CHEM103 / CHEM 103 Module 4: (Latest Update 2026 / 2027) General Chemistry I with Lab | Questions & Answers | Grade A | 100% Correct - Portage Learning

CHEM103 / CHEM 103 Module 4:
(Latest Update ) General
Chemistry I with Lab | Questions &
Answers | Grade A | 100% Correct -
Portage Learning

Composition of Substances & Solutions




Question:
mole
Answer:
an amount unit that provides a specific measure of the number of atoms or
molecules in a sample of matter




Question:
Avogadro's number (NA)
Answer:
6.02214076 x 10^23/mol

,Question:
molar mass of an element or compound
Answer:
grams per mole (g/mol)




Question:
the molar mass of a compound in grams is numerically equivalent to ____
Answer:
its formula mass in amu; g/mol = amu




Question:
calculating molar mass of a substance
Answer:
mass (g) / molar mass (g/mol) --> mol




Question:
percent composition
Answer:
the percentage by mass of each element in the compound

, Question:
percent composition formula (using H as example in CH cmpnd)
Answer:
%H = mass of H / mass of compound x 100%




Question:
what is percent composition useful for?
Answer:
evaluating the relative abundance of a given element in different compounds
of known formulas




Question:
empirical formulas are derived from experimentally measured element
masses by the following:
Answer:
1. Deriving the number of moles of each element from its mass.
2. Dividing each element's molar amount by the smallest molar amount to
yield subscripts for a tentative empirical formula.
3. Multiplying all coefficients by an integer, if necessary, to ensure that the
smallest whole-number ratio of subscripts is obtained.