Chapter 10 and 11

Question 1

Hess’s law

Answer 1

enthalpy change for a chemical or physical reaction depends only on initial and final states

the enthalpy change is independent of the reaction pathway

Question 2

4 rules for manipulation equations in triangle H notation

Answer 2

1) when equation is flipped the sign on triangle H must be reversed
2) compounds that are on opposite sides of equation can only be cancelled out if they are in the same state
3) if the coefficients of the equation are multiplied or divided the same must be dont to their triangle H
4) compounds that are on the same sides of the equation can only be added together if they are in the same state

Question 3

steps for manipulating equations in triangle H notation

Answer 3

1) write out net equation if not given

2) manipulate equations in order to yield net equation
- flip
- multiply or divide

3) cancel out compounds on opposite sides that are same state and number
4) add remaining compounds to yield net equation

Question 4

thing to remember when multiply to manipulate an equation in triangle H notation and example

Answer 4

may have to multiply by a fraction to get the right number

Ex) have: 2H20 need: 3H20

multiply by 2/3

Question 5

Hess’s law formula

Answer 5

H reaction= the sum of nH products- the sum of nH reactants

Question 6

standard molar enthalpy of elements in standard states

Answer 6

0

Question 7

2 options for hess’s law calculations

Answer 7

triangle H (long way)

triangle H dot (short way, standard molar enthalpies)

Question 8

steps for Hess’s law calculations in triangle H

Answer 8

1) carry out steps for manipulating equations in triangle H notation
2) add the component enthalpy changes to obtain the net enthalpy change

Question 9

steps for Hess’s law calculations in triangle H dot

Answer 9

1) write out net equation if not given
2) determine unknown
3) manipulate Hess’s law formula to solve for unknown

Question 10

if H dot of something equals 0 what is it’s n value?

Answer 10

O

Question 11

exception to Hess’s law calculations in triangle H dot

why and what do to

Answer 11

if net equation has 2 or more elements

since there are no standard enthalpies of formation to plug into formula

do it as you would triangle H

Question 12

efficiency formula

Answer 12

(energy output/energy input) (100)

Question 13

What to do if Energy input/output isn’t directly given

Answer 13

use Eout or in= Qcan +Qwater

and expand to m(c)(trianglet) to solve

Question 14

scientific perspective

Answer 14

research

leads to researching and explaining natural phenomena

Question 15

technological perspective

Answer 15

technology

concerned with the development and use of machines, instruments, and processes that have a social purpose

Question 16

ecological perspective

Answer 16

environmental effects

considers relationships between living organisms and the environment

Question 17

renewable energy source

Answer 17

replenishes itself within 100 years

Question 18

non renewable energy source

Answer 18

fill in

Question 19

greenhouse gases

Answer 19

fill in

Question 20

global warming

Answer 20

fill in

Question 21

economic perspective

Answer 21

financial

gives on the production, distribution, and consumption of wealth

Question 22

political perspective

Answer 22

legislation

involves vote getting actions and measures

Question 23

what is the carbon cycle

Answer 23

storing energy in carbohydrates

Question 24

carbon cycle process

Answer 24

sun—->photosynthesis—->decay

Question 25

sun

Answer 25

fill in

Question 26

photosynthesis equation

Answer 26

6 CO2(g)+ 6 H2O(l) + energy —> C6H12O6(s) + 6 O2(g)

Question 27

cellular respiration equation

Answer 27

C6H12O6(s) + 6 O2(g) —-> 6 CO2(g) + 6 H2O(l) + energy

Question 28

how do you know a collision is effective

Answer 28

it results in a chemical reaction

Question 29

what must happen for a collision to be effective

Answer 29

1) steric factor | 2) collision must occur with enough energy

Question 30

what is steric factor

Answer 30

collision must occur with the correct geometrical alignment to bring reactive parts together

Question 31

what is steric factor important to

Answer 31

important to large molecules with large degrees of steric hindrance

Question 32

what is activation energy

Answer 32

the minimum amount of energy required for a reaction to occur

Question 33

abbreviation for activation energy

Answer 33

Ea

Question 34

activation energy with alligator

Answer 34

E>Ea

Question 35

another definition or activation energy

Answer 35

the barrier that must be overcome for a chemical reaction to occur

Question 36

what is transition state

Answer 36

the activated complex when it has Ea

Question 37

what are the factors increasing the rate of reaction

Answer 37

-increasing the # of molecules that have sufficient energy to react - properties of reactants - some reactions occur more slowly because of this - temp - catalysts

Question 38

what is temp directly related to

Answer 38

temp is directly related to the average kinetic energy in a sample

Question 39

what is maxwell boltzmann distribution used to explain

Answer 39

used to explain reaction rate and temp

Question 40

the maxwell boltzmann distribution is a plot of ______

Answer 40

#’s or particles vs. energy of particles

Question 41

wha does the maxwell boltzmann distribution show

Answer 41

shows that at diff temps many particles have energies close to the mean but there are still outliers are are at above or below the mean

Question 42

what is the area under the curve in the maxwell boltzmann distribution

Answer 42

area under the curve = total energy

Question 43

what is bond breaking and type of process

Answer 43

kinetic energy is absorbed and stored as potential energy in chemical bonds endothermic process

Question 44

what is bond making and type of process

Answer 44

chemical potential energy is released as kinetic energy exothermic process

Question 45

what is a catalyst

Answer 45

increases reaction rates by providing alternative pathways for changes without affecting the net amount of energy involved

Question 46

what does a catalyst provide

Answer 46

provides an alternative pathway that relay ire a lower activation energy than the original pathway

Question 47

potential energy diagram for exothermic reaction

Answer 47

goes up to down triangle H= from A+B down to C+D Ea foreword= from A+B to top of curve Ea reverse= from C+D to top of curve transition state=point at top of curve

Question 48

potential energy diagram for endothermic reaction

Answer 48

goes down to up triangle H= from C+D to A+B Ea forward= from A+B to top of curve Ea reverse= from C+D to top of curve transition state= point at top of curve

Question 49

what are the labels of the axis in energy diagrams

Answer 49

x= reaction pathway y= potential energy

Question 50

which way do Ea arrows always point on potential energy diagrams

Answer 50

up

Question 51

what is triangle H always in between on potential energy diagrams

Answer 51

A+ B and C+D

Question 52

what is Ea forward always inbetween on potential energy diagrams

Answer 52

A+B and curve

Question 53

what is Ea reverse always in between on potential energy diagrams

Answer 53

C+D and curve