u1: thermodynamics

Question 1

thermodynamics

Answer 1

area of physical science concerned with studying the relationships between heat, work, temperature, and energy

Question 2

thermochemistry

Answer 2

study of energy changes, namely heat energy, associated with transformations like chemical reactions and phase changes

Question 3

3 kinds of changes in matter

Answer 3

chemical, physical, and nuclear

Question 4

physical change

Answer 4

change in the form of a substance (no chemical bonds broken)

Question 5

chemical change

Answer 5

change in chemical bonds between atoms: results in rearrangement of atoms to form new substances

Question 6

nuclear change

Answer 6

change in the protons or neutrons in an atom resulting in formation of new atoms

Question 7

major types of energy

Answer 7

• kinetic energy
• potential energy

Question 8

where is energy stored in chemicals

Answer 8

chemical bonds

Question 9

how is kinetic energy measured

Answer 9

temperature (specifically change in temperature)

Question 10

energy

Answer 10

• a property of matter and radiation which is the ability to form work
• such as: causing motion, interaction of molecules
• all matter has kinetic and potential energy

Question 11

potential energy

Answer 11

energy that is stored in an object

Question 12

kinetic energy

Answer 12

energy of motion

Question 13

two ways to transfer energy

Answer 13

• heat (Q): transfer of energy between two objects due to temperature difference
• work (w): force acting over a distance (when force acts on object and object undergoes displacement)

Question 14

temperature

Answer 14

measure of the average kinetic energy of particles

Question 15

heat

Answer 15

amount of thermal energy transferred between substances, systems, or surroundings

Question 16

endothermic

Answer 16

• energy absorbed by substance/bond/nucleus
• temperature of surroundings drops

Question 17

exothermic

Answer 17

• energy released from substance/bond/nucleus
• temperature of surroundings increases

Question 18

first law of thermodynamics

Answer 18

• energy is neither created nor destroyed but transformed and transferred
• ΔE(universe)= 0 = ΔE(system) + ΔE(surroundings)
• ΔE(surroundings) = -ΔE(system)

Question 19

enthalpy equation

Answer 19

• H = E(system) + PV
• so, ΔH = ΔE(system) + PV
• but PV at contant pressure and volume, so it’s 0
• so, ΔH = ΔE(sys) [ J or kJ ]

Question 20

second law of thermodynamics

Answer 20

when 2 objects are in contact, heat is transferred from the hotter object to the cooler object until both objects have the same temperature

Question 21

chemical systems

Answer 21

set of reactants and products being studies

Question 22

surroundings

Answer 22

all matter around system that is capable of absorbing or releasing thermal energy

Question 23

types of chemical systems

Answer 23

• open
• closed
• isolated

Question 24

open system

Answer 24

• energy and matter can be exchanged with surroundings
• e.g. cup of water

Question 25

closed system

Answer 25

- energy but not matter can be exchanged - e.g. closed bottle of water

Question 26

isolated system

Answer 26

- neither energy or matter can be exchanged with surroundings - e.g. closed thermos of water - there are no truly isolated systems

Question 27

types of nuclear changes

Answer 27

- decay - fusion - fission

Question 28

alpha decay

Answer 28

- atom (parent nucleus) gives off 2 protons and 2 neutrons - mass decreases by 4 - atomic number decreases by 2 - He and energy always a product

Question 29

beta particle

Answer 29

fast moving electron emitted from nucleus of atom undergoing radioactive decay

Question 30

beta decay

Answer 30

- neutron changes into proton and electron - nucleus has one less neutron and one more proton - mass stays same - atomic number increases by 1 - electron and energy in products

Question 31

gamma decay

Answer 31

- gamma rays aren't charged particles like alpha/beta particles - they are electromagnetic radiation w/ high frequency - excess energy emitted by unstable nuclei of new atoms formed by alpha/beta decay is called gamma rays

Question 32

gamma ray photons have energies of

Answer 32

1 x 10^12 J

Question 33

nuclear fusion

Answer 33

controlled process where two lighter atoms fused together and generate heavier atom and has aim of generating energy

Question 34

nuclear fission

Answer 34

- process where heavy nuclide splits into two or more pieces - release a lot of energy