Energy Flashcards
What is energy?
The ability to do work (exert a force over a distance)
What can energy be measured in?
- Joule
- calorie
- Calorie
- kWh
- BTU
How many joules are in 1 calorie?
1 cal = 4.19 J
How many joules are in 1 Calorie?
1 Cal = 1000 cal = 4190 J
How many kilojoules are in are in 1 kWh?
1 kWh = 3600 kJ
How many joules is in 1 BTU (heat)
1 BTU = 1054 J
Define: gross domestic product (GDP)
GDP measures the amount of goods and services a country produces in a year
Define: energy intensity
The energy used/GDP
How do you calculate energy intensity?
Country’s energy usage in a year / GDP
List some things that can contribute to a country having a low energy intensity
- High tech industries (use energy efficient methods)
- Rely on services more than goods (use less energy)
Why do developing nations tend to have higher energy intensities?
Because their economies tend to rely on natural resource technology that is less sophisticated and less efficient.
Why does Canada have a relatively high energy intensity?
Due to Canada’s high level of activity in mining petroleum and other natural resources as a result of our economy being industry based.
How does climate affect energy use?
Colder places need to burn more fossil fuels to stay warm, and hotter places need to burn more to stay cool.
How does economic activity affect energy use?
Making more goods and services requires energy (but services need less energy than goods)
How does population and development affect energy use?
Developed nations use more energy per capita
Define: input energy
The energy being put into an energy transformation process
Define: useful output energy
The useful energy that results from an energy transformation process
What is the formula for the efficiency of an energy transformation?
Efficiency % = (Output / Input) x 100
Define: fossil fuels
- Hydrocarbons that are used as fuel
- Derived from plants and animals that lived millions of years ago
Define: hydrocarbon
- An organic compound made up of carbon and hydrogen
Define: chemical potential energy
The energy stored in the chemical bonds of a substance
Define: non-renewable
A substance that can only be used once as it cannot be replenished in a short period of time
Define: radiant energy
Energy of electromagnetic radiation
How is the chemical potential energy stored in fossil fuels released?
During combustion reactions
What is the format of a combustion reaction?
Fuel + O2(g) = CO2(g) + 2H2O(g)
All combustion reactions are __________ reactions
All combustion reactions are exothermic reactions
In an exothermic reaction, the energy of the ________ must be less than the energy of the ___________
In an exothermic reaction, the energy of the products must be less than the potential energy of the reactants, as energy is released
What forms can the energy released during a combustion reaction be released as?
- Radiant energy (visible or IR light) can be emitted
- Kinetic energy of the particles can increase due to the increase in temperature
- Kinetic energy from warmer objects to cooler ones (heat)
Define: heat of combustion
The amount of energy that is released when something burns (heat of combustion is shown as a negative number to represent the energy LOST)
What is a calorimeter?
A device that is used to experimentally measure energy changes in reactions
What is calorimetry?
The process of measuring the amount of heat released or absorbed during a chemical reaction
What is the first law of thermodynamics? How does this relate to combustion reactions?
The Law of Conserving Energy
States that energy cannot be created or destroyed. This means the energy released by a reaction or system, must be gained by its surroundings
What is the second law of thermodynamics?
States that anytime energy is transferred, there is bound to be a loss of energy. If no transfer is 100% efficient, then there must always be a loss of energy
What is Hess’ Law?
A method used to theoretically determine the heat of combustion (or heat of a reaction in general)
What’s the difference between heat of combustion and heat of formation?
Heat of formation: the energy change involved when a compound is produced from its elements at standard conditions.
Heat of combustion: the energy change that occurs from a combustion reaction
Elements have a heat formation of _________
Elements have a heat formation of zero
How is electricity generated from Coal-Fired Generating Stations?
- The chemical potential energy in coal is released during combustion and absorbed by water
- The water boils and kinetic energy is released as high-pressure stream causes a turbine to spin
- Kinetic energy is transferred from the turbine, to the generator it is connected to, as a conductive wire spinning in a magnetic field generates a current
- Transmission lines are used to transfer electricity through the kinetic energy of electrons (movement of electrons)
Define: nucleons
Protons and neutrons and collectively known as nucleons because they are found in the nucleus
Atomic Number = ____________
Atomic Number = Number of Protons
Mass number = ____________ + ___________
Mass number =
# of protons + # of neutrons
What forces work inside the nucleus?
- Nuclear force: a force of attraction between protons and neutrons, and neutrons and neutrons
- Electrical force: a force or repulsion acting between protons
Neutrons ___________ the repulsive forces between protons (electrical force), but they __________ the nuclear force
Neutrons lessen the repulsive forces between protons (electrical force), but they increase the nuclear force
What happens if there are not enough neutrons in the nucleus of an atom? Why does this happen?
Radioactive decay will occur as a result. This is because the nuclear force is not strong enough to overcome the repulsive forces between protons, causing the nucleus to be unstable and breakdown
(Nuclear Force = low; Electric Force = high)
What are the three principle types of nuclear radiation?
- Alpha (α)
- Beta (β)
- Gamma (γ)
What is alpha decay?
When a nucleus decays or breaks down to give a stream of alpha particles (AKA alpha radiation)
What are alpha particles?
Nuclei that contain 2 protons and 2 neutrons. This is often represented as a helium atom because it has the same composition.
In a nuclear reaction, both the ____________ and the ____________ must be equivalent on both sides of the equation.
In a nuclear reaction, both the atomic number and the mass number must be equivalent on both sides of the equation.
What is beta decay?
When a nucleus decays or breaks down to give a stream of beta particles
Define: beta particle
An electron which is formed when a neutron is converted into a proton during a nuclear reaction, and is emitted from the nucleus.
Define: gamma decay
When a nucleus decays or breaks down to give a stream of gamma photons (rather than charged particles like alpha and beta). These are usually emitted along with an alpha or beta particle, but can be emitted on their own
Define: ionizing radiation
Radiation that ionizes the material they penetrate, leading to the formation of free radicals that can attack living tissue and damage DNA
Alpha, beta and gamma are all types of __________ __________.
Alpha, beta and gamma are all types of ionizing radiation
What is Geiger counter used for?
Used to detect α, β, γ radiation
What is “heavy hydrogen”?
Deuterium - an isotope of hydrogen with a mass number of 2 (has 1 neutron)
Define: fusion
Joining two small nuclei to form a larger nucleus with a simultaneous release of energy
How does fusion occur in the sun?
- Hydrogen to deuterium
- Deuterium to helium-3
- Helium-3 to helium-4
Where can deuterium be found?
Can be found in seawater
Fusion must take place at high ___________ & ____________
Fusion must take place at high temperatures** & **pressures*
What is cold fusion?
The theoretical method of causing fusion at more moderate temperatures
Define: fission
Splitting one nucleus to form two smaller nuclei with a simultaneous release of energy
Only ______ __________ is necessary to initiate a fission reaction, but the product neurons will start a _________ ___________
Only one neutron is necessary to initiate a fission reaction, but the product neurons will start a chain reaction
What is a CANDU reactor?
Canadian Deuterium Uranium Reactor
Converts intranuclear potential energy into kinetic energy of products
Kinetic energy heats water»_space;> steam»_space;> turn turbines to generate electricity
How is fission controlled?
- The moderation of the amount of U-235 in reactor
- Insert neutron absorbing rods into the reactor or liquids in emergency
- Use deuterium to absorb or slow neutrons so that they will collide with U-235
What happens as a result of uncontrolled fission?
- Nuclear bomb
- Meltdown of nuclear reactor (too much hear release)
How long do fission products emit ionizing radiation? How are they disposed of?
They emit ionizing radiation for thousands years. They are currently stored in water, and then are transported and secured away in concrete bunkers for a few years.
What formula can you use to convert mass to energy?
E = mc^2
When the sum of the product masses is ______ _____ the reactants, energy is made.
When the sum of the product masses is ______ ______ the reactants, energy is required.
When the sum of the product masses is LESS than the reactants, energy is made.
When the sum of the product masses is MORE than the reactants, energy is required.
What is the original source of energy for geothermal technology? How is this technology used?
Nuclear decay reactions that occur thousands of kilometres below the Earth’s surface.
It is used for heating or generating electricity
How does geothermal technology work?
By building energy stations near a source of fissure (pressurized steam), we can generate electricity similarly to fossil fuels, but without having to burn anything.
What is the original source of energy for tidal technology? How is it used?
Gravitational fields of the moon (and sun).
It is used to generate electricity
How is tidal energy harnessed?
Electricity is generated when the tide flows through the turbines in the barrage (barrier). The water is then held in an estuary and later used to generate electricity in the same way after high tide
How is solar power used?
Passive: involves the transfer of heat naturally. (conduction, convention, and radiation)
Active: uses a solar heat collector, which captures the Sun’s heat by using it to heat an anti-freeze solution. This is connected to a heating system that transfers thermal energy by pumping the solution into a heat exchanger where it releases the energy to water in a short-term storage bank
