thermochemistry (unit a)

Question 1

spontaneous

Answer 1

something inclined to happen
-driven toward the end

Question 2

potential energy

Answer 2

stored energy

Question 3

kinetic energy

Answer 3

energy of motion
-movement
-temperature

Question 4

kelvin equivalent to celcius

Answer 4

0C=273.15K

Question 5

changes in motion correspond with changes in

Answer 5

kinetic energy

Question 6

entropy

Answer 6

measure of disorder in a system
-randomness and speed

Question 7

increased entropy factors

Answer 7

-increase in moles of gas molecules
-state changes
-increase in temperature
generally more motion

Question 8

kinetic molecular theory

Answer 8

moving particles will interact more or less strongly with each other
-depending on the states
-motion inc as temp inc

Question 9

temperature increase affects motion…

Answer 9

motion increases

Question 10

temperature

Answer 10

measure of average kinetic energy of the particles of a system

Question 11

heat

Answer 11

transfer of thermal energy between two systems

Question 12

where is potential energy stored

Answer 12

within bonds between molecules and within molecules

Question 13

energy is ____ to break bonds

Answer 13

required

Question 14

energy is ____ when bonds are formed

Answer 14

released

Question 15

enthalpy change

Answer 15

basis of all change due to energy transformation

Question 16

simple example of enthalpy change

Answer 16

solar energy - glucose - hydrocarbons

Question 17

second law of thermodynamics

Answer 17

heat will flow from a high to low until thermal equilibrium is reached
-warm cup of tea

Question 18

how exactly does heat transfer

Answer 18

as particles collide they transfer energy via conduction until all paarticles have the same kinetic energy

Question 19

kinetic energy calculation FORMULA

Answer 19

Q= mcΔt

Question 20

specific heat

Answer 20

amount of energy required/released when one kilogram of the substance is raised or changes in temperature by one degree

Question 21

when is Q positive

Answer 21

energy is being released from system
-exothermic
-Δt is also positive

Question 22

when is Q negative

Answer 22

energy is being absorbed from surroundings
-endothermic
-Δt is negative

Question 23

endothermic reaction

Answer 23

absorgbs energy from surroundings
-reactants has less potential than products
-ΔH is (+)

Question 24

energy has been put into the reaction

Answer 24

endothermic

Question 25

exothermic reaction

Answer 25

energy is being released to surroundings -reactants has more potential than products -ΔH is (-)

Question 26

something that is endothermic in one direction will be _____ in the other direction

Answer 26

exothermic

Question 27

collision theory

Answer 27

in order for a reaction to happen -molecules must collide -in proper orientation -minimum amount of energy (activation energy)

Question 28

activation energy

Answer 28

minimum amount of energy required to initiate reaction -increase frequency of collisions

Question 29

factors of a faster reaction

Answer 29

increased collisions -increased concentration -increased temperature -increased surface area (solid)

Question 30

activated complex

Answer 30

temporary chemical species, temporarily formed by reactant molecules as a result of collision -prior to product

Question 31

breaking bonds

Answer 31

absorbs energy -endothermic bonded particle + energy --> seperate particle

Question 32

making bonds

Answer 32

releases particles -exothermic seperate particles ---> bonded particle + energy

Question 33

catalysts

Answer 33

changes the rate of reaction without being used up -same amount of particle -lowers activation energy -doesn't alter enthalpy change

Question 34

potential energy of the reactants and particles is ____ with or without a catalyst

Answer 34

the same

Question 35

enthalpy change

Answer 35

the difference between enthalpies of the products and the enthalpies of the reactants -total energy change for a chemical reaction

Question 36

molar enthalpy change

Answer 36

the enthalpy change per one mole of any substance involved in the chemical reaction -porportions that react

Question 37

calorimeter

Answer 37

device used to measure energy changes in a chemical reaction, results in temperature change

Question 38

exothermic calorimeter

Answer 38

increase kinetic energy of the water -inc temperature

Question 39

endothermic calorimeter

Answer 39

decrease kinetic energy of the water -decrease temp

Question 40

assumptions of calorimeters

Answer 40

there is no energy lost -same amount absorbed and released

Question 41

first law of thermodynamics

Answer 41

energy can be transferred or change form -cannot be created or destroyed

Question 42

second law of thermodynamics

Answer 42

energy flows from high regions to low until equilibrium is established

Question 43

four calorimeter assumptions

Answer 43

1. heat is not lost (isolated) 2. heat not absorbed by calorimeter 3. specific heat capacity is water 4. reactions take place at constant pressure

Question 44

heat capacity

Answer 44

-heat required to raise temperature of an object by one degree celcius -no mass

Question 45

Hess law

Answer 45

principal of addivity of reaction traits that are not able to be experimentally determined

Question 46

formation reaction

Answer 46

assemblying a compound from its elements

Question 47

decomposition reaction

Answer 47

dissassemblying a compoound into its elements

Question 48

hess law formula

Answer 48

sum of products - sum of reactants

Question 49

efficiency

Answer 49

actual divided by theoretical output divided by input