Quantitative Flashcards
Empirical Formula
Formula which shows the simplest whole number ratio of atoms of each element in a compound
Molecular Formula
Formula which shows the actual no. atoms of each element in a compound
Molar Gas Vol
Vol of one mole of gas under spec cond of temp and pressure e.g 24dm3 @ 20 degress and 1 atm
Avogadro’s Law
Equal volumes of gas under the same conditions of temp and pressure containing the same no. particles
What is equ for molar gas vol?
Moles= Vol (cm3)/ 24000
Moles= Vol (dm3)/24
What is equation for percentage yield?
Actual/ Theoretical x 100
Why are yields not 100%?
Transfer Losses
Spills and splashed will cause p to be lost
R may not be entirely complete…
1: not waited long enough
2: not mixed properly
3: r may not reach 100% compl
Not all r 100% unpure
Atom Economy
Measure of how efficiently the atoms in the r are used and converted into the desired p in a chem r
A.E Equ
Mass of desired products / total mass of products X 100
Why may a.e of < 100% be imp consid for commercial succ of process?
The closer it is to 100% A.E, the more economical for industrialist
Money costs assoc with waste disposal
How could a chem company max profits from this process?
Recycle reactants / pr not desired
What are the limits of just working out % yield for any r?
R may have high % yield but A.E is low so lots of waste
What type of r do chemists want?
High % yield
High A.E
As little waste as poss
Why is imp to use XS acid?
To make sure all r changed to p
How is H2 stopped from esc from flask?
Pour acid in first, Mg in second container, put bung on, tilt conical flask to react acid with Mg
