Topic 1 - Quantitative chemistry Flashcards
(30 cards)
What is a chemical species?
An atom, a molecule or an ion
What is the mole?
The amounf of a substance which contains the same number of chemical species as there are atoms in 12g of the isotope carbon-12
What is the relative atomic mass of an element, Ar?
The average mass of an atom of the element, taking into account all its isotopes and their relative abundance, compared to one atom of carbon-12
What is the relative molecular mass, Mr?
The sum of the relative atomic masses of the atoms in the molecular formula
What is the molar mass?
The mass of one mole of a species
How is the number of moles calculated?
What is the Avogardo’s constant (L)?
The number of atoms in one mole of an element and the number of molecules in one mole of a covalent compound
Has a value of 6.02 X 1023 mol-1
How is the number of particles calculated?
N = nL
What is the empirical formula?
The ratio of the atoms of different elements in a compound. It is the molecular formula expressed as its simplest ratio
What is the molecular formula?
Shows the actual number of atoms of each element present in a molecule
What are state symbols?
Indicate the state of a substance at STP: (s), (l), (g), (aq)
What is the function of the coefficients of an equation?
They give the molar ratios of the reactant and products
What is the limiting reactant?
The reactant that determines the theoretical yield of the product
What is the theoretical yield?
The mass or amount of product produced according to the chemical equation assuming 100% reaction
What is the percentage yield?
What are the intermolecular forces for particles in solid state?
The particles are closedly packed in fixed positions. The interparticle forces restrict the movement to vibration about a fixed position → fixed shape
What are the intermolecular forces for particles in liquid state?
The particles are still relatively close together. The interparticle forces are sufficiently weak to allowe the particles to change places with each other, but their moevemnt is constrained to a fixed volume. Liquids can change shape but not volume
What are the intermolecular forces for gas particles?
The interparticle forces are negligible; they are zero for an ideal gas. The particles move freely, occupying all the space available to them. No fixed shape or volume
What is the relationship between kinetic energy and its mass and speed?
The kinetic energy depends on its mass and speed.
What is Avogadro’s hypothesis?
Equal volumes of different gases contain equal numbers of particles at the same temperature and pressure
What is the number of moles for a gas?
What is the relationship between volume and pressure of a gas?
Pressure is inversely proportional to the volume
PV = k
What is the relationship between temperature and pressure of a gas?
The pressure is proportional to the absolute temperature measured in kelvin (K)
P = kT
What is the combined gas law?
