C3 - Quantitative Chemistry Flashcards
What is the law of the conservation of mass?
No atoms are lost or made during a chemical reaction so the mass of the reactants are the same as the mass of the products.
Define relative atomic mass.
Average of the mass numbers of the different isotopes of an atom.
Also taken into account, is how common as isotope is.
Define Relative Formula Mass
Sum of all the atomic masses of all atoms in a formula.
What is Avogadro’s constant?
The number of atoms, molecules or ions in a mole of a substance. The number is 6.02 x 10^23
What is the formula that links mass, RFM and moles together? (to find the mass)
Mass = RFM x moles
What is a limiting reactant in a chemical reaction?
The reactant that is completely used up. It’s called this because it limits the amount of products.
What are the 2 equations that link concentration, mole/mass and volume together?
Concentration = mass / volume
Concentration = number of moles / volume
What is the molar volume of a gas at room temperature?
One mole of a gas at room temperature occupies 24dm^3
What is titration?
A technique for finding the concentration of a solution with a known volume, by reacting it with another solution with a known volume and concentration.
Why might you not obtain the theoretical amount of useful product in a chemical reaction?
The reaction may not go all the way to completion because it is reversible.
Product may be lost when it is separated from the reaction mixture.
Side reaction may occur.
How do you calculate percentage yield?
Actual mass / theoretical mass
What is atom economy?
A measure of the amount of starting materials that end up as useful products.
What is meant by concentration?
The number of moles of a solute in a given volume of a solution.
What is the formula for finding the atom economy?
RFM of desired product / sum of RFM of all the reactants x 100
What does a dilute acid mean?
There is a small amount of acid per unit volume.
