1
CHEM 335 Final Exam Questions and Answers |
100% Verified Answers| Updated 2024/2025.
What are the types of calculations in organic chemistry? -
(answer)Conversions, percent yield, mole fractions, mass percent, percent
recovery, proportionality
What are the two types of quantities used in organic chemistry calculations? -
(answer)Physical quantities and chemical quantities
What is chemical calculation? - (answer)A mathematical process of converting
a given physical quantity to the required chemical quantity
What are unit factors? - (answer)Factors used to convert between units of the
same quantity
What are dimensional factors? - (answer)Factors used to convert between
different quantities with different units
What is the formula for converting moles to mass? - (answer)Mass (g) = moles
x molar mass (g/mol)
What is the formula for converting mass to moles? - (answer)Moles = mass (g)
/ molar mass (g/mol)
What is the formula for converting moles to volume? - (answer)Volume (mL) =
moles x molar volume (mL/mol)
What is the theoretical yield? - (answer)The maximum quantity of product that
can be obtained from a reaction
, 2
What is the stoichiometric mole ratio? - (answer)The ratio of moles of
reactants and products in a balanced chemical equation
What is the formula for calculating percent yield? - (answer)Percent yield =
(actual yield / theoretical yield) x 100%
What is the purpose of calculating percent yield? - (answer)To determine the
efficiency of a reaction and the quality of the product obtained
What is the formula for calculating mole fraction? - (answer)Mole fraction =
moles of component / total moles of all components
What is the formula for calculating mass percent? - (answer)Mass percent =
(mass of component / total mass of mixture) x 100%
What is the formula for calculating percent recovery? - (answer)Percent
recovery = (recovered amount / initial amount) x 100%
What is proportionality in organic chemistry calculations? - (answer)The
relationship between two quantities that are directly proportional to each
other
What is the formula for calculating volume of a gas? - (answer)Volume (mL) =
moles x molar volume (mL/mol) x pressure (atm) / temperature (K)
What is the formula for calculating pressure of a gas? - (answer)Pressure (atm)
= moles x gas constant x temperature (K) / volume (L)
, 3
What is the formula for calculating percent yield? - (answer)[Experimental
mols / Theoretical mols ] x 100%
[Experimental grams / Theoretical grams ] x 100%
What is the formula for calculating theoretical yield? - (answer)Theoretical
yield = (MW of product / MW of limiting reagent) x moles of limiting reagent
What is the formula for calculating percent yield? - (answer)Percent yield =
(experimental yield / theoretical yield) x 100%
What is the formula for calculating mole fraction? - (answer)Mole fraction of
component X = moles of X / (moles of X + moles of Y)
What is the formula for calculating mole fraction? - (answer)Mole fraction of A
= (mass of A / MW of A) / [(mass of A / MW of A) + (mass of B / MW of B)]
What is the formula for calculating mass percentage? - (answer)Mass
percentage of component = (mass of component / total mass of mixture) x
100%
What is percent recovery? - (answer)Actual amount obtained divided by
expected amount multiplied by 100%
What is proportionality? - (answer)Two variables related by a constant
What is an example of direct proportionality? - (answer)Ratio of two variables
equals a constant
, 4
What is an example of indirect proportionality? - (answer)Product of two
variables equals a constant
What is a pure substance? - (answer)Homogeneous sample of same molecules
What is recrystallization? - (answer)Method to purify solids in lab
What are the types of impurities? - (answer)Soluble, insoluble, color
What are the effects of impurities? - (answer)Inhibit reactions, invalidate test
results
What are the learning outcomes of recrystallization? - (answer)Technique,
solvent selection, % recovery, impurity removal, melting point
What is the process of recrystallization? - (answer)Dissolve, cool, isolate pure
crystals
What is the principle of recrystallization? - (answer)Solubility enhanced by
mechanical action, solvent amount, temperature
What is the solubility of most solids in hot solvent? - (answer)Higher than in
cold solvent
What is recrystallization based on? - (answer)Temperature and solubility
characteristics
CHEM 335 Final Exam Questions and Answers |
100% Verified Answers| Updated 2024/2025.
What are the types of calculations in organic chemistry? -
(answer)Conversions, percent yield, mole fractions, mass percent, percent
recovery, proportionality
What are the two types of quantities used in organic chemistry calculations? -
(answer)Physical quantities and chemical quantities
What is chemical calculation? - (answer)A mathematical process of converting
a given physical quantity to the required chemical quantity
What are unit factors? - (answer)Factors used to convert between units of the
same quantity
What are dimensional factors? - (answer)Factors used to convert between
different quantities with different units
What is the formula for converting moles to mass? - (answer)Mass (g) = moles
x molar mass (g/mol)
What is the formula for converting mass to moles? - (answer)Moles = mass (g)
/ molar mass (g/mol)
What is the formula for converting moles to volume? - (answer)Volume (mL) =
moles x molar volume (mL/mol)
What is the theoretical yield? - (answer)The maximum quantity of product that
can be obtained from a reaction
, 2
What is the stoichiometric mole ratio? - (answer)The ratio of moles of
reactants and products in a balanced chemical equation
What is the formula for calculating percent yield? - (answer)Percent yield =
(actual yield / theoretical yield) x 100%
What is the purpose of calculating percent yield? - (answer)To determine the
efficiency of a reaction and the quality of the product obtained
What is the formula for calculating mole fraction? - (answer)Mole fraction =
moles of component / total moles of all components
What is the formula for calculating mass percent? - (answer)Mass percent =
(mass of component / total mass of mixture) x 100%
What is the formula for calculating percent recovery? - (answer)Percent
recovery = (recovered amount / initial amount) x 100%
What is proportionality in organic chemistry calculations? - (answer)The
relationship between two quantities that are directly proportional to each
other
What is the formula for calculating volume of a gas? - (answer)Volume (mL) =
moles x molar volume (mL/mol) x pressure (atm) / temperature (K)
What is the formula for calculating pressure of a gas? - (answer)Pressure (atm)
= moles x gas constant x temperature (K) / volume (L)
, 3
What is the formula for calculating percent yield? - (answer)[Experimental
mols / Theoretical mols ] x 100%
[Experimental grams / Theoretical grams ] x 100%
What is the formula for calculating theoretical yield? - (answer)Theoretical
yield = (MW of product / MW of limiting reagent) x moles of limiting reagent
What is the formula for calculating percent yield? - (answer)Percent yield =
(experimental yield / theoretical yield) x 100%
What is the formula for calculating mole fraction? - (answer)Mole fraction of
component X = moles of X / (moles of X + moles of Y)
What is the formula for calculating mole fraction? - (answer)Mole fraction of A
= (mass of A / MW of A) / [(mass of A / MW of A) + (mass of B / MW of B)]
What is the formula for calculating mass percentage? - (answer)Mass
percentage of component = (mass of component / total mass of mixture) x
100%
What is percent recovery? - (answer)Actual amount obtained divided by
expected amount multiplied by 100%
What is proportionality? - (answer)Two variables related by a constant
What is an example of direct proportionality? - (answer)Ratio of two variables
equals a constant
, 4
What is an example of indirect proportionality? - (answer)Product of two
variables equals a constant
What is a pure substance? - (answer)Homogeneous sample of same molecules
What is recrystallization? - (answer)Method to purify solids in lab
What are the types of impurities? - (answer)Soluble, insoluble, color
What are the effects of impurities? - (answer)Inhibit reactions, invalidate test
results
What are the learning outcomes of recrystallization? - (answer)Technique,
solvent selection, % recovery, impurity removal, melting point
What is the process of recrystallization? - (answer)Dissolve, cool, isolate pure
crystals
What is the principle of recrystallization? - (answer)Solubility enhanced by
mechanical action, solvent amount, temperature
What is the solubility of most solids in hot solvent? - (answer)Higher than in
cold solvent
What is recrystallization based on? - (answer)Temperature and solubility
characteristics
