into a thin wire Some substances are more ductile than others.
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Chemistry 57
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What is the structure of an atom?
Essential Question #92 What is the structure of an atom?
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Chemistry Atom: the smallest unit of matter that retains the identity of the substance Three particles: Protons Neutrons Electrons Nucleus 59 alternativealtruist.wordpress.com
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Chemistry Structure of an Atom
Nucleus: contains protons and neutrons; the total number of particles in the nucleus is the atomic mass number Proton: 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 atom 60
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Chemistry Structure of an Atom
The structure of an hydrogen atom, helium atom, lithium atom and a sodium atom 61
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Chemistry Structure of an Atom
Electron: subatomic particle with a negative charge and located outside the nucleus commons.wikimedia.org commons.wikimedia.org en.wikipedia.org 62
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Structure of an Atom Where do you find the number of particles of atoms in a periodic table? kaffee.50webs.com 63
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Chemistry Structure of an Atom
Atomic Number The number of protons in the nucleus of an atom This number identifies the atom Increases as you go to the right in periods and starts again on the left of the next period Atomic Number = Protons 64
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mass number = protons + neutrons
Chemistry Structure of an Atom Atomic Mass Number: the number of protons and neutrons in the nucleus of an atom As the atomic number increases, usually, so does the mass As the atomic number increases, usually, so does the density mass number = protons + neutrons The number of neutrons depends on which isotope of the element you are using. Atomic Mass Numbers H H H-3 for the isotopes of hydrogen 65
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Chemistry Structure of an Atom
Atomic Mass: the average mass number of all isotopes of an atom. Round this number to find the mass number of the atom. en.wikiversity.org education.jlab.org 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. → 66
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Chemistry Structure of an Atom
To find the numbers of the different particles of an element: Atomic Number = Protons atomic number 6 = 6 protons Electrons = Protons 6 electrons = 6 protons Atomic Mass – Protons = Neutrons atomic mass (rounded) 12 – 6 protons = 6 neutrons iss.cet.edu 67
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Essential Question #92 Protons (+) and Neutrons (o) inside nucleus
What is the structure of an atom? Protons (+) and Neutrons (o) inside nucleus Electrons (-) surrounding the nucleus
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Atomic mass of the element carbon Atomic number of the element carbon
Looking at the block of the element Carbon on the periodic table, the number 6 represents? Atomic mass of the element carbon Atomic number of the element carbon Number of neutrons in the element carbon Number of valence electrons in the element carbon 69
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Atomic mass of the element carbon Atomic number of the element carbon
Looking at the block of the element Carbon on the periodic table, the number 6 represents? Atomic mass of the element carbon Atomic number of the element carbon Number of neutrons in the element carbon Number of valence electrons in the element carbon 70
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Essential Question #93 What are chemicals?
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Chemistry What is a chemical? Chemical: any substance made of atoms
Element: a substance that cannot be broken down into simpler substances by ordinary chemicals means Periodic Table: an arrangement of elements in order of increasing atomic numbers that demonstrates the periodic patterns that occur among the elements 72
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Essential Question #93 What are chemicals?
Anything that is made of atoms. You are made of chemicals.
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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 compound A mixture An element An acid
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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 compound A mixture An element An acid
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How are the elements categorized in the periodic table?
Essential Question #94 How are the elements categorized in the periodic table?
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Essential Question #95 What happens to the number of protons as you move to the right on a periodic table?
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Which material is the most/least dense?
Essential Question #96 Which material is the most/least dense?
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Atomic Number = Number of Protons
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.
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80 facstaff.gpc.edu
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Essential Question #95 What 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.
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Which material is the most/least dense?
Essential Question #96 Which 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.
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Structure of the Periodic Table
Period: 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 group or family → period→ energy.com 83
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Essential Question #97 How does the periodic table help you to identify the properties of the elements?
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Alkali Metals First column in the periodic table
First column in the periodic table They have one electron in the outer shell This characteristic makes them the most reactive metals 85
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Alkaline Earth Metals Second column in the periodic table
Alkaline Earth Metals Second column in the periodic table Have two electrons in the outer shell Second most reactive metals in the periodic table 86
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Which materials provide the best/worst electrical conductivity?
Essential Question #98 Which materials provide the best/worst electrical conductivity?
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Which material is the most/least magnetic?
Essential Question #99 Which material is the most/least magnetic?
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Metals An element below and to the left of the stair-step line of metalloids About 80% of the known elements are metals Most are shiny and conduct heat and electricity Malleable Low specific heat (absorbs heat quickly) Many metals demonstrate magnetism Are pink in the chart 89 media-2.web.britannica.com
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A 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. 90
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A 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. 91
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Metals have low specific heats and high melting points.
Which 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. 92
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Metals have low specific heats and high melting points.
Which 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. 93
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Electrical conductivity
Which property of metals allows them to be used to make coins that have the same thickness? Electrical conductivity Density Malleability Specific heat 94
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Electrical conductivity
Which property of metals allows them to be used to make coins that have the same thickness? Electrical conductivity Density Malleability Specific heat 95
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Metalloids An element with properties of both metals and nonmetals located along the stair-step line on the right side of the periodic table Most of the elements touching the stair-step line Green in the chart 96 96 96 media-2.web.britannica.com
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Nonmetals An element above and to the right of the stair-step line of metalloids Dull Non-conductive of heat or electricity so they make good insulators Non malleable Blue in the chart Non magnetic 97 97 media-2.web.britannica.com
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Essential Question #98 Which materials provide the best/worst electrical conductivity? Metals are the best conductors Nonmetals are the worst conductors
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Which material is the most/least magnetic?
Essential Question #99 Which material is the most/least magnetic? Metals are the most magnetic Nonmetals are the least magnetic.
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Insulation materials reduce heat loss because they -
Are poor conductors Block out the sun Reduce evaporation Promote convection 100 100
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Insulation materials reduce heat loss because they -
Are poor conductors Block out the sun Reduce evaporation Promote convection 101
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Halogens Seventeenth column in the periodic table (next to last)
Needs one electron to fill the outer shell Most reactive nonmetals in the periodic table 102
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Noble Gases Full outer shells The least reactive of all elements
Eighteenth column (last group) 103
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Essential Question #97 How 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.
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Essential Question #94 How are the elements categorized in the periodic table? Groups or families and periods Metals, nonmetals, and metalloids Alkali metals Alkaline earth metals Transition metals Halogens Nobel gases
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In a chemical or physical change, how does volume change?
Essential Question #100 In a chemical or physical change, how does volume change?
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Changes in Matter Chemical Change Physical Change
A change in a substance that doesn’t change it’s identity Example: Ice melting or chopping wood Chemical Change A change in which one or more substances combine or break apart to form new substances Example: burning paper or putting an acid in a base Bonds are broken and/or made in a chemical change (reaction) 107
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Changes in Matter Chemical Change Physical 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. Chemical Change
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In a chemical or physical change, how does volume change?
Essential Question #100 In a chemical or physical change, how does volume change? Class discussion
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There is a change in the mass of the can.
Which 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. 110 110
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There is a change in the mass of the can.
Which 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. 111
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Which process is a physical change?
Rusting iron Burning coal Tarnishing silver Melting ice 112 112
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Which process is a physical change?
Rusting iron Burning coal Tarnishing silver Melting ice 113
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How do elements combine to produce compounds?
Essential Question #101 How do elements combine to produce compounds?
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Which element is found in all living or once living things?
Essential Question #102 Which element is found in all living or once living things?
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Which materials are the most/least soluble?
ESSENTIAL QUESTION #103 Which materials are the most/least soluble?
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Chemical Bonding ffdgfg Two Kinds
1. Ionic Bonding - formed when two or more atoms gain or lose electrons and then become charged Since ions are charged particles, they are also easily dissolved in water ffdgfg 117
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ESSENTIAL QUESTION #103 Which materials are the most/least soluble? Ions are the most soluble. All other non-charged atoms are the least soluble.
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Chemical Bonding Two Kinds
2. Covalent Bonding - formed when two or more atoms share electrons 119 119
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Chemical Bonding Elements combine to make compounds Example:
O (oxygen) + 2H (two hydrogen) H2O (one water molecule) Covalent Bonding Na (sodium) + Cl (chlorine) NaCl (salt) Ionic Bonding 120
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Essential Question #101 How do elements combine to produce compounds? Ionic bonding which involves gaining and losing electrons. Covalent bonding which involves sharing electrons.
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You are a carbon based life form
This 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.
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Which element is found in all living or once living things?
Essential Question #102 Which element is found in all living or once living things? Carbon
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In a chemical or physical change, how is a gas produced?
Essential Question #104 In a chemical or physical change, how is a gas produced?
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During a normal chemical reaction, what happens to matter?
Essential Question #105 During a normal chemical reaction, what happens to matter?
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Chemical Reaction Occurs when the original substance(s) change form into new substance(s) Substances change due to changes in bonds or changes in bonds create new substances Some clues to a chemical reaction may include bubbles, smoke, a strong smell, color change, temperature change, or a sizzling sound Example: two liquids mixed together create a gas. 126
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Changes in Matter Chemical Change Physical 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. Chemical Change
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Essential Question #104 Can both produce gas?
In a chemical or physical change, how is a gas produced? Can both produce gas? Yes! A chemical reaction can produce a gas.
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Essential Question #105 During a normal chemical reaction, what happens to matter? Reactants break or make bonds to form new products or substances.
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Which is evidence that elements can combine to form new compounds?
Melting a solid Freezing a liquid Moving a piece of metal with a magnet Pouring two liquids together to create a solid 130
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Which is evidence that elements can combine to form new compounds?
Melting a solid Freezing a liquid Moving a piece of metal with a magnet Pouring two liquids together to create a solid 131
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In a chemical or physical change, how does mass change?
Essential Question #106 In a chemical or physical change, how does mass change?
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Essential Question #107 During a chemical reaction, how does the total mass of the products compare to the total mass of the reactants?
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Law of Conservation of Mass
In a chemical reaction, matter cannot be either created or destroyed but changes form. Example: When wood is burned, it isn’t 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. 134
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Chemical Reaction 6CO2 + 6H2O C6H12O6 + 6O2 C ___ O ___ H ___ 6 18
reactants products C ___ O ___ H ___ 6 18 12 C ___ O ___ H ___ 6 18 12 135
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In a physical change, mass does not change
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.
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Essential Question #106 In a chemical or physical change, how does mass change? Mass is never lost or gained but changes form.
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The mass of the products is equal to the mass of the reactants.
Essential Question #107 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.
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A chemical reaction produces two new substances, and each product has a total of 25 grams. What was the total mass of the reactants? 25 grams 50 grams 75 grams 100 grams 139 139
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A chemical reaction produces two new substances, and each product has a total of 25 grams. What was the total mass of the reactants? 25 grams 50 grams 75 grams 100 grams 140
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is a symbol that means “yields”
Chemical Reaction Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 reactants products is a symbol that means “yields” Coefficient: number in front of a formula that multiplies all atoms in the formula to the right Subscript: number that only multiplies the element to its left You start with carbon dioxide and water and end up with sugar and oxygen Count the number of carbon, hydrogen, and oxygen atoms on both sides. They must be equal according to the Law of Conservation of Mass. Coefficient Subscript 141
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The number of nitrogen and hydrogen atoms in each molecule of ammonia.
In 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. 142
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The number of nitrogen and hydrogen atoms in each molecule of ammonia.
In 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. 143
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In a chemical or physical change, how does temperature change?
Essential Question #108 In a chemical or physical change, how does temperature change?
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Energy in Chemical Reactions
Endothermic 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
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Energy in Physical Changes
Temperature 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.
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Essential Question #108 In a chemical or physical change, how does temperature change? Both chemical and physical changes can cause temperature changes.
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Energy Transformations
Energy can change forms Light can change into heat: sunlight feeling hot Chemical energy can become mechanical energy: cells using sugar for energy Chemical energy can become heat: wood burning Heat can be changed into mechanical energy: steam boat Light can be changed into chemical energy: photosynthesis Electricity can be changed into heat: oven Electricity can be changed into mechanical energy: fan 148
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Which of the following could best be used to demonstrate energy being transformed from electricity to heat? A magnifying glass A triple beam balance A toaster A gas oven 149 149
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Which of the following could best be used to demonstrate energy being transformed from electricity to heat? A magnifying glass A triple beam balance A toaster A gas oven 150
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A 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. 151 151
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A 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. 152
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Chemical Reaction Acids and bases are chemically opposite
Acids contain many H+ and Bases contain many OH- BASE ACID NEUTRAL SUBSTANCES NaOH + HCL →NaCl + H2O sodium hydroxide hydrochloric acid salt water 153 153
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Base reaches absolute zero Acid evaporates
When a base is mixed with an acidic solution, neutralization occurs because the - Base reaches absolute zero Acid evaporates Base chemically reacts with the acid Mass of the solution increases
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Base reaches absolute zero Acid evaporates
When a base is mixed with an acidic solution, neutralization occurs because the - Base reaches absolute zero Acid evaporates Base chemically reacts with the acid Mass of the solution increases 155
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Mixtures The physical combination of 2 or more substances
Can be separated by physical means A solution is a liquid mixture Example: sand mixed with sugar can be separated by adding water, pouring off the liquid, evaporating the water so the sugar is left behind 156
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Mixtures Homogeneous mixture: a mixture that is evenly mixed; also called a solution; milk is homogenized Heterogeneous mixture: a mixture that is unevenly mixed; soil is an example gallonchallenge.org nesoil.com 157
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