Chemical Calculations Flashcards
1
Q
How do you calculate relative atomic masses
A
(% x mass no) + (% x mass no) / 100
2
Q
How do you calculate the relative formula mass
A
Add up the relative atomic masses
Eg h2o
(2 x 1) + 16 = 18
3
Q
What is one mole
A
The amount (in g) of an element that contains 6 x 10 to the power of 23 atoms Eg 1 mole of water contains 6 x 10 to the power of 23 molecules of h2o and has a mass of 18g
4
Q
Mass =
A
Moles x relative atomic mass
Or
Moles x relative formula mass
5
Q
Moles =
A
Mass / relative atomic mass
Or
Mass / relative formula mass
6
Q
How to work out empirical formulae
A
Symbols for atoms
Ratio by mass / relative atomic mass / smallest
7
Q
How do you found the molecular formula after finding the empirical formula of something
A
Find the empirical formula mass, then find the number of times this goes into the relative formula mass
8
Q
How do you represent the amount of a substance
A
Using moles
