Environmental Science Quiz on Gas Concentration
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Questions and Answers

What is the formula to convert concentration from mg/m3 at a specific temperature to mg/Nm3?

  • C_mg/Nm3 = C_T / (T1 - T2)
  • C_mg/Nm3 = C_T · (T2 / T1)
  • C_mg/Nm3 = C_T + (T1 / T2)
  • C_mg/Nm3 = C_T · (T1 / T2) (correct)

If the reference NOx emission factor is measured at 12% O2, what is the conversion factor to 10% O2?

  • 21 - OR
  • 21 - 10 (correct)
  • 21 - EM
  • 21 - OM

What is the molar weight of 1-butanol (C4H10O) calculated based on its molecular formula?

  • 82 g/mol
  • 62 g/mol
  • 58 g/mol
  • 74 g/mol (correct)

In the example provided, what concentration value falls within the range of 200-450 mg/Nm3?

<p>334.6 mg/Nm3 (A)</p> Signup and view all the answers

What is the flow rate of the flue gas stream mentioned for the spray booth?

<p>1200 m3/h (C)</p> Signup and view all the answers

At a temperature of 350°C, what is the additional constant added to the Celsius value for the conversion to Kelvin?

<p>273.15 K (A)</p> Signup and view all the answers

When converting the concentration of flue gas from mg/m3 to mg/Nm3, what temperature is commonly set as the reference point for mg/Nm3?

<p>0°C (C)</p> Signup and view all the answers

To find the moles in 1 m3 of the gas stream with 0.1% volume 1-butanol, what is the volume percentage equivalent to moles?

<p>0.1 moles (A)</p> Signup and view all the answers

Which of the following is NOT a type of contamination mentioned?

<p>Soil erosion (B)</p> Signup and view all the answers

What is the primary source of fuel leaks leading to groundwater contamination?

<p>Underground storage tanks (D)</p> Signup and view all the answers

Which of the following contaminants is specifically mentioned as a light hydrocarbon?

<p>Benzene (D)</p> Signup and view all the answers

BTEX is an acronym that includes which of the following compounds?

<p>Toluene (D)</p> Signup and view all the answers

What characteristic of benzene makes it particularly hazardous?

<p>It has a sweet smell (C)</p> Signup and view all the answers

Which contaminant is specifically noted for use in decaffeinating coffee?

<p>Benzene (A)</p> Signup and view all the answers

What is the molecular weight of carbon dioxide (CO2)?

<p>44 g/mol (D)</p> Signup and view all the answers

What type of hydrocarbons is particularly related to groundwater contamination from oil spills?

<p>Light hydrocarbons (B)</p> Signup and view all the answers

Which of these contaminants is a common byproduct of gasoline?

<p>MTBE (B)</p> Signup and view all the answers

At standard conditions (1 atm and 0°C), what is the volume of 1 mole of gas?

<p>22.414 L (C)</p> Signup and view all the answers

What is a common consequence of soil contamination with hydrocarbons?

<p>Impaired soil structure (C)</p> Signup and view all the answers

How is the number of moles in 1 m3 calculated?

<p>n = 44.615 moles (A)</p> Signup and view all the answers

Which factor contributes significantly to the volatilization of contaminants from soil?

<p>High temperatures (B)</p> Signup and view all the answers

What does 1 ppm represent in terms of gas concentration?

<p>1 mole of gas per 1 million moles (B)</p> Signup and view all the answers

What is Dalton's law primarily concerned with?

<p>The total pressure and partial pressures in a gas mixture (C)</p> Signup and view all the answers

How are the partial pressures of gases in a mixture related to their moles?

<p>They are directly proportional (C)</p> Signup and view all the answers

What is the advantage of using ppm and ppb as units of measure for gas pollutants?

<p>They remain unchanged under different conditions (C)</p> Signup and view all the answers

What is the numerical equivalent of 1 ppm in cm3 for 1 m3?

<p>1 cm3 in 1 m3 (C)</p> Signup and view all the answers

What does the formula for molarity express?

<p>Moles of solute per unit volume of solution (B)</p> Signup and view all the answers

Which unit is equivalent to ppm in terms of concentration in solid phase?

<p>mg/kg (D)</p> Signup and view all the answers

How would you express the conversion of mass/volume concentration to molarity?

<p>C = mol / volume (A)</p> Signup and view all the answers

If a solution has a concentration of 0.15 mol/L of NaCl, what is its mass concentration in mg/L?

<p>8767 mg/L (C)</p> Signup and view all the answers

What is the concentration of Fe in drinking water expressed in mg/L?

<p>200 mg/L (A)</p> Signup and view all the answers

Which of the following correctly defines ng/L concentration?

<p>Nanograms per liter (B)</p> Signup and view all the answers

What is the equivalent of ppb in terms of mass concentration?

<p>μg/kg (C)</p> Signup and view all the answers

What is the primary difference between sorption and absorption?

<p>Sorption refers to surface phenomena; absorption refers to bulk phenomena. (D)</p> Signup and view all the answers

Which term refers to the concentration expressed as mass/volume?

<p>Molarity (C)</p> Signup and view all the answers

What is the value of C in mg/Nm3 at 60°C if C in m3 is 2707?

<p>3302 mg/Nm3 (A)</p> Signup and view all the answers

What is the significance of the coefficient of dispersion 𝜎𝑗 in the expression for diffusivity?

<p>It influences the rate of spread of the pollutant. (B)</p> Signup and view all the answers

In the model for instantaneous point source, which component is specified as non-zero?

<p>𝐾𝑥𝑥, 𝐾𝑦𝑦, and 𝐾𝑧𝑧 (B)</p> Signup and view all the answers

What does the concentration formula for an instantaneous point source indicate about time t?

<p>Concentration decreases over time. (A)</p> Signup and view all the answers

In a continuous point source model, what is the nature of the plume?

<p>Steady-state (C)</p> Signup and view all the answers

How does the horizontal wind affect the concentration of pollutants in the formulas provided?

<p>It influences the distribution of the pollutant in the x direction. (D)</p> Signup and view all the answers

What assumption is made about the turbulence in the models discussed?

<p>Turbulence is homogenous and constant. (A)</p> Signup and view all the answers

In the two types of point source models described, what is the primary difference in the pollutant source strength?

<p>Instantaneous points use strength Q; continuous points use strength S. (A)</p> Signup and view all the answers

What is the relationship between the concentration and the variables 𝑦 and 𝑧 in the continuous point source model?

<p>Concentration depends inversely on 𝑦 and 𝑧. (A)</p> Signup and view all the answers

Which variable relates to the elevation from which flue gases are emitted?

<p>𝐻 (D)</p> Signup and view all the answers

What is a characteristic of Eulerian models in air dispersion?

<p>They employ a fixed reference system in Cartesian coordinates. (C)</p> Signup and view all the answers

In the mass budget equation for an Eulerian model, what does the 'S' term represent?

<p>The source term expressing how much pollutant appears. (D)</p> Signup and view all the answers

What is the main focus of continuous release models in air dispersion?

<p>Assessment of steady-state concentrations. (D)</p> Signup and view all the answers

What does the turbulent diffusion term depend on in the mass budget equation?

<p>The heterogeneity of the velocity field. (C)</p> Signup and view all the answers

Which of the following statements about puff models is correct?

<p>They divide the plume into finite volumes emitted at different times. (D)</p> Signup and view all the answers

What kind of pollutants were assessed in the impact study of gas boilers in Turin?

<p>NOx concentrations. (C)</p> Signup and view all the answers

In an air dispersion model, which factor is crucial for determining pollutant concentration?

<p>The flow rate and temperature of flue gas. (C)</p> Signup and view all the answers

What does the turbulent diffusivity tensor (Kjk) describe?

<p>The diffusion of pollutants due to turbulence. (B)</p> Signup and view all the answers

What does the variable 'c' represent in the mass budget equation?

<p>The concentration of the pollutant. (C)</p> Signup and view all the answers

How does an Eulerian model account for the advection of pollutants?

<p>Through fixed coordinates and velocity components. (A)</p> Signup and view all the answers

What is the main purpose of the climatological model in pollutant dispersion?

<p>To analyze long-term weather patterns. (B)</p> Signup and view all the answers

Which of the following best describes a continuous release model?

<p>It models a steady state for pollutant emissions. (C)</p> Signup and view all the answers

What is required for the mass balance equation to be solved effectively in air dispersion models?

<p>Detailed chemical reaction pathways. (A)</p> Signup and view all the answers

Flashcards

What is an aquifer?

A body of rock or sediment that is sufficiently porous and permeable to store and transmit significant quantities of groundwater.

What is the water table?

The upper surface of the zone of saturation, where the pores and fractures in the rock or sediment are fully saturated with water.

What is permeability?

The ability of a rock or sediment to transmit water. It is a measure of how easily water can flow through the material.

What is porosity?

The amount of pore space within a rock or sediment. It is a measure of the volume of void space in the material.

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What is a confined aquifer?

A type of aquifer in which the water table is confined by layers of impermeable rock or sediment. This type of aquifer is typically found in sedimentary basins.

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What is an unconfined aquifer?

A type of aquifer in which the water table is not confined by impermeable layers and is directly connected to the atmosphere. This type of aquifer is typically found in areas with shallow groundwater.

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What is a contamination pathway?

The process by which contaminated water moves through the soil and into the groundwater. Common pathways include leaking underground storage tanks and agricultural runoff.

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What are BTEX compounds?

A group of chemicals, including benzene, toluene, ethylbenzene, and xylene, that are commonly found in gasoline and other petroleum products. These chemicals can contaminate soil and groundwater and are harmful to human health.

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What is a free product (LNAPL) contamination?

A type of hydrocarbon contamination that occurs when gasoline or other petroleum products leak from underground storage tanks or other sources. The hydrocarbons form a separate layer floating on top of the groundwater.

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What is dissolved contaminant contamination?

A type of hydrocarbon contamination that occurs when dissolved hydrocarbons from a spill seep into groundwater.

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Partial pressure

The amount of pressure a gas would exert if it were the only gas in the volume.

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Dalton's Law

The total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas.

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ppm (Parts per million)

A way to express the concentration of a gas as the number of moles of that gas per million moles of air.

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ppb (Parts per billion)

A way to express the concentration of a gas as the number of moles of that gas per billion moles of air.

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Molar volume of an ideal gas

The volume occupied by one mole of an ideal gas at standard temperature and pressure (STP).

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Ideal Gas Law

The ideal gas law is a relationship between pressure, volume, temperature, and the number of moles of an ideal gas.

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Standard molar volume

The volume occupied by one mole of any ideal gas at standard temperature and pressure (STP), approximately 22.4 liters.

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Gas constant (R)

A constant that relates the pressure, volume, temperature, and number of moles of an ideal gas.

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What is the purpose of converting from mg/m3 to mg/Nm3?

The process of adjusting the concentration of a gas to account for the volume occupied by other gases, usually expressed in mg per Normal cubic meter (mg/Nm3).

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Why is temperature correction needed when converting to mg/Nm3?

This occurs when a gas is at a different temperature than the standard temperature (0°C or 273.15 K) used for mg/Nm3 calculations. The conversion factor is determined by the ratio of absolute temperatures.

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What is the purpose of converting the gas concentration to a reference oxygen content?

The process of adjusting the concentration of gas for the effects of oxygen content, ensuring that the gas concentration is referenced to a standardized oxygen level (usually 10%).

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How is the gas concentration converted to a reference oxygen content?

The concentration of a gas is adjusted based on the actual oxygen content in the gas stream and the desired reference oxygen concentration.

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What is the Best Available Technique Conclusions (BATC) approach?

A method used to estimate emission factors for different types of industrial processes.

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What is a reference NOx emission factor?

It is used in the BATC approach to represent the emission factors for NOx gases in mg/Nm3 at a specific oxygen concentration (typically 10%).

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How is the reference NOx emission factor adjusted for different oxygen concentrations?

The emission factor is adjusted based on the actual oxygen content in the gas stream and the desired reference oxygen concentration.

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What is the purpose of converting the volume of a gas to Nm3?

The volume of a gas is adjusted for the effects of temperature and oxygen content.

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Solid Phase Concentration

Expresses the mass of a substance per mass of the sample, commonly used for solid samples. Examples include parts per million (ppm) or parts per billion (ppb).

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Liquid Phase Concentration

Describes the concentration of a substance dissolved in a liquid, expressed as moles per unit volume (molarity) or mass per unit volume.

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Absorption

The assimilation of molecular species throughout the bulk of a solid material, where the substance penetrates and distributes within the whole material.

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Adsorption

The accumulation of a molecular species on the surface of a solid material, forming a layer on the surface.

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Concentration in mg/Nm3

A measure of the concentration of a substance expressed as milligrams per cubic meter.

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Concentration in ppm/ppb (Solid Phase)

Expresses the concentration of a substance in parts per million (ppm) or parts per billion (ppb) by weight, with 1 ppm equivalent to 1 mg/kg.

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Molarity to Mass/Volume Conversion

The conversion of molarity (mol/L) to mass/volume concentration (mg/L).

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Mass/Volume to Molarity Conversion

The process of converting mass/volume concentration (mg/L) back to molarity (mol/L).

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Liquid Phase Concentration: Mass/Volume Units

The concentration of a substance dissolved in water expressed in mg/L, μg/L, ng/L, or pg/L.

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Dalton's Law of Partial Pressures

The total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas.

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Eulerian Model

The dispersion of chemical substances in the atmosphere is described using a fixed coordinate system that is integral with the Earth's surface.

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Lagrangian Model

The dispersion of chemical substances is described by tracking the movement of individual particles.

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Puff Model

The plume of a pollutant is divided into small volumes (puffs) emitted at different times.

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Continuous Release Model

A continuous release model describes a steady emission of a pollutant from a source.

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Pollutant Accumulation

The accumulation of pollutants in a specific region at a given time.

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Pollutant Advection

The movement of a pollutant mass with the wind.

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Molecular Diffusion

The spread of pollutants due to random motion of air molecules.

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Turbulent Diffusion

The spread of pollutants due to turbulent air currents.

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Chemical Reactions

The chemical reactions that transform pollutants into other substances.

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Source Term

The rate at which a pollutant is released into the atmosphere.

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Reaction Term

The rate at which a pollutant is removed from the atmosphere through chemical reactions or other processes.

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Gridded Air Quality Model

A grid-based approach to understanding air pollution, including the concentration of pollutants at different locations.

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Mass Budget Equation

The equation that balances the terms contributing to the change of pollutant concentration in a specific spatial region.

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Air Quality Impact Assessment

The process of estimating the impact of air pollution from various sources.

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Air Dispersion Modeling

The process of using models to predict the concentration of pollutants at different locations in the atmosphere.

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Diffusivity

The ability of a pollutant to spread in a specific direction due to variations in air velocity.

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Diffusivity tensor component (Kjj)

A measure of the dispersion of a pollutant along a specific axis (x, y, or z). Expresses the ability of the pollutant to spread in that direction.

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Coefficient of dispersion (σj)

A coefficient representing the scale of pollutant dispersion along a specific axis, influencing the spread of the pollutant.

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Instantaneous point source

A simplified representation of the release of a pollutant that occurs instantaneously in a specific location.

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Concentration (c(x, y, z, t)) for an instantaneous point source

The concentration of a pollutant at a specific point (x, y, z) and time (t) after an instantaneous point source release.

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Continuous point source

A simplified representation of a continuous release of a pollutant from a specific location.

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Concentration (c(x, y, z)) for a continuous point source

The concentration of a pollutant at a specific point (x, y, z) after a continuous point source release at a steady-state condition.

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Stack emissions

The emission of flue gases from a stack or chimney typically at a specific elevation above the ground.

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Emission height (H)

The height of the emission source (e.g., the stack) above the ground.

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Constant and homogeneous turbulence

The constant and homogeneous turbulence in the atmosphere where the K components of the diffusion tensor are considered constant and independent of direction.

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