Age 14 to 16 Challenge Level:
First divide the numbers into groups according to whether they are
concentrations, pure numbers, or volumes.
Secondly, group the concentrations into pairs, along with the
required dilution factor. Then, divide 5ml by the dilution factor
to additionally find the volume added.
The numbers should be in groups of 4 now, with three additional
Thirdly, think which of the components added would be measured as a
number per ml, rather than a number of moles per ml. This will
assign one group of 4 numbers.
Fourthly, think which of the remaining items has a large molecular
weight, and so will only have a low molar concentration added.
Assign this group of 4 numbers.
The final two groups are hard to assign: research what the
intracellular concentration of sodium ions is, since the NaCl is
added to keep the solution isotonic.
The data should be all assigned now, and the sum of the added
volumes should be equal to one of the leftover numbers. What might
the final number represent?