EL.6 Flashcards
Ar, Mr, percentage yield, and balancing equations
What is molar mass?
The mass of one mole of substance (element/compound).
How to you calculate the number of moles?
number of moles n (mol) = mass m (g) / relative molecular mass Mr (g/mol)
What are formula units?
The basic building blocks that match the formulae of the substance, it can be single atoms, molecules, or groups of ions.
What is the constant number of formula units in one mole of substance called?
The Avogadro constant.
What is the molecular formula of a molecule?
The actual numbers of different types of atoms in the molecule.
What is the empirical formula of a molecule?
The simplest ratio of the different types of atoms in the molecule.
Which type of formula would you get from doing a percentage mass calculation?
Empirical formula.
What information do you need to convert the empirical formula of a molecule into its actual molecular formula?
The molecular mass.
What is water of crystallization?
When molecules of water is trapped in crystals of ionic lattices in a regular manner.
What are these crystals with water trapped inside said to be?
They are hydrated.
How can water of crystallization be removed from hydrated crystals?
Heat the hydrated crystal, and the water will be removed as steam.
What is the crystal said to be when water is removed?
Anhydrous.
What is theoretical yield?
The expected amount of product in a reaction carried out under ideal conditions.
What are the factors that reduce the yield of product produced in reality?
- Loss of products from reaction vessels, particularly if there are several stages to the reaction.
- Side reactions occurring, producing unwanted by-products.
- Impurities in the reactants.
- Changes in temperature and pressure.
- If the reaction is an equilibrium system.
What is the reduced amount of products we tend to get in reality known as?
Experimental yield.
