24 terms

# Quantitative chemistry

Quantitative chemistry Atomic structure Periodicity Bonding Energetics Kinetics Equilibrium Acids and bases Oxidation and reduction Organic chemistry Measurement and data processing
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Define the mole and its formula:
A measure of the number of particles in a substance in comparison to the number of atoms in 12 grams of carbon-12.
n = m/M
n = Cv
Determine the number of particles
and the amount of substance (in
moles).
Number of Particles (N) = number of moles (n) x Avogadro's Constant (L)
N=nL
Define relative atomic mass (Ar):
The weighted mean of the masses of the naturally occurring isotopes of an element on a scale in which the mass of an atom of carbon-12 is taken to be 12 exactly. Symbol: Ar (the r is in subscript)
What does the term molar mass mean?
The mass of one mole of a substance. Symbol: M (in italics); unit: g mol⁻¹
Difference between the terms
empirical formula and molecular
formula?
Empirical: The lowest whole number ratio of elements in a compound.
Molecular: A formula that shows the actual number of atoms of each element present in one molecule of a compound.
How can you determine the empirical formula from
the percentage composition or from
other experimental data?
Find the percentage composition: the amount of each element in a compound expressed as a percentage.
And go through steps...
How do you determine the molecular formula
when given both the empirical
formula and experimental data?
Find the mass of empirical formula, and then divide the experimental data by this, and then times the empirical formula by the result of division.
How do you deduce chemical equations when all
reactants and products are given?
Law of conversation of mass: Mass of reactants= mass of products.
What is it important to do when writing an equation?
The mole ration, ensuring subscripts are not confused with co-efficients, using state of elements i.e. (aq), (g), (s), (l)
How do you calculate theoretical yields from
chemical equations?
Theo: The amount of product that is expected to be produced in a reaction, based on 100% reaction of the reactants.
Given a chemical equation and the mass or moles of one species how do you calculate the mass or moles of another species?
Use the molar ratio, and n = m/M
How can you determine the limiting reactant and
the reactant in excess when quantities
of reacting substances are given?
The limiting is the one which is used up completely in a reaction, while the one in excess is the one that has left over stuff.
How can you solve problems involving theoretical,
experimental and percentage yield?
Theo: The amount of product that is expected to be produced in a reaction, based on 100% reaction of the reactants.

%: A calculation of the experimental yield as a percentage of the theoretical yield.

Exper: The amount of product produced in experiment.
How do you apply Avogadro's law to calculate
reacting volumes of gases?
Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.
What is molar volume:
in general
at standard temperature and pressure
The volume occupied by one mole of a gas under a given set of conditions of temperature and pressure.
The molar volume of an ideal gas under standard
conditions is 2.24 × 10⁻² m³ mol⁻¹ (22.4 dm³ mol⁻¹ ).
What is the relationship between temperature,
pressure and volume for a fixed mass
of an ideal gas?
PV = nRT
What are the units for each of the ideal gas factors?
P is the pressure of the gas (in atmospheres, ATM)
V is the volume of the container (in dm³)
n is the number of moles of gas in the container (in mol)
R is Universal Gas Constant which is 0.0821 sm³ ATM K⁻¹ · mol⁻¹
T is the temperature of the gas (in K)
Define the term solvent:
A substance, usually a liquid, that is able to dissolve another substance, the solute.
Define the term solution:
A homogenous mixture of a solute in a solvent.
Define the term concentration:
the amount of solute per amount of solvent
What is the molar ration?
The ratio in whcih reactants and products in a chemical equation react; indicated by the coefficients written in front of each of the reactants and products in the equation.
Define relative molecular mass (Mr):
The sum of the relative atomic masses of the elements as given in the molecular formula of a compound.
What is STP:
Standard temperature and pressure: A set of conditions applied to gaseous calculations where the temperature is 0 degrees Celsius and the pressure is 1 atm (101.3 kPa).