CHEM 121: Exam 1 Study Guide Chapter 1 • Know the Scientific method • Know the definitions for hypothesis, scientific law, and scientific theory, and be able to explain the differences between them. Chapter 2 • Length, mass, weight, volume - Know 1 ft.≡12 in., 1 yd. ≡3 ft., 1 gal≡4 qt., 1 qt.≡2 pints, 1 pint≡2 cups -­‐ Know 1 cm3≡1 mL and 1 dm3≡1 L • Significant figures or digits -­‐ Rounding -­‐ In addition, subtraction -­‐ In multiplication, division -­‐ In measurements (uncertainty) • Scientific notation • Solve problems using dimensional analysis with conversion factors, showing all work • Use dimensional analysis to solve problems • Metric system -­‐ Know these metric prefixes and their symbols: kilo (k), deci (d), centi (c), milli (m), and micro (µ and mc) -­‐ Know mcg=micrograms in medicine -­‐ Be able to perform metric-­‐metric conversions using these prefixes Chapter 3 • Know that matter is studied at the macroscopic, microscopic, particulate (molecular) levels • Physical states of matter -­‐ Determine physical state of substances (solids, liquids, gases) given descriptions of volume, shape, particles moving, etc. • Use the metric-­‐English conversions provided (1 in. ≡2.54 cm; 1 lb=453.6 g; 1 qt=946 mL) • Volume by calculation -­‐ Vrectangular solid = length × width × thickness • Volume by displacement m
V
-­‐ Be able to determine density, mass, or volume given the other two quantities -­‐ Identify what items sink or float in a given liquid given the densities of the liquid and other substances. • Density: d =
• Temperature - Know the formulas for converting ˚F-­‐to-­‐˚C or ˚C-­‐
to-­‐˚F and K-­‐to-­‐˚C or ˚C-­‐to-­‐K • Percentage: ratio of parts per 100 parts -­‐ Given amount of part and whole, calculate % -­‐ Use a given % to solve for part or whole • Classification of matter – Given examples, determine which are elements, compounds, or mixtures – Given molecular-­‐level images, determine which are elements, compounds, or mixtures and solids, liquids, or gases – Distinguish between homogeneous and heterogeneous mixtures Chapter 3 (Continued) • Be able to identify properties and changes as physical or chemical -­‐ Know terms for changes of state: -­‐ Melting, freezing, vaporizing, condensation, sublimation, deposition • Chemical reaction: -­‐ reactants: starting materials -­‐ products: substances produced in reaction kinetic energy (KE): energy associated with an object’s motion -­‐ Faster objects have higher KE. • Law of Conservation of Mass -­‐ Matter is neither created nor destroyed in a chemical reaction. -­‐ Solve problems conserving mass. • Law of Conservation of Energy -­‐ Know 6 forms of energy: heat, light, chemical, electrical, mechanical, and nuclear joule (J): SI unit of energy; 1 kJ=1000 J and 1 watt = 1 J/s calorie (cal): energy needed to raise the temperature of 1 g of water by 1˚C potential energy (PE): energy due to its position or composition (chemical bonds) Be able to carry out calculations involving energy in J, cal, Cal, and kilowatt-­‐hours (kWh). heat: energy is transferred from a hotter substance to a cooler substance – Identify what lost heat and gained heat given different scenarios. Know the relative kinetic energy of solids, liquids, and gases Endothermic versus Exothermic changes: – endothermic: a change requiring energy – exothermic: a change that releases energy – To determine for physical changes consider if the reactants have more or less kinetic energy than the products. – To determine for chemical changes consider if the surrounding became hotter or colder after the reaction. heat capacity (in J/mol⋅˚C): the amount of heat capacity necessary to raise the temperature of a given amount of substance by 1˚C specific heat (in J/g⋅˚C): the amount of heat to raise temperature of 1 gram of a substance by 1˚C. • Recognize that the greater the heat capacity or specific heat of a substance, the more heat energy it can absorb before its temperature begins to rise. Chapter 4 • Know ideas of matter proposed by Democritus, Empedocles, and Aristotle. • Know the main points of John Dalton’s Model, what was later proven wrong and why. • Know people and discoveries associated with the discovery of protons, neutrons, electrons. • Know Plum-­‐Pudding Model versus Nuclear Model. CHEM121 Exam 1 Study Guide F2016
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Chapter 4 (Continued) • Know Rutherford’s Alpha-­‐Scattering Experiment and what was determined from it (atomic nucleus, atom mostly empty space, the size of an atom relative to its nucleus). • Subatomic particles – proton (p+): +1 charge, inside nucleus – neutron (n): neutral, inside nucleus – electron (e–): –1 charge, outside nucleus • Use the Periodic Table to identify those elements whose naturally occurring isotopes are all radioactive and unstable. • Electrostatic force: force resulting from a charge on particles -­‐ Objects w/ like charges repel one another. -­‐ Objects w/ unlike charges attract each other. • Know the names and element symbols for elements #1-­‐20 on the Periodic Table. – Given the element symbol, name the element, or vice versa. Spelling counts! • Know definitions of isotope, atomic mass • Atomic notation: mass number = A
atomic number = Z E = element symbol
mass # (A): # of protons + # of neutrons atomic # (Z): # of protons=# of electrons • Determine # of protons, neutrons, and electrons for any given isotope. • Give atomic notation for any element given element name/symbol and mass number • Use the Periodic Table to identify the most abundant isotope of any element given its naturally occurring isotopes. The Periodic Table column = group, family row = period, series Representative Elements: A Group Elements Group IA: alkali metals (except H) Group IIA: alkaline earth metals Group VIIA: halogens Group VIIIA: noble gases Transition Metals/Elements: B Group Elements Inner Transition Elements: -­‐ Elements in lanthanide and actinide series • Metals, nonmetals, and semimetals: -­‐ Know properties of metals and nonmetals -­‐ Location on Periodic Table and properties • Know which elements exist as solids, liquids, gases at room temperature (25˚C) • Know the names and symbols for all elements included on p. 10 in the Ch. 4 lecture notes, Ti (titanium), and Sr (strontium), and uranium (U). Spelling counts! You will be given a Periodic Table with elements symbols, atomic numbers, and atomic masses. Be able to solve problems combining concepts covered in Chapters 1-­‐4. CHEM121 Exam 1 Study Guide F2016
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