Energy Changes Flashcards

1
Q

what is energy not?

A

not a mass, not matter, not a substance, does not take up space

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2
Q

energy is?

A

a measure of the ability to cause change to occur

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3
Q

what process releases energy?

A

exothermic

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4
Q

what process has flames?

A

exothermic

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5
Q

what process creates products that are hotter than the reactants?

A

exothermic

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6
Q

who is the worst teacher employed at Garnet Valley?

A

Mrs. Stein

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7
Q

what does a molecular covalent compound react with/ produce?/ what type of reaction is it?

A

reacts with Oxygen/ produces C02 and water. and also heat, light, and flames. Exothermic

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8
Q

what type of reactions produce heat and light, but no flames?

A

when a metal or elemental metal reacts with oxygen. exothermic

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9
Q

what type of changes are related to exothermic changes?

A

big changes in matter (fire)

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10
Q

what is the remaining ash and charred fuel from a fire from?

A

they are the results of reactants that did not react completely

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11
Q

what distinguishes an exothermic process?

A

flames, heat

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12
Q

how is the glowing yellow color of a wood fire caused?

A

particles of carbon are carried into the air by the gaseous products of the exothermic reaction

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13
Q

what are changes of matter accompanied by?

A

a change in matter

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14
Q

what is heat?

A

the transfer of energy between 2 objects, due to temp differences

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15
Q

what is the system?/ what is it used for

A

the matter you are focusing on/ its used to represent where heat is transferring from or transferring to (substance)

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16
Q

what is the surroundings?

A

is anything else that surrounds the system (the environment. beaker, thermometer)

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17
Q

how are chemical changes categorized?

A

by the direction of heat transfer

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18
Q

what is endothermic?

A

when heat if transferred from the surrounding to the system

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19
Q

cold is experienced with what process?

A

exothermic

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20
Q

what is kinetic energy?

A

the energy of motion

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21
Q

what is a reflection of average kinetic energy of a sample?

A

temperature

22
Q

if the products of a reaction are hotter than the reactants, they must be __________

A

moving faster

23
Q

what reaction launches a space shuttle?

A

reaction between H2 and O2, which produces H2O, and is very exothermic

24
Q

hotter products mean _____ particles

A

faster moving

25
Q

colder products mean _______ particles

A

slower moving

26
Q

what are the 3 main ways heat is transfered?

A
  • conduction
  • convection
  • radiation
27
Q

what is conduction heat transfer

A

takes place when a substance transfers heat to another substance or object that it is in contact with. ex: handle of a frying pan getting hot bc the pan is hot

28
Q

what is convection heat transfer

A

takes place when a warm substance changes location, such as when warm air rises

29
Q

what is radiation heat transfer

A

takes place when electromagnetic waves carry energy from an energy source, ex: the sun

30
Q

what does the sensation of hot or cold depend on?

A

which direction heat is transferred

31
Q

what is thermal equilibrium?

A

when 2 objects reach the same temperature

32
Q

the first law of thermodynamics

A

states that energy is always conserved. heat is always transferred from a hotter object, to cooler. likewise you can’t create energy

33
Q

second law of thermodynamics

A

states that energy tends to disperse, or spread out. energy transfers from a hot object, to a colder object. ex: a fire, and how you can feel the heat of it far away. entropy of a system tends to increase over time.

34
Q

what is entropy

A

means that energy tends to become more dispersed and disordered rather than collected and ordered. Ex: spraying perfume, it does everywhere, you can’t get it back into the bottle

35
Q

thermal energy

A

describes the total amount of energy in the particles of a sample.

36
Q

what is the thermal energy dependent on?

A

the temp of the sample and the number of particles in the sample (mass).

37
Q

what is a calorie

A

is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius

38
Q

what is the equation used to measure heat transfer?

A

Q= (m)x(1cal/gXdegreesC)x(Temp. Initial- Temp. Final).

Use distributive property

39
Q

what is the difference between temp. and heat?

A

the temp is a measure of the avg kinetic energy of its particles. heat is a process of energy transfer to or from a sample of matter

40
Q

what is specific heat capacity ?

A

the heat required to raise the temp of 1g of a substance by 1 degree Celsius. every substance is different (aluminum pot of water)

41
Q

substances that are polar tend to have ______ capacities / what does it mean?

A

high specific heat/ means that molecules will have higher specific heat capacities than metals

42
Q

why does water have a high specific heat?

A
  • the molar mass of water is small
  • water is molecular, and has complex internal movements
  • water has hydrogen bonds, strong intermolecular `attractions
43
Q

heat of vaporization?

A

heat required to change 1 gram of a substance from a liquid into a gas

44
Q

heat of fusion

A

the heat required to change 1 gram of a substance from a solid to a liquid

45
Q

when a substance changes from a solid into a liquid, or liquid into a gas energy is transferred to ____

A

to the substance from the surroundings

46
Q

when a substance changes phase from a gas to a liquid of from a liquid to a solid, energy is transferred from the ______ to the _____

A

substance to the surroundings

47
Q

energy spread is during what process

A

exothermic

48
Q

matter spread occurs during what process

A

endothermic

49
Q

during an exothermic reaction, what is felt?

A

cold

50
Q

during an endothermic reaction what is felt?

A

heat

51
Q

endothermic is

A

gaining heat energy

52
Q

exothermic is

A

loosing energy