Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
Name two synonyms of Photodissociation. What is it? |
Photolysis or photodecomposition Breaking of a molecule using light |
|
|
Provide a mathematical equation to express the proton energy in mole of sunstance |
epsilon= (6.022*10^23)*he/lambda (j/mol) |
|
|
Provide a mathematical equation to express the proton energy in kjouls per mole. What happened to the wavelength? |
epsilon= 1.19625 * 10^5/Lambda (kj/mol) wavelength is expressed in nano meters |
|
|
What enthalpy is necessary for the photodissociation of Oxygen? |
495 kj/mol |
|
|
the required enthalpy to dissociate Carbon dioxide is 635 Kj /mol. What minimal wavelength of light is required to achieve such a feat ? |
Wavelength= 119625 kj/mol / 635 kj/mol= 188,38 nm |
|
|
What happens to a molecule that absorbs light? |
Experience a change in electron arrangement |
|
|
How would you fin the wavelength of light required to dissociate NO? |
1 Find enthalpy of formation: NO= 90.2kj/mol , N= 472.7kj/mol and O = 249.2 kj/mol 2: find enthalpy change: Product - reactants= (472.7 +249.2)-90.2= 631.7 3: aplly: 119625 kj/mol / 631.7 kj/mol=189nm |
|
|
the wavelength necessary for dissociating O3 is 1139 and smaller. Why do we still have an ozone layer in that case? |
From a light wave of 350 nm to 1139 nm light absorbtion of ozone is reallly low. |
|
|
In photodissociation, the first reaction is the following: A + hv -> A*. What are the possible outcomes after this first reaction? |
Dissociation A*: -> B1+B2 Direct reaction A*+B -> C1+C2 Fluorescence A*-> A+hv Collisional deactivation A* + M -> A+M ionization: A*-> A+ + e- |
|
|
What is the quantum yield? |
The ratio between the number of molecules of A* undergoing one of these reactions and the number of absorbed photons |
|
|
If you add the five possible reaction's quantum yield together, what result will you have? |
1 |
|
|
On what does the quantum yield notably depend on? |
The wavelength |
|
|
At what wave length does NO2 has a quantum yield of 0? |
minimum of 391nm to obtain Photo dissociation, hence any wavelength will be higher than this will have a phot dissociation |
|
|
WHat are the two factors to take into account when looking at the quantum yield? |
Absorption and maximum wavelength needed to have photo dissociation |
