Number
of moles of a substance =
|
mass
of substance in grams
|
relative
atomic or formula mass
|
Concentration
of solution, mol dm-3 =
|
number
of moles of solute
|
volume
of solution in dm3
|
Relative atomic
masses: H = 1, C = 12, O = 16, Na = 23, Mg = 24, Ca = 40, Br = 80, Ag =
108, Au = 197
1 The number of moles of atoms in 12g of
carbon and 108g of silver are the same. Explain this statement.
2 A pure gold wedding ring weighs 4g. How many
moles of gold atoms are there in the ring?
3 The ingredients label on a packet of salted
crisps says that it contains 0.23g of sodium. How many moles of sodium ions
does this represent?
4 What is the mass of 2 moles of calcium
carbonate?
5 A 0.75 dm3 bottle of ginger beer
contains 14.1g of sucrose, C12H22O11.
a What is the relative formula mass of the sucrose?
b How many moles of sucrose are in the ginger
beer?
c What is the concentration of the sucrose
in the ginger beer in mol dm–?
Extra challenge
6 A sample of magnesium bromide (MgBr2)
weighs 46g. How many moles of magnesium ions and bromide ions are in the
sample?
Make a poster in which you are showing the rock cycle. Include all key words and processes you can think of and any bit of relevant research. For next Wednesday 23rd.