Energy, Environment, and Sustainability: Midterm Review

Comprehensive practice flashcards for the Energy, Environment, and Sustainability midterm review, covering energy mechanics, units, thermodynamics, fossil fuel geology, and nuclear physics.

Which recommended textbook and author are assigned for the course?

Energy, Environment and Sustainability (Edition 1 or 2) by Saeed Moaveni (with additional reference text Energy, Environment and Climate by Richard Wolfson).

What are the three major problems associated with humanity's current external energy consumption?

1) Societies rely heavily upon cheap external energy and have lost ancestral self-sufficiency knowledge; 2) Energy resources are being depleted at an alarming rate and will inevitably run out; 3) Energy consumption produces significant quantities of pollutants that adversely affect the environment and living organisms.

What two primary factors drive the demand for external energy over time, and what is the current global population growth rate?

Population growth (growing at approximately $1.1\%$) and economic activity (measured as GDP per capita, where a higher standard of living correlates with higher energy consumption).

What percentage of the world's external energy does the USA consume, and what percentage of the global population does it represent?

The USA consumes $17\%$ of the world's external energy while accounting for only $4\%$ of the world's population.

How much external energy does the USA produce versus consume (in thousand metric tons of oil equivalent), and what is the resulting deficit?

The USA produces $1785\text{ thousand metric tons of oil equivalent}$ and consumes $2191\text{ thousand metric tons of oil equivalent}$, creating a shortfall of $406\text{ thousand metric tons of oil equivalent}$.

What is the formula for calculating doubling time based on a constant percentage growth rate?

$$\text{Doubling Time} = \frac{70\text{ Years}}{\%\text{Growth Rate}}$$

If the population of a nation increases at a steady rate of $7\%$ per year, how many years will it take for the population to double?

$10\text{ years}$ ($\frac{70}{7} = 10$).

How is energy defined, and what is the definition and SI unit of mechanical work?

Energy is the capacity (or ability) to do work. Work is defined as $\text{Work} = \text{force} \times \text{distance in the direction of force} = F \times d$, which is measured in joules ($J$).

What does Newton's First Law of Motion state?

An object that does not experience a net external force continues to move in a straight line with constant speed (i.e., it does not accelerate).

What do Newton's Second and Third Laws of Motion state?

Newton's Second Law states that an object experiencing a net external force accelerates according to $F = ma$. Newton's Third Law states that for every action force, there is an equal and opposite reaction force.

What is the physical definition of $1\text{ joule}\,(J)$?

$1\text{ joule}$ is the amount of energy transferred when a force of $1\,N$ displaces an object through a distance of $1\,m$ in the direction of the force.

What are the conversion values of $1\,cal$, $1\,Cal$, $1\,BTU$, and $1\,kWh$ in joules ($J$)?

$1\,cal = 4.2\,J$; $1\,Cal = 1000\,cal = 1\,kcal = 4200\,J$; $1\,BTU = 1054\,J$; $1\,kWh = 3.6 \times 10^6\,J$.

How are the calorie ($cal$), food Calorie ($Cal$), and British Thermal Unit ($BTU$) defined in terms of water temperature change?

$1\,cal$ raises the temperature of $1\,g$ of water by $1\,^\circ\text{C}$; $1\,Cal$ raises the temperature of $1\,kg$ of water by $1\,^\circ\text{C}$; $1\,BTU$ raises the temperature of $1\,lb$ of water by $1\,^\circ\text{F}$.

What is the formula for kinetic energy, and by what factor does kinetic energy increase if an object's velocity is doubled?

$K = \frac{1}{2}mv^2$; doubling the velocity quadruples ($4\times$) the kinetic energy.

What is the formula for gravitational potential energy?

$$\text{Gravitational Potential Energy} = mgh = \text{weight} \times \text{height}$$

How is power defined, what is its primary SI unit, and how many watts are equivalent to $1\text{ horsepower}\,(hp)$?

Power is energy transferred per unit time ($\text{Power} = \frac{\text{Energy}}{\text{time}}$), measured in watts ($1\,W = 1\,J/s$). $1\,hp = 746\,W$.

How is thermal efficiency defined, and how is the overall efficiency of a multistep process determined?

$\text{Efficiency} = \frac{\text{Useful Energy Output}}{\text{Energy Input}} \times 100\%$. For a multistep process, overall efficiency is the product of individual efficiencies ($e_{\text{SYSTEM}} = e_1 \times e_2 \times e_3$), meaning system efficiency cannot exceed that of its least efficient step.

What distinguishes thermal energy, temperature, and heat from one another?

Thermal energy is the total internal kinetic energy of all particles in an object; temperature is the average kinetic energy per particle; heat is the thermal energy in transit between objects due to a temperature difference.

What formula calculates the sensible heat required to alter an object's temperature, and what does specific heat ($c$) quantify?

$\Delta Q = mc\Delta T$. Specific heat ($c$) is the quantity of heat required to change the temperature of a unit mass of a substance by $1\text{ degree}$.

What formula calculates the thermal energy transferred during a phase change?

$Q = mL$, where $m$ is the mass of the substance and $L$ is the latent heat.

How do black and white surfaces differ regarding thermal radiation emission, absorption, and reflection?

Black surfaces are good emitters, good absorbers, and poor reflectors; white surfaces are poor emitters, poor absorbers, and good reflectors.

In an idealized heat engine, what is the mathematical relationship between net work output ($W_{\text{out}}$), heat supplied ($Q_H$), and heat exhausted ($Q_C$)?

$W_{\text{out}} = Q_H - Q_C$, with thermal efficiency given by $e = \frac{W_{\text{out}}}{Q_H} = \frac{Q_H - Q_C}{Q_H}$.

What is the formula for the maximum theoretical efficiency ($e_{\max}$) of a heat engine operating between two thermal reservoirs?

$e_{\max} = 1 - \frac{T_C}{T_H}$, where both the cold reservoir temperature ($T_C$) and hot reservoir temperature ($T_H$) must be in kelvin ($K$).

What is the mechanical function of a heat pump in thermodynamics?

A heat pump consumes external work ($W_{\text{in}}$) to extract heat from a cold reservoir ($Q_C$) and exhaust heat into a hot reservoir ($Q_H$).

What does the Second Law of Thermodynamics state regarding isolated systems and heat engines?

The entropy of an isolated system never decreases over time (order proceeds toward disorder); consequently, no heat engine can convert $100\%$ of absorbed thermal energy into useful work without exhausting waste heat.

What classification framework is depicted in this diagram showing 'Reserves' versus 'Resources'?

The McKelvey Diagram, which categorizes total resources across increasing economic cost (vertical axis) and increasing geological uncertainty (horizontal axis), defining 'Reserves' as the subset that is well-identified and economically viable to extract.

What are the chronological ranks and stages of coal formation illustrated in this geological diagram?

Peat $\rightarrow$ Lignite (brown coal) $\rightarrow$ Sub-bituminous coal $\rightarrow$ Bituminous coal $\rightarrow$ Anthracite (formed under increasing time, heat, and overburden pressure).

What are the three distinct methods of coal mining used in the United States?

1) Underground Mining: follows coal seams below surface with shafts/tunnels; 2) Strip Mining: completely removes soil and rock overburden to expose coal beds; 3) Mountaintop Removal: blasts ridges and peaks away and dumps overburden into adjacent valleys.

What geological structure is depicted in this cross-section showing petroleum and natural gas trapping?

An anticlinal trap, where oil and gas migrate upward through permeable rock and are trapped beneath an impermeable layer of capstone rock.

How is crude petroleum separated into useful commercial products, and what product constitutes the single largest fraction?

Crude oil is separated by fractional distillation based on differing boiling points; approximately $45\%$ of a refinery's total yield is gasoline.

What is hydraulic fracturing ('fracking'), and what environmental concerns are associated with its use?

A technique using high-pressure fluid injection to shatter low-permeability rock and extract oil or natural gas. Key concerns include groundwater contamination, induced seismic activity (earthquakes), methane leakage, massive water usage, and potential blowouts.

Which US federal agency exercises primary regulatory oversight over civilian nuclear energy facilities?

The Nuclear Regulatory Commission (NRC).

Approximately what percentage of the electricity generated in the United States is supplied by nuclear energy?

Approximately $20\%$.

How does the physical size of an atomic nucleus compare to the overall atom, and what holds nucleons together?

The atomic nucleus is $10^5\text{ times}$ smaller than the entire atom. Nucleons are bound together by the strong nuclear force, an attractive short-range force that acts equally among protons and neutrons.

What types of nuclear radiation are differentiated by their behavior in a magnetic field in this experimental apparatus?

Alpha particles ($+2$ charge, helium nuclei deflected toward one pole), beta particles ($-1$ charge, electrons deflected strongly in the opposite direction), and gamma rays (electrically neutral ultra-high-energy photons proceeding undeflected).

What are the standard parent-to-daughter reaction equations for alpha decay, beta-minus decay, and beta-plus decay?

Alpha decay: ${}^A_Z\text{X} \rightarrow {}^{A-4}_{Z-2}\text{Y} + \alpha + \text{energy}$; Beta-minus decay: ${}^A_Z\text{X} \rightarrow {}^{A}_{Z+1}\text{Y} + e^- + \text{energy}$; Beta-plus decay: ${}^A_Z\text{X} \rightarrow {}^{A}_{Z-1}\text{Y} + e^+ + \text{energy}$.

What mathematical relationship describes the exponential decay of radioactive nuclei over time as a function of half-life?

$N = N_0 \left(\frac{1}{2}\right)^{t/t_{1/2}}$, where $N_0$ is the initial number of atoms, $t$ is elapsed time, and $t_{1/2}$ is the half-life.

What are the scientific fundamentals of Carbon-14 dating, and what is its effective chronological range?

It measures the remaining radioactive ${}^{14}\text{C}$ (half-life of $5730\text{ years}$) relative to ${}^{12}\text{C}$ (living ratio $1.35 \times 10^{-12}$), which ceases replenishment upon an organism's death; it is effective for biological artifacts up to about $40{,}000\text{ years}$ old.

What are the primary SI and conventional units of absorbed radiation dose, and what single dose is considered lethal?

The SI unit is the gray ($1\,Gy = 1.00\,J/kg$), and the traditional unit is the rad ($1\,rad = 0.01\,Gy$). An exposure of $500\,rem$ is lethal.

How does the biological damage caused by alpha radiation compare to that caused by beta radiation?

$1\,rad$ of alpha radiation causes the same biological tissue damage as $10\,rad$ of beta radiation, making alpha particles $10\text{ times}$ more damaging.

What balanced nuclear reaction equation represents the thermal neutron fission of Uranium-235 into Krypton and Barium?

$$^1n_0 + {}^{235}_{92}\text{U} \rightarrow {}^{91}_{36}\text{Kr} + {}^{142}_{56}\text{Ba} + 3\,^1n_0$$

Approximately how much energy is released by a single Uranium-235 fission event compared to the explosion of a molecule of TNT?

A single ${}^{235}\text{U}$ fission event releases about $200\,MeV$ ($3.2 \times 10^{-11}\,J$, or roughly $82\,TJ/kg$), whereas a molecule of TNT releases only about $30\,eV$.

What are the three primary components of a commercial nuclear fission reactor?

1) Nuclear fuel: pellets of ${}^{238}\text{U}$ enriched with approximately $3\%\,{}^{235}\text{U}$; 2) Control rods: neutron-absorbing materials that regulate or halt the chain reaction rate; 3) Coolant/moderator (such as pressurized heavy water): extracts fission heat to generate steam for electricity.

Why is it physically impossible for a commercial nuclear power plant to undergo a nuclear weapon-style explosion?

Commercial nuclear power plants use reactor fuel enriched to only approximately $3\%\,{}^{235}\text{U}$, whereas nuclear weapons require weapons-grade fuel enriched to approximately $90\%\,{}^{235}\text{U}$.

In what primary physical form is the vast majority of energy initially released and dispersed during nuclear fission?

The overwhelming release of energy is carried away as the kinetic energy of the positively charged fission fragments (krypton and barium nuclei repelled by electrostatic forces), which is rapidly converted via collisions into thermal internal energy (heat).