Chapter 1-Stoich Flashcards
The # of substances in a mole.
6.02*10^23 (Avogadro’s constant)
The number of moles (using # of particles)
n=number of particles/6.02*10^23
Molecular formula of compounds indicates?
- The elements present in compound
2. The actual # of atoms of these elements in 1 molecule
Percentage yield?
Actual yield/theoretical yield
Atom economy?
mass of atoms in desired product/mass of atoms is reactants.
Amt of gas at same temp and pressure occupy the same?
Volume
Amt of gas?
Volume of gas (V stp)/Molar volume of gas (22.7 dm^3)
[Volume of gas at at 273K and 100KPa in dm^3 a]
Ideal Gas equation
PV=nRT
R=Ideal gas constant=8.31 J/K mol
Ideal Gas equation conditions
There are NO attractive forces between particles
Kinetic energy of particles=directly proportional to Abs Temp.
Double temp, what happens to volume if Pressure is constant?
Double volume
Double temp, what happens to pressure if Volume is constant?
Double pressue
Boyle’s Law
P1V1=P2V2
Dilution Calculations
C1V1=C2V2
When to use Back titration?
Used when reactions occur too SLOWLY for titration to be carried out.
e.g: When insoluble solid reagents used
Steps of Back titration?
- Sample (e.g insoluble base) reacted with known excess of 1 reagent (e.g known Vol of standard soln of acid)
- When reaction complete = titrated (e.g with alkali of known conc.) to determine how much of reagnet in excess remains unreacted.
- Know initial amt of reagent and the amt remaining as excess THEN amt that has reacted with sample can be calced.
- The total amt of acid (known) must be sum of amt that reacted with alkali (known) and the amt that reacted with sample (unknown) so latter can be calced.
