vocab ch 6

Question 1

energy

Answer 1

the capacity to do work or cause heat flow

Question 2

law of conservation of energy

Answer 2

E can be converted from one form to another but can be neither created nor destroyed

Question 3

potential energy

Answer 3

E of position

Question 4

kinetic energy

Answer 4

E of motion of an object, dependent on the mass of the object and the square of its velocity (1/2mv2)

Question 5

heat

Answer 5

E transferred between 2 objects because of a temperature difference between them

Question 6

work

Answer 6

force acting over distance

Question 7

pathway

Answer 7

the “specific conditions” E change is NOT dependent on the pathway, work and heat are dependent on the pathway

Question 8

state function

Answer 8

a property of the system that depends only on its present state

Question 9

system

Answer 9

the reactants and products of the reaction

Question 10

surroundings

Answer 10

anything else that is not the system; the reaction container, the room etc

Question 11

exothermic

Answer 11

E flows out of the system, rxn results in the evolution of heat

Question 12

endothermic

Answer 12

rxn absorbs E from the surroundings, heat flow is into the system

Question 13

thermodynamics

Answer 13

the study of E and its interconversions

Question 14

internal energy

Answer 14

E of a system is defined as the sum of the KE and PE of all the particles of the system

Question 15

enthalpy

Answer 15

at constant pressure, the change in enthalpy = the E flow as heat
a property of a system equal to E + PV
where E = internal E of the system
P = pressure of the system
V = volume of the system

Question 16

Hess’s law

Answer 16

enthalpy is a state fn: in going from a particular set of reactants to a particular set of products, the enthalpy change is the same whether the rxn takes place in one step or a series of steps

Question 17

standard enthalpy of formation

Answer 17

the enthalpy change associated with the formation of one mole of a compound at 25*C from its elements, with all substances at their standard states at that temp

Question 18

fossil fuels

Answer 18

coal, petroleum or natural gas; consists of C based molecules derived from the decomposition of once-living organisms

Question 19

petroleum

Answer 19

mostly formed from marine organisms, a thick, dark liquid composed mostly of compounds called hydrocarbons

Question 20

natural gas

Answer 20

mostly formed from marine orgnanisms, usually associated with petroleum deposits, consists mostly of methane but also contains ethane, propane and butane

Question 21

coal

Answer 21

formed from the remains of plants

Question 22

greenhouse effect

Answer 22

a warming effect exerted by the earth’s atmosphere due to thermal E retained by absorption of infrared radiation

Question 23

syngas

Answer 23

synthetic gas, a mixture of CO and H obtained by coal gasificiation

Question 24

change in E is equal to

Answer 24

the change in the system’s internal E
q + w
where q = heat
w = work