CHEM 121 MODULE 2 exam 2025 | ( QUESTIONS AND
WELL DETAILED ANSWERS) | ALREADY GRADED A+ |
LATEST UPDATE 2025/26
Empirical formula (how to find it %) - CORRECT ANSWER-1. divide each element %
by the atomic weight of the elem.
2. divide all numbers by smallest number in the group (including itself) to get a
second set of numbers
3. round up to nearest whole number, that is your formula
--if any of the numbers ends in a decimal that is equal to a fraction, multiply all
numbers by the denominator of that fraction and that will be your formula (exp.
0.25=1/4, 0.33=1/3, 0.5=1/2, 0.6=2/3, 0.75=3/4... exp. 3.5= 3(1/2)= 7/2= multiply
all numbers by 2
4. each whole number is the number of atoms of the element in the formula
balancing chemical equations - CORRECT ANSWER-1. dont change the subscript #'s
2. balance oxygen last, hydrogen second to last, and other atoms first
3. coefficients can only be placed in front of formulas, and applies to all atoms in
the compound
, 4. when counting, total # of atoms of that element is equal to coefficient*element
subscript*parenthesis subscript
my grammy is bigger than a mole - CORRECT ANSWER-grams are larger than moles.
so when finding an answer the grams (#) should always be larger than the moles
(#)
ionic equation - CORRECT ANSWER-tells what is actually happening at ionic level in
solution
net ionic equation - CORRECT ANSWER-actual reaction that occurs at ionic level,
spectator ions (ions that appear on both sides in the same form) are cancelled out
to het the net
5 types of reactions - CORRECT ANSWER-1. combination reactions
2. decomposition reactions
3. combustion reactions
4. double replacement reactions
5. single replacement reactions
combination (synthesis) reactions - CORRECT ANSWER-reaction in which single
product is formed from multiple reactants
WELL DETAILED ANSWERS) | ALREADY GRADED A+ |
LATEST UPDATE 2025/26
Empirical formula (how to find it %) - CORRECT ANSWER-1. divide each element %
by the atomic weight of the elem.
2. divide all numbers by smallest number in the group (including itself) to get a
second set of numbers
3. round up to nearest whole number, that is your formula
--if any of the numbers ends in a decimal that is equal to a fraction, multiply all
numbers by the denominator of that fraction and that will be your formula (exp.
0.25=1/4, 0.33=1/3, 0.5=1/2, 0.6=2/3, 0.75=3/4... exp. 3.5= 3(1/2)= 7/2= multiply
all numbers by 2
4. each whole number is the number of atoms of the element in the formula
balancing chemical equations - CORRECT ANSWER-1. dont change the subscript #'s
2. balance oxygen last, hydrogen second to last, and other atoms first
3. coefficients can only be placed in front of formulas, and applies to all atoms in
the compound
, 4. when counting, total # of atoms of that element is equal to coefficient*element
subscript*parenthesis subscript
my grammy is bigger than a mole - CORRECT ANSWER-grams are larger than moles.
so when finding an answer the grams (#) should always be larger than the moles
(#)
ionic equation - CORRECT ANSWER-tells what is actually happening at ionic level in
solution
net ionic equation - CORRECT ANSWER-actual reaction that occurs at ionic level,
spectator ions (ions that appear on both sides in the same form) are cancelled out
to het the net
5 types of reactions - CORRECT ANSWER-1. combination reactions
2. decomposition reactions
3. combustion reactions
4. double replacement reactions
5. single replacement reactions
combination (synthesis) reactions - CORRECT ANSWER-reaction in which single
product is formed from multiple reactants
