Energy and the Environment Review Flashcards
(24 cards)
Definition of Energy?
The ability to do work
Definition of Work?
The act of moving something by force
Is energy a primary or secondary source?
Secondary because you need a primary source to create energy.
How is energy transferred for practical purposes?
We rely on energy transfers to create usable forms of energy to power not only our body’s, but our lives.
Why is hydrogen a good source of fuel?
Hydrogen is an abundant gas!
What are 2 main ways of creating hydrogen?
Electrolysis and Steam Reforming
How does Electrolysis work?
Electrolysis splits hydrogen from water; no harmful admissions
Cons of Electrolysis
VERY EXPENSIVE
What is Steam Reforming?
Steam reforming separates hydrogen from methane (CH4); less expensive than Electrolisis
CONS of steam reforming
edmits methane gas (leads to climate change)
How does a Fuel Cell Work?
1) Hydrogen is pumped into anode.
2) The Andone breaks hydrogen into hydrogen protons (H+) and electrons (e-)
3) ELECTRONS are forced to flow through the wire, because they can’t flow through the proton exchange membrane (electrolyte), and this creates energy
4) they meet at the Cathode (oxegen is pumped in) and then water is formed as a waste product
How does a battery work?
A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit. The flow of electrons provides an electric current that can be used to do work
What is energy efficiency?
Energy is the amount of useful energy you can get out of a system. (You want 100% efficiency)
What is the common source of energy lost during transfer?
Thermal heat energy
What is non-renewable energy?
Can’t be re-gained quickly
Examples: coal, natural gas, petroleum
Renewable energy
Can be re-gained in a short amount of time
Examples: wind and solar
Alternative energy
ALSO RENEWABLE but do not produce harmful emissions
Examples: Wind, Solar
What type of alternative energy is used most in the US? The midwest?
Wind power
What is a BTU?
BTU is British Thermal Units. These compare energy sources. We need these common units to be able to compare many sources that have different units.
What is One BTU
One BTU is the amount of energy needed to raise the temperature of one pound of water one degree.
What is Electricity?
The flow of electrons through a circuit.
What is Voltage?
Definition: Voltage is the energy pressure that pushes electrons in a circuit to make them move.
Symbol: V
Unit: Volts
What is Current
Definition: Current is the number of electrons flowing past a fixed point
Symbol: ?
Unit: Amps (A)
What is Electrical Power
Definition: Electrical power is the rate at which electricity is produced. Combo of voltage and current.
Symbol: P
Unit: Watts however we commonly use kWh when talking about electrical energy.
