Unit 2 ChemCom study guide: by 49ph3B28


									Unit 2 ChemCom study guide:

Review the Periodic Table: be able to recognize and explain Groups or Families, Periods, and
special areas such as alkali metals, alkaline earth metals, halogens, transition metals, noble gases,
lanthanides and actinides. Be able to explain and recognize examples of periodicity: the regular
repeating of patterns of properties. Know metals, non-metals and metalloids, know solids, liquids
and gases. Be able to interpolate atomic properties given properties of adjacent elements.
Remember the diatomic elements (H2,N2,O2,F2,Cl2,Br2, I2). Know Moseley vs. Mendeleev.

Recognize and explain physical vs. chemical properties and changes. Relate properties to
appropriate uses (such as for coins).

Write formulas for ionic compounds, designate charges of transition metals with Roman
numerals (Stock system), designate hydrates (•H2O) with the appropriate prefixes (mono, di, tri,
tetra, penta, hexa, hepta, octa, nona or deca for 1 through 10 units of water)

Recognize and write oxidations (loss of electrons) reductions (gain of electrons) – LEO goes
GER – and designate reducing or oxidizing agents. Be familiar with the activity series and the
meaning of the positions of different elements. Recall our lab on activity series of Mg, Zn, Cu
and Ag.

Balance chemical reactions, and translate word equations to balanced formula equations. Write
atom inventories (count types of atoms) of complex formulas in equations or stand-alone.
Recognize that the coefficients in a balanced equation represent the number of moles of the
substance reacting or being formed.

Explain a mole as a standard quantity of any material having Avogadro’s number (6.02 x 1023) of
particles (atoms, molecules, ions, formula units or any other grouping of materials). Draw an
analogy between the mole and other units such as the dozen. Identify molar mass as the mass in
grams equivalent to Avogadro’s number, and calculate molar mass in grams for any formula unit
based on the atomic mass of the atoms in grams (from the Periodic Table). Convert from number
of particles (count) to grams (mass). Calculate the percent by weight of an element in a formula.
Calculate relative moles of materials needed or made in a chemical reaction in moles or grams
(stoichiometry), be able to calculate percent yield.

Be able to explain the Law of Conservation of Matter, and relate it to practical issues such as
conservation/recycling; be able to explain that the issue in using up materials is the
contamination of pure substances with other materials such that they are difficult to reclaim.

Be able to exemplify and defend identification of materials as renewable or non-renewable.
Recognize the kinds of materials which come from the atmosphere, the lithosphere, and the

Be able to explain an alloy as a solid solution and recognize or provide examples of common
alloys. Have examples of the advantages of alloys over pure metals.

Be able to explain and exemplify allotropes as being multiple physical expressions of the same
element – same atoms, different bonding; different properties.

Review your definitions: chemical vs. physical change, molar mass, family vs. period, reduction
vs. oxidation, mole, allotrope, alloy

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