FOR 2026/2027 PRACTICE QUESTIONS AND STUDY GUIDE
COMPLETE ACCURATE EXAM ACTUAL QUESTIONS AND CORRECT
VERIFIED ANSWERS WITH DETAILED RATIONALES (RELIABLE
SOLUTIONS) A NEW UPDATED VERSION 2026 EDITION ||JUST
RELEASED
balancing chemical equations with substitution
Fe2 O3 + H2 (SO4) -> Fe2 (SO4)3 + H2O; x=SO4; Fe2/2 O3/3 + 3H2/6
x/3 -> Fe2/2 *x3/3 + 3H2/6 O/3
balanced chemical equation
represents the relative amounts of substances required for a
complete chemical reaction to occur
mole
the SI base unit used to measure the amount of a substance
formula mass for covalent substances
formula represents the numbers and types of atoms composing a
single molecule of the substance; formula mass= molecular mass
,ex. chloroform (CHCl3)
(covalent compound) formula indicates that a single molecule
contains one carbon atom, one hydrogen atom, and three chlorine
atoms; avg molecular mass of chloroform= to sum of the avg. atomic
masses of these atoms
calculation used to derive molecular mass of chloroform
119.37 amu
formula mass for ionic compounds
quantity x avg. atomic mass (amu) = subtotal (each separate element)
and then add all together to get molecular mass
# of particles composing of a mole (named Avogadro's # or constant)
6.022 x 10^23
, molecular mass
The sum of the masses of all the atoms in a molecule; sometimes
called molecular weight; in grams of one mole of that substance
(grams per mole= g/mol)
mass and chemical composition of a substance
= # of moles and calculate # of atoms or molecules in sample
# of moles of substance
derive # of atoms or molecules and calculate substances mass
one mole
= molecular mass of element/ compound
percent composition
the elemental makeup of a compound defines its chemical identity,
and chemical formulas are the most succinct way of representing this
elemental makeup
when a compound's formula is unknown
= measuring mass of each of its elements is often the first step in the
process of determining the formula