Energy Flashcards
What is energy?
The capacity to do work or to produce change
How is energy expressed?
Joules
1N=?
100g
Joules=
Newtons x meters
What is thermal energy?
Energy that comes from the random motion of the particles that make up a substance
What is temperature?
Degree of agitation in a substances atoms and molecules
What factors can affect thermal energy?
Temperature and amount of particles
What happens when there is a higher temperature?
Particles move faster, higher thermal energy
What happens when there are more particles in a substance
More collisions, more thermal energy
What is radiant energy?
The kind of energy that is contained in and transported by electromagnetic waves
What is wavelength
The distance form crest to crest
What does the amount of energy depend on?
Wavelength and radiation
Chemical energy
Energy stored in the bonds of a molecule
What does the amount of energy depend on?
Strength of a bond
What happens when there is a stronger bond?
More energy
What is mechanical energy?
Energy that results from the speed of an object, its mass and its surroundings
What happens with speed?
Energy increases
What happens with more mass
Greater the mechanical energy
More mass
More energy
What is Energy transformation ?
Changing of energy from one form to another
What is an example of energy transformation?
When a log burns some of the chemical energy stored in the wood is transformed into radiant energy and thermal energy
Is a lamp an energy transformation or transfer? What does it change to ?
Energy transformation
Electrical - thermal + radiant
Other examples of energy transformations
Photosynthesis -radiant to chemical
Windmill - mechanical to mechanical
What is an energy transfer?
Movement of energy form one place to another
Examples of energy transfer
Heat = transfer of thermal energy ex: burning log - heat the room
Heat
A transfer of thermal energy between two places with different temps
Heat travels from places with high temp to low
What is a physical change?
A phish also change does not effect the nature or the characteristic properties of matter
What are Changes of state ?
Transformation from one state to another
What happens in a change of state?
The forces of attraction change but the particles don’t.
What happens when we heat water?
Thermal energy is transferred from heating element to after. The liquid particles are sped up enough until they have absorbed enough energy to go from liquid to gas
Energy is absorbed
What happens when we freeze water?
Heat transfers from an area of hot towards cold
Water transfers it’s heat to the cold freezer, lowering the waters temp
Energy is given off
What is dissolution?
The creation of a solution by a solute in a solvent
What happens when sugar dissolves in water?
Sugar molecules break apart until they are spread out in the water.
Sugar and water don’t change.
The forces of attraction change
What is exothermic?
Reactions that release energy, increasing the energy level of their environment. This may be noticeable by an increase in temp or emission of light
What is endothermic?
Reactions that by absorbing energy, lower the energy level of the medium. This can be perceptible by a drop in temperature
What is deformation?
Changing the shape of a material with an energy transfer (reversible or permanent)
What is an example of a deformation?
Mechanical from a jumper causes the reversible deformation of a trampoline (mechanical into elastic energy)
Smashing a calculator (permanent)
What is a chemical change?
Changes the nature and characteristic properties of matter. It produces one or more new substances. Bonds between the atoms are changed to create new products
Law of conservation of mass
Nothing is lost, nothing is created, all is transformed
How are chemical reactions represented
In equations
Reactant —> product
Clues to see if a chemical reaction has occurred
Release of gas Greater change of heat Generation of light Change of colour Formation of precipitate
What is synthesis?
Formation of a complex molecule from atoms or simpler molecules
Example of synthesis
2H2+ o2 —> 2H2O +energy
Synthesis of water (releases energy)
N2 +2O2 +energy —> 2NO2
Nitrogen dioxide synthesis (absorbs energy)
Decomposition
Transformation of complex molecules into simpler molecules or into atoms
Example of decomposition
2H2O +electrical energy —> 2H2+O2
Electrolysis of water
What happens by the end of decomposition?
The chemical energy that was stored in the bonds of the molecule is released and transformed into other forms of energy
What is oxidation ?
Chemical reaction involved mg oxygen or a substance that has similar properties (sulfate, chlorine, Fluoride,)
Example of oxidation
4Fe +3O2 —> 2Fe2O3 + energy
Rust
Precipitation
Formation of a solid that I sleds soluble, or not soluble, following the mixing of two solutions
Example of precipitation
NaCl +AgNO3 _> NaNo3 + AgCl
Led nitrate with potassium iodide
KL +Pb (NO3)2 —> KNO3 + Pbl2
