CEN 304 EXAM 1

Match the following terms and their definitions

• when there is only one phase present and the substance cannot be removed from the liquid without accomplishing a phase change it is said to be:

  • Dissolved

• These are large enough to settle out of solution or be removed by filtration

  • Suspended solids

• Removed by centrifugation or filtration through very small pore spaces- not settling or normal filtration; Measured by using turbidity Nephelometric Turbidity Units (NTU)

  • Colloidal particles

True or False: 1ppmm equals 1 ug of pollutant per kg of solid (mg/kg)

• False

Al3+ has how many equivalents per mole?

• 3

Alkalinity is typically expressed as what?

• CaCO3

Henry’s Law constant refers to chemical equilibrium between air and what?

• Water

True or False: acidic solutions have pH<7

• True

Match the chemcial reaction type with the listed examples:

• precipiration-dissolution: Hard water forms scale on indoor plumbing

• Acid-Base chemisty: Disinfection using hypochlorous acid

• oxidation-reduction: Iron corrosion

• volatilization: Fumes from gasoline

• air-water equilibrium: A gas dissolving in a liquid

Alkalinity is a water’s capacity to neutralize acids, while buffering capacity is the ability of water to resist changes in pH when an acidic or alkaline material is added.

In most natural waters with pH= 6-8, the alkalinity is mostly due to what chemical species?

• HCO3-

What portion of the figure that would be the control volume for this set up?

What portion of the figure that would be the control volume for this set up?

What are the terms in a mass balance equation?

• Q*C

• m (m dot)

• dm/dt

• Q* Density

True or False: The following equation represents 1st order decay: dC/dt= -k

• False

State the following rate constant units indicate that a reaction is first order.

• /min

• /s

The graph below represents a 1st order reaction

The following equations would be used to calculate the half life of a chemical that degrades according to a 1st order reaction

• 0.693/k

You cannot treat a non-steady state problem as a steady state problem, but you can treat a steady state problem as a non-steady state problem

True or False: For a steady-state problem, the concentration is constant within the control volume.

• True

A sewer has been draining into a river for a long period of time. Would this be considered steady or non-steady state?

• Steady state

A sewer just started draining into a river. Would this be considered steady or non-steady state?

• non-steady state

True or False: For a PFR, there is a mixing in the axial direction

• False

Since there is a high inlet concentration that is diluted immediately for CMFRs, the reaction rate is low compared to a PFR

A PFR model is most appropriately used to model the following:

• pipe

A CMFR model us most appropriately used to model the following:

• Lake

• irrigation channel

• river

True or False: A PFR can achieve a higher removal efficiency for a given volume compared to a CMFR

• True

Greenhouse gases absorb most strongly in which part of the electromagnetic spectrum?

• infrared

True or False: Greenhouse gases occur naturally

• True

What is the name of the federal legislation first passed 1970 that defined the federal government’s responsibilities for protecting and improving the nation’s air quality?

• Clean Air Act

What are the Criteria Air Pollutants?

• CO

• NO2

• PM10

• O3

• SO2

• Pb

Define the following terms:

• Energy: Capacity to do useful work

• Work: Force acting on a body through a distance

• Power: Rate of doing work

• Specific heat: Quantity of het required to increase unit mass of a substance by one degree

• Latent heat of fusion: Energy to cause phase change from solid to liquid

• Latent heat of vaporization: Energy to cause phase change from liquid to gas

CO, HC, NOx represents the inputs for a catalytic converter that are removed while CO2, H2O, N2 represents its outputs

True or False: The EPA regulated based on the AQI

• False

True or FalseL NAAQS are enforced by the EPA

• False

The goal of the Cap and Trade system for acid rain was to reduce what following chemicals?

• SOx

• NOx

For adsorption systems, a collected pollutant remains in the adsorption bed, until bed becomes saturated and pollutant leaks out. This is called what?

• Breakthrough

Absorption which occurs in scrubbers is governed by partial pressure of the pollutant and Henry’s Law, while Adsorption can be done with active carbon is governed by the Langmuir isotherm.

Renewable resources can be replenished by natural processes with a human timescale while sustainable resources can be used for a very long time without causing substantial harm to humans or the natural environment

True or False: The price of solar cells is increasing

• False

What renewable resources are considered intermittent?

• Solar

• Wind Power

True or False: As one rises up into the atmosphere, the temperature always decreases.

• False

During unstable conditions vertical movement of an air parcel in the atmosphere is encouraged upward or downward, while during stable conditions vertical movement of an air parcel is discouraged

The following model shows the atmospheric temperature profile on the left that is most likely to lead to the looping plum seen on the right

True or False: A gamma value of -5 C/km represents a stable atmosphere.

• True

The following model should the atmospheric temperature profile on the left that is most likely to lead to fumigation as seen on the right.

Pro and Cons of Hydroelectric Power

• Pros:

  • Highly efficient in terms of emissions

  • long operating life with proper maintenance

  • flood control

• Cons

  • Energy output depends on the amount of precipitation

  • high initial costs

  • needs regular maintence

Pros and Cons of Solar

• Pros

  • Infinite Supply/Renewable energy source

  • Lower electricity bills

  • reduce carbon footprint

• Cons

  • Expensive startup costs

  • sun is not always there

  • need to mine for batteries

Pros and Cons of Biomass(firewood)

• Pros

  • Renewable due to the organic materials

  • planting tree/growing forests could offset the CO2

  • Using local firewood diminishes transportation cost

• Cons

  • Harmful pollutants are released

  • potential concern about deforestation

  • expensive

Pros and Cons of Biofuels (corn-based)

• Pros

  • lower greenhouse gas emmissons

  • waste reduction

  • reducted air pollutants

• Cons

  • high production cost

  • less efficient than fossil fuels

  • land use/deforestation

Pros and Cons of Geothermal

• Pros

  • Small land footprint

  • renewable and sustainable

  • pollution decrease

• Cons

  • high initial costs

  • location dependence

  • scaling limitations