General Chemistry Exam 2 Questions
With All Correct Answers 2025 Latest
Update
How to find the mass of a molecule? CORRECT ANSWERS g molecule --> mol
molecule --> Avogadro's #
Example:
(1 mol CO.01g CO2)
x
(6.022 x 10^23 CO2 molecules / 1 mol CO2)
OR (to organize the equation/steps)
(44.01g CO mol CO2)
x
(1 mol CO.022 x 10^23 CO2 molecules)
Mass Percent Composition
(Mass Percent) CORRECT ANSWERS (Mass of element X in 1 mol of compound /
Mass of 1 mol of the compound) x 100%
Example:
(2 x molar mass Cl / molar mass CCl2F2) x 100%
How to calculate the number of moles of each element that are present in each sample?
CORRECT ANSWERS Example:
0.857g H x (1 mol H / 1.01 g H) = 0.849 mol H
6.86g O x (1 mol O / 16.00g O) = 0.429 mol O
[Divide each # of moles by fewest moles]
0.849 mol H / 0.429 = 1.98 => 2
0.429 mol O / 0.429 = 1
So, the empirical compound of Hydrogen and Oxygen is H2O
How to calculate Molecular Mass [n]
,(After finding Empirical Formula and given Molar Mass in the problem)? CORRECT
ANSWERS Molecular Mass [n] =>
(molar mass / empirical formula molar mass)
Elemental Analysis CORRECT ANSWERS A method of obtaining Empirical Formulas
for unknown compounds (containing C and H) by burning a sample of the compound in
pure oxygen and analyzing the products of the combustion reaction.
What must be in equilibrium in a "balanced" chemical reaction? CORRECT ANSWERS
1.) The number of atoms
2.) The amount of mass
Organic Compounds CORRECT ANSWERS A compound composed of C and H and
other elements: N, O, and S.
Example: Methane (CH4)
Hydrocarbons CORRECT ANSWERS Organic Compounds composed of only C and H.
Alkanes, Alkenes, Alkynes (# of bonds)? CORRECT ANSWERS Alkanes =>
Hydrocarbons with single-bonded carbons
Alkenes =>
Hydrocarbons with double-bonded carbons
Alkynes =>
Hydrocarbons with triple-bonded carbons
Base Names for Hydrocarbons CORRECT ANSWERS meth = 1
eth = 2
prop = 3
but = 4
pent = 5
hex = 6
hept = 7
oct = 8
non = 9
dec = 10
The Greenhouse Effect CORRECT ANSWERS Greenhouse gases in the atmosphere
act as a one-way filter.
They allow sunlight to pass through and warm Earth's surface.
, Prevent heat energy from radiating back out into space.
Stoichiometry CORRECT ANSWERS The numerical relationships between the amount
of reactants and the amount of products in a balanced chemical equation.
Coefficients in a Chemical Reaction (function) CORRECT ANSWERS The amounts (in
moles) of the reactants and the products in a chemical reaction.
Limiting Reactant (Reagent) CORRECT ANSWERS The reactant that has the smallest
stoichiometric amount in a reactant mixture and hence limits the amount of product in a
chemical reaction.
The reactant that makes the least amount of product.
Completely consumed in a chemical reaction
NOTE:
- Also called "limiting reagent"
Excess Reactant (Reagent) CORRECT ANSWERS The reactants that do not limit the
amount of product (in excess)
Usually greater than what is required to completely react with the limiting reactant.
Theoretical Yield CORRECT ANSWERS The maximum possible amount (in grams) of
product that can be made in a chemical reaction based on the amount of limiting
reactant.
TY = [Amount of product by limiting reactant]
x
[Molar mass of product]
Actual Yield CORRECT ANSWERS The amount of product ACTUALLY produced by a
chemical reaction.
Always equal to or less than the Theoretical Yield because a small mount of product is
usually lost to other reactions or foes not form during a reaction.
Percent Yield CORRECT ANSWERS The percentage of the Theoretical Yield that was
actually obtained.
Expressed as the ratio of the actual yield to the theoretical yield.
% Yield =
(Actual amount of product formed/
Maximum [possible] amount of product) x 100%
With All Correct Answers 2025 Latest
Update
How to find the mass of a molecule? CORRECT ANSWERS g molecule --> mol
molecule --> Avogadro's #
Example:
(1 mol CO.01g CO2)
x
(6.022 x 10^23 CO2 molecules / 1 mol CO2)
OR (to organize the equation/steps)
(44.01g CO mol CO2)
x
(1 mol CO.022 x 10^23 CO2 molecules)
Mass Percent Composition
(Mass Percent) CORRECT ANSWERS (Mass of element X in 1 mol of compound /
Mass of 1 mol of the compound) x 100%
Example:
(2 x molar mass Cl / molar mass CCl2F2) x 100%
How to calculate the number of moles of each element that are present in each sample?
CORRECT ANSWERS Example:
0.857g H x (1 mol H / 1.01 g H) = 0.849 mol H
6.86g O x (1 mol O / 16.00g O) = 0.429 mol O
[Divide each # of moles by fewest moles]
0.849 mol H / 0.429 = 1.98 => 2
0.429 mol O / 0.429 = 1
So, the empirical compound of Hydrogen and Oxygen is H2O
How to calculate Molecular Mass [n]
,(After finding Empirical Formula and given Molar Mass in the problem)? CORRECT
ANSWERS Molecular Mass [n] =>
(molar mass / empirical formula molar mass)
Elemental Analysis CORRECT ANSWERS A method of obtaining Empirical Formulas
for unknown compounds (containing C and H) by burning a sample of the compound in
pure oxygen and analyzing the products of the combustion reaction.
What must be in equilibrium in a "balanced" chemical reaction? CORRECT ANSWERS
1.) The number of atoms
2.) The amount of mass
Organic Compounds CORRECT ANSWERS A compound composed of C and H and
other elements: N, O, and S.
Example: Methane (CH4)
Hydrocarbons CORRECT ANSWERS Organic Compounds composed of only C and H.
Alkanes, Alkenes, Alkynes (# of bonds)? CORRECT ANSWERS Alkanes =>
Hydrocarbons with single-bonded carbons
Alkenes =>
Hydrocarbons with double-bonded carbons
Alkynes =>
Hydrocarbons with triple-bonded carbons
Base Names for Hydrocarbons CORRECT ANSWERS meth = 1
eth = 2
prop = 3
but = 4
pent = 5
hex = 6
hept = 7
oct = 8
non = 9
dec = 10
The Greenhouse Effect CORRECT ANSWERS Greenhouse gases in the atmosphere
act as a one-way filter.
They allow sunlight to pass through and warm Earth's surface.
, Prevent heat energy from radiating back out into space.
Stoichiometry CORRECT ANSWERS The numerical relationships between the amount
of reactants and the amount of products in a balanced chemical equation.
Coefficients in a Chemical Reaction (function) CORRECT ANSWERS The amounts (in
moles) of the reactants and the products in a chemical reaction.
Limiting Reactant (Reagent) CORRECT ANSWERS The reactant that has the smallest
stoichiometric amount in a reactant mixture and hence limits the amount of product in a
chemical reaction.
The reactant that makes the least amount of product.
Completely consumed in a chemical reaction
NOTE:
- Also called "limiting reagent"
Excess Reactant (Reagent) CORRECT ANSWERS The reactants that do not limit the
amount of product (in excess)
Usually greater than what is required to completely react with the limiting reactant.
Theoretical Yield CORRECT ANSWERS The maximum possible amount (in grams) of
product that can be made in a chemical reaction based on the amount of limiting
reactant.
TY = [Amount of product by limiting reactant]
x
[Molar mass of product]
Actual Yield CORRECT ANSWERS The amount of product ACTUALLY produced by a
chemical reaction.
Always equal to or less than the Theoretical Yield because a small mount of product is
usually lost to other reactions or foes not form during a reaction.
Percent Yield CORRECT ANSWERS The percentage of the Theoretical Yield that was
actually obtained.
Expressed as the ratio of the actual yield to the theoretical yield.
% Yield =
(Actual amount of product formed/
Maximum [possible] amount of product) x 100%
