(a(i))[2]
Give two major differences between the ion concentrations in the solution obtained from squid nerve cells and in human blood plasma.
(a(ii))[1]
Calculate the mass of potassium ions in 250 cm$^3$ of the solution obtained from squid nerve cells.
(b)[2]
Describe a test for sodium ions. Test and result.
(c)[1]
Deduce the molecular formula of taurine showing the numbers of carbon, hydrogen, oxygen, nitrogen and sulfur atoms.
(d)[4]
Describe how to separate a mixture of dyes using paper chromatography. Include a labelled diagram in your answer.