3.3 Mole Concept and Conservation of Mass Flashcards
What is the Mole rule for calculating no. of moles?
no. of moles = mass (g) / MM
what is the Mole Rule for calculating no. of particles?
no. of particles = no. of moles * Avogadro’s constant (Na = 6.02 x 10^23)
what is Avogadro’s constant?
states that one mole of any substance contains 6.02 x 10623 particles
what words are interchangeable for particles?
- atoms (as particles is the smallest unit of an atom)
- formula units (for ionic compound)
- molecules (for covalent molecules)
define empirical formula
a formula that shows the simplest whole-number ratio of elements in the compound
define molecular formula
a formula that shows the element symbols and exact number of each type of atom in a molecular compound
what are the steps to calculate empirical formula?
- Find the mass of each element in the compound
- Calculate the moles each element in the compound (n = m/ MM)
- Divide the number of moles of each element by the smallest number of moles
- convert the numbers to whole numbers and write the formula
what are the steps to calculate molecular formula?
- Number of empirical formula in the molecule (MM of given substance/ MM of the EF)
- Number of EF in the molecule
- Molecular formula = Number of EF x atoms in the EF
- Molecular formula = C6H14
what is the formula for calculating the molecular formula?
MM = no. of empirical formula units in a molecule x atoms in the empirical formula
percentage composition of a compound formula
% by mass of an element in a compound
= (atomic mass of the element x amount of element/ MM of the compound) x 100
How does a question indicate that you are looking at a limiting reagent question?
The question provides enough information about more than one substance so that moles can be calculated.
what is the % yield formula?
% yield = (experimental yield/theoretical yield) x 100
