Thermochemistry

Question 1

Energy

Answer 1

the capacity to do work or to transfer heat

Question 2

Heat

Answer 2

the flow of energy from a body at higher temperature to one at lower temperature when they are placed in thermal contact

Question 3

Work

Answer 3

the movement of an object against some force

Question 4

Kinetic Energy

Answer 4

the energy that an object possesses by virtue of its motion

Question 5

Potential Energy

Answer 5

the energy that an object possesses as a result of its composition or its position with respect to another object

Question 6

Joule

Answer 6

the SI unit of energy, 1 kg-m2/s2. A related unit is the calorie: 4.184 J = 1 cal

Question 7

Calorie

Answer 7

a unit of energy, it is the amount of energy needed to raise the temperature of 1 g of water by 1 oC from 14.5 oC to 15.5 oC. A related unit is the joule: 1 cal = 4.184 J

Question 8

System

Answer 8

in thermodynamics, the portion of the universe that we single out for study. We must be careful to state exactly what the system contains and what transfers of energy it may have with its surroundings

Question 9

Surroundings

Answer 9

in thermodynamics, everything that lies outside the system that we study

Question 10

Force

Answer 10

a push or pull

Question 11

First Law of Thermodynamics

Answer 11

a statement that energy is conserved in any process. One way to express the law is that the change in internal energy, ΔE, of a system in any process is equal to the heat, q, added to the system, plus the work, w, done on the system by its surroundings: ΔE = q + w

Question 12

Internal Energy

Answer 12

The total energy possessed by a system. When a system undergoes a change, the change in internal energy, ΔE, is defined as the heat, q, added to the system, plus the work, w, done on the system by its surroundings: ΔE = q + w

Question 13

Internal Energy Equation

Answer 13

ΔE = q + w

Question 14

Endothermic

Answer 14

a process in which a system absorbs heat from its surroundings

Question 15

Exothermic

Answer 15

a process in which a system releases heat to its surroundings

Question 16

State Function

Answer 16

a property of a system that is determined by its state or condition and not by how it got to that state; its value is fixed when temperature, pressure, composition, and physical form are specified; P, V,T, E, and H are state functions

Question 17

Enthalpy

Answer 17

a quantity defined by the relationship H = E + PV; the enthalpy change, ΔH, for a reaction that occurs at constant pressure is the heat evolved or absorbed in the reaction: ΔH = qp

Question 18

Enthalpy of Reaction

Answer 18

the enthalpy change associated with a chemical reaction

Question 19

Bomb calorimeter

Answer 19

a device for measuring the heat evolved in the combustion of a substance under constant-volume conditions

Question 20

Hess’s Law

Answer 20

the heat evolved in a given process can be expressed as the sum of the heats of several processes that, when added, yield the process of interest

Question 21

Enthalpy of formation

Answer 21

the enthalpy change that accompanies the formation of a substance from the most stable forms of its component elements

Question 22

Endothermic Reaction Graph

Answer 22

Question 23

Exothermic Reaction Graph

Answer 23