CHEM 121 Module 2 Practice Exam – 2 Versions with Answers & Rationales

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chem 121 exam 2 NEWEST 2026 ACTUAL EXAM TEST- COMPLETE REAL EXAM
QUESTIONS AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) ALREADY
GRADED A+ (MOST RECENT!!)




molecular mass - CORRECT ANSWER the sum of atomic masses of all
the atoms in a molecule of the substance


QUESTION : formula mass - CORRECT ANSWER the sum of atomic
masses of all the atoms in a formula unit of the compound, whether molecular
or not.


QUESTION : mole - CORRECT ANSWER the quantity of a given amount
of substance that contains as many molecules or formula units as the number of
atoms in exactly 12 g of carbon-12


QUESTION : avogadros number - CORRECT ANSWER the number of
atoms in one mol- 6.022 x 10^23


QUESTION : molar mass - CORRECT ANSWER the mass of one mole of
substance


QUESTION : percent composition - CORRECT ANSWER the mass
percentage of each element in the compound




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QUESTION : empirical formula - CORRECT ANSWER the formula of a
substance written with the smallest integer subscripts


QUESTION : molecular formula - CORRECT ANSWER a formula for a
molecule in which the subscripts are whole-number multiples of the subscripts
in the empirical formula


QUESTION : stoichiometry - CORRECT ANSWER the calculation of the
quantities of reactants and products involved in a chemical reaction


QUESTION : interepreting a chemical equation - CORRECT ANSWER
the coefficients of the balanced chemical equation may be interpreted in terms
of either the numbers of molecules or the number of moles depending on your
needs


QUESTION : limiting reactant - CORRECT ANSWER the reactant that is
entirely consumed when a reaction goes to completion, once one reactant has
been completely consumed, the reaction stops, any problem giving the starting
amount for more than one reactant is a limiting reactant problem


QUESTION : theoretical yield - CORRECT ANSWER theoretical yield is
the maximum amount of product that can be obtained by a reaction from given
amounts of reactants-this is a calculated amount


QUESTION : actual yield - CORRECT ANSWER the amount of product
that is actually obtained-this is a measured amount




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