Chapter 5

Question 1

What is the equation to find Electrostatic Potential energy?

Answer 1

Eel= kQ1Q2/d

Question 2

What is zero electrostatic potential energy?

Answer 2

as the potential energy at infinite speration of the charged particles.

Question 3

When Q1 and Q2 have the same sign what happens to the particles?

Answer 3

they repel each other and a repulsive forces pushes them apart

Question 4

How do you bring two postiviely charged objects closer?

Answer 4

you have to do work to overcome the repulsive force that exists between the two

Question 5

What does the potential energy do as Electrostatic energy is postive?

Answer 5

deceares

Question 6

What does distance do as potential energy decreases?

Answer 6

increase

Question 7

What happens when Q1 and Q2 have opposite signs?

Answer 7

the particles attract each other and an attractive force pulls them toward each other

Question 8

When is Electrostatic potential energy negative?

Answer 8

when the charges have opposite signs

Question 9

What does the potential energy do as Electrostatic enrgy is negative

Answer 9

increases

Question 10

What does distance do as potential energy increases?

Answer 10

decrease

Question 11

How is energy released?

Answer 11

chemical bonds are formed

Question 12

How is energy consumed?

Answer 12

chemical bonds are broken

Question 13

What is the first law of thermodynamics?

Answer 13

energy can be converted from one from to another, but it is neither created nor destroyed

Question 14

What is the equation to find internal energy?∆E

Answer 14

∆E= q+w

Question 15

What is the system?

Answer 15

the portion of the unvierse that we single out for study

Question 16

What is the surroundings?

Answer 16

everything that lies outside teh system that we study

Question 17

What is an open system?

Answer 17

one in which matter and energy can be exchanged with the surroundings

Ex:an uncovered pot of boiling water on a stove

Question 18

What is a closed system?

Answer 18

exchange energy but not matter with its surroundings

Ex:a mixture of hydrogen gas, and oxygen gas in a cylinder fitted with a piston

Question 19

What is an isolated system?

Answer 19

neither energy nor matter can be exchanged with the surroundings

Ex: an insulated thermos containing hot coffee

Question 20

What is internal energy?

Answer 20

the sum of all the kinetic and potnetial energies of the componetns of the system

Question 21

What does a -∆E mean?

Answer 21

lost energy to its surroundings

Question 22

What does a +∆E mean?

Answer 22

gained energy from its surroundings

Question 23

What causes ther maginuted of internal energy(∆E) to change?

Answer 23

the adding and removing of heat or as work is done on or by the system

Question 24

When heat is added to a system do the ∆E increase or decrease?

Answer 24

increases

Question 25

When work is done on a system does ∆E increase or decrease?

Answer 25

increases

Question 26

When does q or heat have a postive value?

Answer 26

when heat is transferred to the system from the surroundings

Question 27

When does w(work) have a postive value?

Answer 27

when work is done on the system by the surroundings

Question 28

When heat is lost by the system does ∆E increase or decrease?

Answer 28

decrease

Question 29

When work is done by the system on the surroundings does ∆E increase or decrease?

Answer 29

decrease

Question 30

When does w(work) have a negative value?

Answer 30

when work is done by the system on the surroundings

Question 31

When does q(heat) have a negative value?

Answer 31

heat lost by the system to the surroiundings

Question 32

When is a process endothermic?

Answer 32

system absorbs heat from its surroundings

Question 33

When is a process exothermic?

Answer 33

system loses heat

Question 34

What influences internal energy of a system?

Answer 34

temperature and pressure

Question 35

What is a state function?

Answer 35

a property of a system that is determined by its state or condition and not by how it got to that state

Question 36

What are examples of state functions?

Answer 36

Tempature, pressure, composition

Question 37

What kind of a function is ∆E?

Answer 37

state function

Question 38

What kind of a function is q?

Answer 38

path function

Question 39

What kind of function is w?

Answer 39

path function

Question 40

What is ∆H?(change in enthalpy)

Answer 40

a reaction that occurs at constant pressure is the heat evolved or absorbed in the reaction

Question 41

How do you find enthalpy?(H)

Answer 41

E+PV

Question 42

What is pressure-volume work?

Answer 42

work perfomed by exapnsion of a gas against a resisting pressure

Question 43

What is the equation for volume-pressure work?

Answer 43

w=-P∆V

Question 44

When is pressure volume work positive?

Answer 44

when ∆V is negative, work done on the system by surroundings

Question 45

when is the pressure volume work negative?

Answer 45

∆V is positive, system does work on teh surroundings

Question 46

How many J is in 1L-atm?

Answer 46

101.3J

Question 47

What is the equation for ∆H(change in enthalpy)?

Answer 47

∆H= ∆E+P∆V

Question 48

What is ∆H= to?

Answer 48

q(heat of system at constant pressure)

Question 49

when ∆H(change in enthalpy) is positive what is q?

Answer 49

the system has gained heat from the surroundings so also postivie

Question 50

When ∆H( change in enthalpy) is negative what is q(heat)?

Answer 50

the system released heat to the surroundings(-)

Question 51

When ∆H is positive and q is postive is endothermic or exothermic?

Answer 51

endothermic

Question 52

When ∆H is negative and q is negative is it endothermic or exothermic?

Answer 52

exothermic

Question 53

Is ∆H a state or path function?

Answer 53

state function

Question 54

What is the ∆H for a chemical reaction?

Answer 54

∆H=Hproducts- Hreactants

Question 55

What is enthalpy of reaction?

Answer 55

the enthalpy change associated with a chemical reaction

Question 56

How is enthalpy of reaction written?

Answer 56

∆Hrxn

Question 57

Is enthalpy a extensive or intensive proerpty?

Answer 57

extensive property

Question 58

What is ∆H proportional to?

Answer 58

the amount of reactant consumed in the process

Question 59

What happens to the ∆H when you reverse the reaction?

Answer 59

the signs flip

Question 60

What does the ∆Hrxn depend on?

Answer 60

states of the reactants and products

Question 61

How to find heat(q) when given g of a reactant and the chemcial formula and the ∆H

Answer 61

Convert g to moles use the moles in chemical equation times the ∆H

Question 62

What is calorimetry?

Answer 62

the experimental measurement of heat produced in chemical and physical processes

Question 63

What is caloriemter?

Answer 63

an apparatus that measrues the heat released or absorbed in a chemical or physical process

Question 64

What is heat capacity?

Answer 64

the quantity of heat required to raise the temperature of a sample of matter

Question 65

What is molar heat capactiy?

Answer 65

the heat required to raise the temperature of one mole of a substance

Question 66

What is specifc heat?

Answer 66

the heat capacity of 1g of a substance the heat required to raise the temperature of 1g of a substance by 1 degree celsisus

Question 67

How can you find specifc heat(Cs)?

Answer 67

q(heat)/m x ∆T

Question 68

What is the units of Cs(specific heat)?

Answer 68

J/g-K

Question 69

How do you find q(heat)?

Answer 69

q=Cs(specific heat) x m x ∆ T

Question 71

What is constant-pressure calorimetry?

Answer 71

monitoring the temp of the solution, we are seeing the flow of heat between teh system and the surroundings

Question 72

When does the tempature rise in constant pressure calorimetry?

Answer 72

heat is lost by the reaction and gained by the water in the solution(exothermic reaction)

Question 73

When is tempature decreased?

Answer 73

heat is gained by the reaction and lost by the water in teh solution

Question 74

What is the heat of the solution=?(qsoln)

Answer 74

-heat of reaction(-qrxn)

Question 75

When ∆T is positive what is qrxn?

Answer 75

negative

Question 76

What is a bomb calorimeter?

Answer 76

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

Question 78

What is the qrxn for a bomb calorimeter?

Answer 78

qrxn=-Ccal x ∆T

Question 79

What is Hess's law?

Answer 79

if a reaction is carried out in a seried of stpes, ∆H for the overall reaction equals the sum of the enthalpy changes for the steps

Question 80

What is enthalpy of formation?

Answer 80

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

Question 81

How do you find enthalpy of formation? (∆H˚f)

Answer 81

wanting to find the a compound of something by getting one mole of it

Question 82

How to find enthalpy formation of a reaction?(∆H˚rxn )

Answer 82

∑n∆H˚f(products)-∑m∆H˚f(reactants)

Question 83

What is the ∆H˚rxn for decomposition?

Answer 83

the reverse of the formation reaction

Question 84

What is bond enthalpy?

Answer 84

the enthalpy change, ∆H required to break a particular bond when the substance is in the gas phase

Question 85

How to find ∆Hrxn(for bonds)?

Answer 85

∑(bond enthalpies of bonds broken)-∑Bond enthalpies of bonds formed)