Quantitive Chemistry Flashcards
(12 cards)
How do you calculate the % of an element in a compound?
% element = (total mass element in compound / relative formula mass) x 100
What is the relative mass of a substance in grams known as?
Mole of a substance.
How large is the mole of a substance in particles of the substance?
6.02x10^23 particles.
How do you work out the moles of a substance?
Moles = mass of substance (grams) / relative atomic or molecular mass
How do you work out the percentage yield of a product?
% yield = (actual yield of desired product / theoretical yield of desired product) x 100
Why is the percentage yield less than 100%?
Loss of product in separation from reaction mixture.
Side reactions.
Reaction may be reversible and not go to completion.
What is the equation for mass of a substance?
Mass = moles x Mr
What is the empirical formula?
Simplest whole number ratio of atoms of each element in a compound.
What is the molecular formula?
Shows actual number of atoms of each element present in a compound.
What is water of crystallisation?
Water chemically bonded into the crystal structure.
How is % of water of crystallisation in a compound calculated?
% water of crystallisation = ((degree of hydration x Mr of water) / Mr of compound) x 100
What is thermostable decomposition?
Breakdown of a solid using a salt.
