Chapter 3 Flashcards
Mole definition
The amount of substance that contains 6.02 x 10^23 particles
Avogadro constant
The number of particles in each mole of carbon -12
Molar mass
The mass per mole of a substance
G mol -1
Molecular formulae
The number of atoms of each element in a molecule
Empirical formula
The simplest whole ratio of atoms of each element in a compound
Relative molecular mass
Compares the mass of a molecule with the mass of an atom of carbon 12
Relative formula mass
Compares thé mass of a formula unit with the mass of an atom of carbon 12 - substances that don’t exist as molecules
Hydrated =
Water molecules are part of their crystalline structure
When heated bonds between water are broken Leaving white anhydrous copper (II) sulfate
Method:
Weigh empty crucible
Weigh c + hydrated salt
Heat c
Weigh c + anhydrous salt
Standard solution
Solution of known concentration
Stoichiometry
The balancing numbers that give the ratio of the amount of each substance
Theoretical yield
The maximum mass of a product that could be formed in a reaction
Percentage yield
Shows the conversion of starting materials into desired product
Factors that may affect percentage yield
- reactants may react in a different way then expected
- reaction may not go to completion
- may lose product
Limiting reagent
The reactant that is not in excess will be used up first and stop the reaction
Atom economy
A measure of how many atoms in the reactants form a desired product
Atoms with higher atom economies produce fewer waste
Molar gas volume
Volume per mole of gas molecules at stated temperature and pressure
Assumptions for ideal gas
Random motion
No intermolecular forces
Negligible size
Elastic collisions
Finding the relative molecular mass of a volatile liquid
Add sample of volatile liquid to a small syringe via needle Inject the sample into a gas syringe Rewrite the gas syringe Place gas syringe in boiling water bath Liquid vaporises producing a gas Record the pressure of the gas
