ENVH.310- FINAL EXAM QUESTIONS & ANSWERS
What is homogeneous chemical equilibrium? - Answers -All reactants and products are
in the same physical state and occur in unison
What is heterogeneous chemical equilibrium? - Answers -Reactants and products exist
in two or more physical states
How is chemical equilibrium shifted in water/wastewater treatment? - Answers -By
precipitation reactions, oxidation-reduction reactions, acid-base reactions
(neutralization), and gas-producing reactions.
What are precipitation reactions? - Answers -Reactions that form insoluble precipitates
of unwanted substances by adding treatment chemicals (e.g., lime, aluminum sulfate)
Define oxidation and reduction. - Answers -Oxidation = removal of electrons; Reduction
= addition of electrons.
What happens in acid-base neutralization reactions? - Answers -Equivalent amounts of
acid and base neutralize each other to form a salt solution
What are gas-producing reactions? - Answers -Reactions where a gas product escapes
from solution (e.g., ammonia stripping)
What is kinetics? - Answers -The study of the rate of reactions
What is a zero-order reaction? - Answers -A reaction rate independent of the
concentration of any reactant or product.
What is a first-order reaction? - Answers -A reaction rate directly proportional to the
concentration of one reactant.
How does temperature affect reaction rate? - Answers -Rate of reaction increases with
increasing temperature.
Identify the factors influencing gas solubility in water. - Answers -temperature, partial
pressure, and the nature of the gas and solvent
What are colloids in water? - Answers -Turbidity-producing substances with large
surface area (1-500 nm) that don't settle out easily.
Describe how the process of coagulation removes them from water and wastewater. -
Answers -By adding positively charged chemical coagulants, such as alum or ferric
sulfate, which neutralize the colloids' negative charges
, State why the use of standard solutions is necessary in laboratory chemical analyses. -
Answers -To provide a known reference for accurately determining the concentration of
unknown substances through processes like titration, instrument calibration, and quality
control
Describe the purpose of analyzing for Alkalinity and acidity - Answers -Alkalinity and
acidity represent the buffering capacity of water, or its ability to resist changes in pH
Describe the purpose of analyzing for Hardness - Answers -Water hardness is caused
primarily by dissolved minerals, particularly calcium and magnesium. Water that is too
hard can damage pipes and appliances, but water that is too soft can be corrosive.
Describe the purpose of analyzing for Iron and manganese - Answers -Iron and
manganese are common metals found in groundwater that can cause aesthetic and
operational problems, but typically do not pose a health risk.
Describe the purpose of analyzing for Tubidity - Answers -Turbidity is the measure of
water's clarity or cloudiness, caused by suspended particles like clay, silt, organic
matter, and microbes.
Describe the purpose of analyzing for Nitrogen and phosphorous - Answers -Nitrogen
and phosphorus are essential nutrients, but excessive amounts in water can cause a
number of adverse ecological effects.
Describe the purpose of analyzing for Dissolved oxygen - Answers -Dissolved oxygen
(DO) is the amount of molecular oxygen (O2) present in water and is one of the most
important indicators of water quality.
Identify the basis of Alkalinity and acidity - Answers -titration
Identify the basis of Hardness - Answers -titration
Identify the basis of Iron and manganese - Answers -oxidation
Identify the basis of Turbidity - Answers -light scattering
Identify the basis of Nitrogen and phosphorous - Answers -colormetric analysis
Identify the basis of Dissolved oxygen - Answers -titration
Five key components of the hydrologic cycle. - Answers -a. evaporation, sublimation,
transpiration, and evapotranspiration (ESTE) b. condensation c. precipitation d. runoff e.
water storage
What is evapotranspiration? - Answers -Evapotranspiration is the combined process of
evaporation and transpiration from the Earth's surface.
What is homogeneous chemical equilibrium? - Answers -All reactants and products are
in the same physical state and occur in unison
What is heterogeneous chemical equilibrium? - Answers -Reactants and products exist
in two or more physical states
How is chemical equilibrium shifted in water/wastewater treatment? - Answers -By
precipitation reactions, oxidation-reduction reactions, acid-base reactions
(neutralization), and gas-producing reactions.
What are precipitation reactions? - Answers -Reactions that form insoluble precipitates
of unwanted substances by adding treatment chemicals (e.g., lime, aluminum sulfate)
Define oxidation and reduction. - Answers -Oxidation = removal of electrons; Reduction
= addition of electrons.
What happens in acid-base neutralization reactions? - Answers -Equivalent amounts of
acid and base neutralize each other to form a salt solution
What are gas-producing reactions? - Answers -Reactions where a gas product escapes
from solution (e.g., ammonia stripping)
What is kinetics? - Answers -The study of the rate of reactions
What is a zero-order reaction? - Answers -A reaction rate independent of the
concentration of any reactant or product.
What is a first-order reaction? - Answers -A reaction rate directly proportional to the
concentration of one reactant.
How does temperature affect reaction rate? - Answers -Rate of reaction increases with
increasing temperature.
Identify the factors influencing gas solubility in water. - Answers -temperature, partial
pressure, and the nature of the gas and solvent
What are colloids in water? - Answers -Turbidity-producing substances with large
surface area (1-500 nm) that don't settle out easily.
Describe how the process of coagulation removes them from water and wastewater. -
Answers -By adding positively charged chemical coagulants, such as alum or ferric
sulfate, which neutralize the colloids' negative charges
, State why the use of standard solutions is necessary in laboratory chemical analyses. -
Answers -To provide a known reference for accurately determining the concentration of
unknown substances through processes like titration, instrument calibration, and quality
control
Describe the purpose of analyzing for Alkalinity and acidity - Answers -Alkalinity and
acidity represent the buffering capacity of water, or its ability to resist changes in pH
Describe the purpose of analyzing for Hardness - Answers -Water hardness is caused
primarily by dissolved minerals, particularly calcium and magnesium. Water that is too
hard can damage pipes and appliances, but water that is too soft can be corrosive.
Describe the purpose of analyzing for Iron and manganese - Answers -Iron and
manganese are common metals found in groundwater that can cause aesthetic and
operational problems, but typically do not pose a health risk.
Describe the purpose of analyzing for Tubidity - Answers -Turbidity is the measure of
water's clarity or cloudiness, caused by suspended particles like clay, silt, organic
matter, and microbes.
Describe the purpose of analyzing for Nitrogen and phosphorous - Answers -Nitrogen
and phosphorus are essential nutrients, but excessive amounts in water can cause a
number of adverse ecological effects.
Describe the purpose of analyzing for Dissolved oxygen - Answers -Dissolved oxygen
(DO) is the amount of molecular oxygen (O2) present in water and is one of the most
important indicators of water quality.
Identify the basis of Alkalinity and acidity - Answers -titration
Identify the basis of Hardness - Answers -titration
Identify the basis of Iron and manganese - Answers -oxidation
Identify the basis of Turbidity - Answers -light scattering
Identify the basis of Nitrogen and phosphorous - Answers -colormetric analysis
Identify the basis of Dissolved oxygen - Answers -titration
Five key components of the hydrologic cycle. - Answers -a. evaporation, sublimation,
transpiration, and evapotranspiration (ESTE) b. condensation c. precipitation d. runoff e.
water storage
What is evapotranspiration? - Answers -Evapotranspiration is the combined process of
evaporation and transpiration from the Earth's surface.
