Question

1) Cite at least two reasons why the age of rocks cannot be determined by the carbon-14 method

2) Before lead storage batteries were sealed, the condition of a battery could be determined by easuring the denssity of the sulfuric acid electrolyte solution with a hygrometer. Would a relatively low density indicate that the battery needed to be charged or that it was fully charged? Explain your answer

Answer 1

1) (i) The age of the rock determined is not close to the real value, the approximate value cannot
be known even if the decay is at constant rate it is logarthimic and hence has some limits.
(ii) The half-life period is limited and this method is only useful for carbon containing organic
compounds
(iii) Most of the times larger samples are analyzed and the new carbon might come in contact
with old carbon in sample causing contamination.

2) The specific gravity is measured using hydrometer to check for the charge in cell. Specific
gravity is the relative density of 2 compounds which in this case are sulfuric acid and water
If the density is high then the concentration will be high and hence more concentrated solution
can posses higher state of charge.