3: Quantitative Chemistry Flashcards
What is the equation for concentration?
Concentration = mass or moles over volume
How can the concentration of a solution be changed?
-Increased by dissolving more solute in a given volume of solution (increases mass)
-Increased by allowing some of the solvent to evaporate (decreases volume of solution)
What is the mole?
The amount of substance that contains Avogadro’s constant number of particles.
What is the mass of one mole of a substance equal to?
The relative atomic mass of its formula in grams (Mr or Ar)
What number is Avogadro’s constant?
6.02 times 10 to the power of 23
How do you calculate the amount of a given mass in moles? (The equation)
Moles = mass/relative atomic or formula mass
If there is reactant left over after a reaction, what is it described as?
Being in excess
How do you calculate atom economy?
(Total Mr of the desired product / Total Mr of all the reactants) x 100
How do you calculate percentage yield?
(Mass of product actually made / Maximum theoretical mass of product) x 100
What factors does the pathway chosen for a product depend on?
-Percentage yield
-Atom economy
-Rate of reaction
-Equilibrium position
-Usefulness of by-products
What is avogadro’s law?
At a given temperature and pressure, equal volumes of different gases contain an equal number of molecules.
What is molar volume?
The volume occupied by one mole of any gas at room temperature and pressure. 24dm^3
