Unit 2 Flashcards
How do you get from g/dm^-3 to mol/dm^-3?
Mass = moles x Mr
Therefore, moles = Mass/Mr
How do you get from mol/dm^-3 to g/dm^-3?
Mass = moles x Mr
What is the equation you would use to find an unknown volume or concentration, assuming you were given 3 already and had to find the 4th?
MV (substance A) moles of A
_____________ = __________
MV (substance B) moles of B
M = Molarity V = Volume
What is the equation for percentage uncertainty?
Percentage = (uncertainty/reading) x 100
What are two indicators used in Titrations?
Methyl Orange and Phenolphthalein
When adding acid to alkali, what colour changes do both indicators endure?
Methyl Orange: yellow - red
Phenolphthalein: red - colourless
Why is Universal Indicator not used for Titrations?
The colour change is too gradual.
What is ozone?
O3
Where is the ozone layer?
In the stratosphere.
Write the equation(s) to show how ozone is destroyed by chlorine free radicals.
Cl@ + O3 —> O2 + ClO@
ClO@ + O3 —> 2O2 + Cl@
How do chlorine free radicals form?
CFCs are broken down by ultraviolet (UV) radiation to form chlorine free radicals.
Which bond in CFCs are broken when chlorine free radicals are formed?
Carbon-chlorine bonds.
Why are chlorine free radicals an example of a catalyst during the reaction in which they break down ozone?
The free radicals stay in the same form throughout the reaction - they are not used up and do not change.
What other free radical can damage the ozone layer?
Nitric oxide.
Where do nitric oxide free radicals come from?
Nitrogen dioxide.