MIDTERM REVIEW WORKSHEET OPEN BOOK 30 POINT QUIZ To Be Turned in at your Midterm Components of an Experiment Independent Variable: The factor in the experiment that is purposely changed. “I” the examiner change Dependent Variable: Measurable factor that responds to a change in the independent variable. Dependent depends on the independent. Constant- Conditions that remain the same during the course of the experiment Control- A standard for comparison, not in every experiment. **Remember how to choose the Independent variable (what “I” the examiner change), Dependent variable (depends on the independent- usually measurable), Constants (remains the same), Control (standard to compare to) etc. How to Graph “Effect of IV on DV” Scientific Method • A series of logical steps that are followed to solve a problem. • Uses critical thinking PIE CHART- parts of a whole, % Bar Graph- Comparison of similar data for several different items or events LINE GRAPH: For displaying data that changes over time Metric Conversion of Units Base: Meter Liter Gram by Metric Conversion Units Accuracy vs Precision MATTER Substance Element Compound Mixture Heterogeneous Mixture Homogeneous Mixture ‘Solutions’ Atom: Molecule: Examples: Examples: Examples: Examples: MATTER PURE SUBSTANCE • Matter that has a fixed composition (makeup) and definite properties (chemical and physical). • Are chemically combined- so they can’t be physically separated. MIXTURE • Matter that is a combination of two or more pure substances that do not have a fixed composition or definite properties. • Are NOT chemically combined, so components CAN be separated. Compound: A substance made of atoms of 2 or more different elements that are chemically combined. Element: A substance that can’t be broken down into simpler substances Each element is made of only one kind of atom. ATOM: The smallest unit of an element that maintains the properties of the element. MOLECULE: H2O O2 The smallest unit of a substance that behaves like the substance. (Keeps all of its physical and chemical properties) Changes of State PHYSICAL CHANGE A change of matter from one form to another without a change in chemical properties • • • • • • Dissolving Sanding Crushing Breaking/cutting Bending/twisting Mixing • CHANGE OF STATE – Melting/evaporating – freezing CHEMICAL CHANGE A change of matter that occurs when a substance changes composition by forming one or more new substances • • • • • • • ODOR COLOR CHANGE BUBBLING FIZZING FOAMING HEAT PRODUCED SOUND PRODUCED CANNOT BE REVERSED BY PHYSICAL CHANGES Changes of State Buoyant Force The buoyant force is equal to the weight of the liquid displaced. Archimedes Principle An object that is submerged in a fluid is buoyed up by a force equal to the weight of the fluid that is displaced Density D = M/V mass volume Pascal’s Principle A change in pressure at any point in an enclosed fluid at rest is transmitted equally throughout the fluid. V I S C O S I T Y Pressure Temperature and Volume Boyle’s Law, Charle’s Law of Gases: Constant Temperature: If you decrease the volume you will increase the pressure. Constant Pressure: If you increase the temperature the volume will increase (if it could). Bohr’s Model of the Atom Like planets around the sun Periodic Table METALS NONMETALS METALS •Alkali Metals •Alkali Earth Metals •Transitions Metals •‘Other Metals’ Form Cations + NON-METALS •‘Other Non-Metals’ •Halogens •Noble Gases Form Anions - ATOMIC NUMBER = Number of Protons = Number of Electrons MASS NUMBER = (Atomic Mass, Atomic Weight) Number of Protons + Number of Neutrons Atomic Number + Number of Neutrons Using the Periodic Table ELEMENT NAME AND SYMBOL ATOMIC # (P) MASS NUMBER (round to nearest whole number) NUMBER of PROTONS NUMBER of NEUTRONS NUMBER of ELECTRONS 15 38 Gallium (Ga) 31 NUMBER OXIDATION of NUMBER VALENCE and ELECTRONS CHARGE (+ or -) Using the Periodic Table ELEMENT NAME AND SYMBOL ATOMIC # MASS NUMBER (round to nearest whole number) NUMBER of PROTONS NUMBER of NEUTRONS NUMBER of ELECTRONS 31 70 31 39 31 NUMBER OXIDATION of NUMBER VALENCE and ELECTRONS CHARGE (+ or -) Phosphorus (P) Strontium (Sr) Gallium (Ga) 3 +3 Remember: Atomic number is = the number of Protons In a Neutral Atom the number of = protons is = to the number of – electrons All the Mass in in the nucleus- The Mass Number is = Protons + Neutrons Valence Electrons = outer shell = Group 1 has 1, Group 2 = 2, Group 13 = 3, Group 14 = 4 etc Oxidation # = # of electrons taken in (-) or give away (+) to get to a full valence shell. Dalton's Atomic Theory • 1) All matter is made of atoms. Atoms are indivisible and indestructible. • 2) All atoms of a given element are identical in mass and properties • 3) Compounds are formed by a combination of two or more different kinds of atoms. • 4) A chemical reaction is a rearrangement of atoms. This chart and a Periodic Table will be provided to youyou just have to know how to READ it and USE it. Practice with your class worksheets, quizzes and homeworks Organic Compound A COVALENTLY bonded compound that contains carbon Most common elements: C,H ANY organic compound that is burned will release Carbon in some form Hydrocarbon An organic compound made of only carbon and hydrogen Simplest Hydrocarbon: Methane Alkanes, Alkenes, Alkynes Only Single Bonds C-C At least one Double C=C At least one Triple C=C POLYMERS Polymers are substances that are made up of a large number of repeating units (monomers). There are both synthetic and naturally occurring polymers. Formed by chemical reactions in which these monomers are joined in a certain order, forming a chain. Natural Polymers: Proteins - silk, collagen, keratin, DNA Repeating units of amino acids Carbohydrates - cellulose, starch. Made up of repeating units of glucose Other Natural polymers: Rubber (hydrocarbon base) and silicones (alternating silicon and oxygen). Cross Linking of Polymers: Cross linking: Makes the polymer elastic, flexible by helping it to go back to its original shape after stretching. Too many cross links and the polmer becomes rigid (like the back of a desk chair), or may even crack/break Counting Atoms 2H2O = 2 Molecules of H2O, or 4 atoms of H, 2 atoms of O, 6 atoms all together Co