Chapter 4- Chemical Calculations Flashcards
How to work out the number of moles?
Number of moles= mass (g)/ Ar
What is Ar?
The relative atomic mass it’s just the mass number
What is relative atomic mass?
The top number of a element in the periodic table, the protons and neutrons added together.
What is the relative formula mass
In a compound such as CO2.
C has a relative atomic mass of 12
O has a relative atomic mass of 16 but there are 2 atoms so that number increases to 32
These numbers are added together and it equals 44 this is the relative formula mass
What is Mr?
The relative formula mass, the relative atomic masses added together
How to work out the mass form the mole?
Mass(g) = number of moles x Ar
How to calculate concentration
Concentration (g/dm3) = amount of solute(g)/ volume of solution (dm3)
How do you calculate the % mass of an element in a compound
Percentage mass of an
element in a compound =
Ar x number of atoms of that element/ Mr of the compound x 100
How do you find the number of moles using an equation
Number of moles= mass in grams / Mr
What is the formular triangle for calculating mole stuff
Mass on top
Number of moles bottom left
Mr bottom right
MNMr
Moles
Go over pages 123-126 before test
What is a limiting reactant
The reactant that limits the reaction and amount of stuff produced
Describe the formula triangle for concentration
Mass top
Concentration bottom left
Volume bottom right
What kind of ions will acids form in water
H+
What kind of ions will alkaline form in water
OH-
