CHAPTER 3 AND 4: FINALS REVIEW Flashcards
What is energy?
The ability to do work or cause change
What are the different forms of energy?
- Electrical energy (energy caused by the ordered movement of electrons from one atom to another)
- Thermal energy (energy cause by the movement of particles)
- Radiation energy (energy stored in electromagnetic waves)
- Chemical energy (energy stored in molecular bonds)
- Wind energy (caused by the movement of air)
- Sound energy (energy stored in sound waves)
- Hydraulic energy (caused by the flow of water)
- Nuclear energy (energy stored in atomic nuclei)
- kinetic energy (energy of an object in movement)
- potential energy (energy an object could have based on mass and position )
what does W= F//D mean
work = force x distance
What does 1J equal to?
1Nx1m
What’s the difference between an energy transfer and an energy transformation?
Energy transfer: energy going from one place to another
vs
Energy transformation: energy changing from one form to another
What are the differences between opened systems, closed systems, and isolated systems?
Opened system: allows matter & energy in and out
Closed systems: allows matter and energy in but not out
Isolated system: does not let matter in nor out
When dealing with open systems, much of the energy is lost. If you had to calculate the energy efficency of a car, what formula would you use?
EE= (useful energy/total energy consumed) x 100
What is the law of conservation of energy?
- No energy is created nor lost, everything is simply tranferred or transformed
- The energy in an isolated system will always remain constant
What factors affect thermal energy?
More thermal energy: - More particles - Higher temperature Less thermal energy: -Less particles -Lower temperatures
What is the principle of heat?
Thermal energy will transfer from a hotter place to a colder place until both places are the same temperature
How would you calculate the relationship between heat and thermal energy?
Q=ΔEt
Q= heat (J)
ΔEt= variation in thermal energy (J)
What is the difference between heat and temperature?
Heat: the transfer of thermal energy
Temperature: The measure of the degree of agitation of the particles in a substance
What is specific heat capacity?
the amount of thermal energy needed to raise 1g of a substance by one degree celsius.
What is the specific heat capacity of water?
4.19J/°C
How do you calculate thermal energy?
Q=mcΔT Q = thermal energy (J) m= mass (g) c= specific heat capacity (J/°C) ΔT= variation in temperature
How would you calculate kinetic energy?
Ek= 0.5mv^2 Ek= kinetic energy (J) m= mass (kg) v= velocity in m/s
When the velocity of an object doubles…
Ek quadruples
How would you calculate gravitational potential energy?
Ep=mgh Ep= graviatational potential energy (J) m= mass (kg) g= gravitational field intensity h= height (m)
What is Mechanical energy? How would you calculate it?
The sum of Ek and Ep
Em= Ek+Ep
Emi=Emf
The law of conservation of energy states that in a frictionless system…
Em remains constant
What is force?
- Force is the factor which changes the motion or shape of an object through pushing and pulling.
- It is always represented by an arrow or a vector
- It accelerates or decerlerates an object as well as change its tradgectory
Force is represented in N, therefore…
F = N = kg x m/s^2
Gravitational force (fg) is the attraction between two bodies on account of their masses and the environment’s gravitational constant (acceleration of all free falling things regardless of mass). Therefore…
Fg = mg Fg= gravitational force (N) m= mass (kg) g= gravitational constant/field intensity
Speed is affected by the amount of distance over a certain time period. Therefore…
v= d/Δt v= velocity (m/s) d= distance (m) Δt= variation of time (s)
What is the difference between mass and weight?
Mass: the quantity of matter in an object
vs
Weight: Gravitational force acting on an object
What is effective force?
The force component that alters the motion of an object
How do you calculate sin, cos, and tan
sin = opp/hyp cos = adj/hyp tan = opp/adj
What is work?
when a force applied to an object causes it to move in the same direction of said force
What is the difference between a physical and chemical change?
Physical changes dont alter the nature nor the characteristics of matter, the atoms and molecules do not change
vs
Chemical changes DO alter the nature and characteristics of matter, the atoms and molecules DO change
What is a nuclear tranformation?
when the particles in the nucleus rearrange and new elements are created
What indicates chemical change?
release of gas, change of colour, release or taking iin of heat, emission of light, precipitate
State what symbols s,l,g, and aq stand for
solid, liquid, gas, aqueous
What rules must be followed when balancing chemical equations?
Coefs must be whole numbers and small as possible, new substances should never be added, substances should never be removed, subscripts must never be changed, should always be checked by counting atoms on each side
What is stoichiometry?
The study of the quantity of reactants required for reactions to occur and the quantity of transformed products
What is the difference between exothermic and endothermic reactions?
Exothermic: The release of heat
Endothermic: The absorption of heat
Reminder: The energy needed to break or form a bond depends on if they are single or double bonds.
Yeah.
How can you tell if a reaction is endothermic or exothermic?
Endothermic: Takes from the temperature around it, causes temperature of surrounding environment to decrease, will take in more enrgy
Exothermic: Releases energy in to environment, not in need of constant energy, will release more energy
What are the different types of chemical recations?
Synthesis: Reactants join to form a product
Decomposition: Compund that seperates into several compound
Precipitation: When an insoluble substnace is created from the combination of two solutions
Acid-Base neutralization: React with an acid and a base that result in water and salt
Oxidation: Where O is part of the given reactants
Combustion: Form of oxidation that releases a large amount of energy
Cellular respiration and photosynthesis:
- CR: chemical change where glucose and O are used to generate carbon dioxide and water
- PS: chemical change where carbon dioxide and water generate glucose and O
What is the triangle of fire?
What is needed to create combustion.
- Oxidizing agent: Substance to cause a fuel to react
- A fuel: substance that releases energy when reacting with O
- Ignition temperature: Minimum temp where energy is sufficient to start combustion
What are the three types of combustion?
Rapid combustion (e.g., burning candle), Spontaneous combustion(e.g, forest fires) , slow combustion (e.g., cellular respiration)
What is nuclear stability?
State of the nucleus in which the nuclear force is greater than the forces of electrical repulsion between protons
What is radioactivity?
the natural process where an unstable atom transforms into a more stable one(s) while releasing energy in the form of radiation
What is Half-life?
the time it takes for half the nuclei in a sample of radioactive material to decay
what is nuclear fission? Whats the difference between nuclear fusion?
when nuclei split to form two or more nuclei
vs when nuclei joing together to form a heavier nuclei
