sc9, mass calculations (paper 1 and 2) Flashcards
1
Q
how to work out mass using Mr and moles
A
mass (g) = Mr x amount (mol)
2
Q
how to work out amount (moles) using number os substances and avogadros constant
A
moles = number of substances / avogadros constant
3
Q
what is avogadros constant
A
6 x 10^23
4
Q
what is the molecular formula
A
shows how many atoms are in each element of a compound
5
Q
what is the empirical formula
A
shows the simplest ratio of elements in a compounds
6
Q
why is the lid open during the detemining empitical formula practical
A
- to allow air/oxygen to react with the metal
- and also so the metal oxide doesn’t escape
