CHEM 121: Exam 1 Study Guide. Chapter 1. • Know the Scientific method. •
Know the definitions for hypothesis, scientific law, and scientific theory. Chapter 2
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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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