8th GRADE PHYSICAL SCIENCE: 2nd SEMESTER EXAM OUTLINE

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1 1) Light is an wave. Electromagnetic LIGHT 2) Draw, label, and give an example of each section of the electromagnetic spectrum. Radio - Radios Micro The appliance in your house Infra- Thermal Visible What we see Ultraviolet- Sunburn X-ray- The thing we use to see our bones Gamma Nuclear bomb 3) As wavelength decreases, frequency. increases 4) Reflection- The bouncing of light waves off of an object. 5) Refraction The bending of light waves as they travel from one medium into another. 6) Diffraction The scattering of light as it travels through an opening or around an object. 7) Lens a transparent object which light travels. 8) What is the difference between a convex and concave lens? Concave lens causes an object to look smaller. Convex lens causes and object to look larger. CHEMICAL & PHYSICAL PROPERTIES/CHANGES Give an example of each term below: 1) Physical property a property of matter which can be observed without changing the identity of the matter. (red color) 2) Chemical property a property of matter that describes a substance based on its ability to change into a new substance with different properties (flammable) 3) Physical change a change which affects one or more physical properties of a substance, but you are able to return the substance back to the original substance with the same properties (squeeze a balloon) (without popping it) 4) Chemical change a change that occurs when one or more substances are changed into entirely new substances with different properties. The substance cannot be changed back into the original substance (burn paper) THERMAL ENERGY 1) Temperature- The measure of the average kinetic energy of the particles in a substance a) relationship between temperature & how fast the particles of an object are moving The higher the temp. the faster the motion of the particles in an object (lower = slower) 2) thermal expansion The higher the temp. of an object the larger the volume (object will get larger) (cut sections found on a bridge) 3) Kelvin The official SI unit for temperature 5) absolute zero Theoretical temp. which all particle motion stops 0 o K 6) heat A process of transferring energy between objects at different temperatures. 7) thermal energy The total energy of the particles that make up a substance. a) What unit is thermal energy measured in? Joules 8) thermal equilibrium The point at which two objects reach the same temperature 9) conduction- The process of transferring thermal energy by direct contact. a) give an example- touch a hot pot 2) conductor A substance which conducts thermal energy easily

2 3) insulator A substance which does not conduct thermal energy easily 4) convection The transfer of thermal energy by the circulation of a liquid or gas a) give an example (lava lamp) 5) radiation The transfer of thermal energy through matter or space a) give an example (the sun s rays) 6) thermal conductivity The rate at which an object conducts thermal energy 7) specific heat capacity The amount of energy needed to change the temp of 1 kg of a substance by 1 o C 15) Use the table on page 256 to answer the following questions about specific heat: a) list the 3 substances that heat the fastest Lead Gold Mercury b) Does copper or aluminum heat the slowest? Al THE ATOM 1) atom The smallest particle into which an element can be divided and still be the same substance 2) Which takes up more space in an atom? (Nucleus or empty space) EMPTY SPACE 3) Define and give the charge for the following: a) Protons positively charged particle found in the nucleus b) Neutrons particle found in the nucleus which has NO charge c) Electrons negatively charged particle found outside of the nucleus 4) Quarks Subatomic particle which makes up protons and neutrons 5) Nucleus dense region at the center of the atom which contains protons and neutrons 6) electron energy levels The shells which Bohr states contains 2, 8, and 18 electrons a) maximum # of electrons on the first 3 energy levels (28) 1 st =2 2 nd =8 3 rd =18 b) draw a Bohr diagram for an atom that has 11 electrons c) List the valence electrons for the Bohr model you drew The third shell contains 1 electron 7) valence shell The outermost shell which does contain electrons 8) valence electrons The electrons which are located on the outermost shell 9) atomic number The number which signifies the number of protons in that element 10) mass number The mass of the average isotope of that element 11) isotope An element which does not contain the number of neutrons which it should normally 12) Find the following: a) mass number 11 b) protons 5 c) neutrons 6 (11-5=?) d) electrons (with the charge) 2 (5-3=?) B 5

3 ATOMIC SCIENTISTS Give one fact about each atomic scientist: 1) John Dalton The atom is a hard ball 2) JJ Thomson He designed the plum-pudding model (electrons are negative particles) 3) Ernest Rutherford He conducted the gold foil experiment (atom has mass) 4) Neils Bohr He designed a model where electons are found on shells outside the nucleus. This helped explain the reactivity of atoms (valence shell electrons). 5) Schrödinger & Heisenberg (Electron cloud) They designed the cloud theory (you cannot tell where an electron can be found). PERIODIC TABLE 1) The Periodic Law The chemical & physical properties of elements are based on their atomic # 2) Sections of the periodic table a)groups They are the vertical columns of elements i) name 1 element in group 16 Oxygen b) periods The horizontal rows of elements i) name 1 element in period 4 K potassium c) metals Found to the Left of the stair steps and are solid at room temp. and good conductors i) name 1 element that is a metal Fe iron d) nonmetals Found to the Right of the stair steps and most are gases at room temp. They are poor conductors and not shiny i) name 1 element that is a nonmetal C carbon e) metalloids Called semiconductors and found along the stair step. They have properties of both metals and non-metals i) name 1 element that is a metalloid B Boron 3) Use the periodic table on pages to complete the following: a) The name for Na is _Sodium. b) Mercury has an atomic mass of _ c) The chemical symbol for gold is _Au. 4) The current periodic table is arranged by Atomic number (# of protons) 5) Draw dot diagrams for elements 1 10 H He Li Be B C N O F Ne 6) What family is neon in? Give one fact about the family. Nobel Gas non-reactive 7) Name one element in the alkali metals. Potassium ELEMENTS, COMPOUND, & MIXTURES 1) Element a pure substance that cannot be separated / broken down into simpler substances by physical or chemical means a) give an example Oxygen 2) compound a pure substance composed of two or more elements that are chemically combined and cannot be separated by physical means a) give an example NaCl 3) mixture A combination of two or more substances that are NOT chemically combined a) give an example PIZZA 4) How are elements and compounds similar?

4 Elements and compounds, each, have their own physical properties (boiling point, color) 5) How are compounds and mixtures similar? They are made of two or more substances CHEMICAL BONDS & COMPOUNDS 1) Atoms bond by,, or electrons. Loose, Gain, or Share (ionic or covalent) 2) ionic bond The force of attraction between oppositely charged ions 3) ions Charged particles that form during chemical reactions when they lose or gain valence elections 4) covalent bond The force of attraction between the nuclei of atoms and the valence electrons they SHARE 5) molecule A neutral group of atoms which are held together by covalent bonds (share) 6) binary compounds a combination of 2 elements a) give one example of using the criss-cross method to make a binary formula Mg +2 Cl -1 MgCl 2 CHEMICAL REACTIONS & EQUATIONS 1) How many atoms of each element are in the following chemical formula? 2H 2 SO 4 H = 4 S=2 O=8 2) Is the following equation balanced or unbalanced? (show your work) 2KCl + 3O 2 2KClO 3 K 2 2 Cl 2 2 O 6 6 Balanced list the number of atoms for each element in the above equation b ) label the following: i) Subscript - the 2 in the gas O 2 ii) Coefficient the 3 in the compound 3H 2 O iii) Reactants The LEFT side of the equation iv) Products The RIGHT side of the equation 3) Law of Conservation of Mass In a chemical reaction, there is no mass ever lost or gained a) How does a balanced equation illustrate this law? There is always the same number of atoms, of each element, on the reactant and product side of the equation TYPES OF REACTIONS 1) synthesis a reaction in which two or more substances combine to form a single compound 2) Decomposition a reaction in which a single compound breaks down to form two or more simpler substances 3) single replacement a reaction in which an element takes the place another element that is part of a compound 4) double replacement a reaction in which ions in two compounds switch places 5) endothermic a chemical reaction in which energy is absorbed 6) exothermic a chemical reaction in which energy is released or removed 7) List the 4 clues that a chemical reaction is taking place. (choose 4 from the list below) * change in color * new odor produced * release of thermal energy * absorption of thermal energy (exothermic or endothermic) * Fizzing or Foaming * production of sound * production of Light

5 ACIDS & BASES 1) Acid (ph 0-6.9) any compound that increases the number of hydrogen ions when dissolved in H 2 O Example (HCl = stomach acid) or (saliva) Bases ) Base (ph ) any substance that increases the number of hydroxide ions when dissolved in H 2 O a) Example (shampoo) (bleach) 3) neutralization A chemical reaction between an acid and a base (bringing a solution closer to 7) 4) indicator An organic compound that changes color in an acid or base a) give an example of one indicator and how it indicates an acid or base (red cabbage juice turns litmus paper pink or red if an acid) 5) ph scale a scale that ranges from 0 to 14 to describe the ph of a substance a) draw and label (3 acids / 3 bases) Acids Stomach acid = 1 Lemon juice = 3 Coffee = 5 Bases Baking Soda = 9 Bleach = 12 Oven Cleaner = 13 Acids Neutral 7