The rotten smell of a decaying animal carcass is partially due to a nitrogen-containing compound called putrescine. Elemental analysis of putrescine indicates that it consists of:
C
,

54.50
%
,

H
,

13.73
%
, and
N
,

31.77
%
. Calculate the empirical formula of putrescine.

The empirical formula is .

Explanation:

Putrescine has the elements like Carbon, Nitrogen and Hydrogen present in them. So in order to determine the empirical formula, we first have to find the number of moles present in the putrescine. As the percentage of C, H and N present in the chemical is given as 54.50%, 13.73% and 31.77%, we assume that 100 g of Putrescine is taken as sample.

Then the mass of C, H and N present in Putrescine will be 54.50 g, 13.73 g and 31.77 g.  We know that the molar mass of C is 12 g/mol, H is 1 g/mol and N is 14 g/mol.  So divide the mass with the molar mass of the respective elements to determine the number of moles of these elements present in the sample.

Similarly, the number of moles of H and N present is determined.

Then the empirical formula can be determined by dividing the number of moles of all elements with the least number of moles that is 2.27.

So, the empirical formula is .

Carbon -14 and Carbon 12 are the two substances geologists use in radiocarbon dating.

Option B

Explanation:

Radiocarbon dating denotes the determination process of the age of fossils of plants or animals based on the ratio of carbon atoms 14 to 12. Carbon naturally exists in two non-radioactive isotopes, Carbon-12 and Carbon-13 and one radioactive isotope carbon 14. The carbon 14 gets released on continuous cosmic reaction with atmospheric nitrogen.

These carbon 14 will be absorbed by the living plants and from the plants. Then, it will enter inside the animals which consume the plants. But once the plants and animals died, they ceased to intake carbon-14. In their living state, the ratios of carbon atoms 14 to 12 in them tends to similar to the ratio in atmosphere.

But after they die, the ratio of C-14 to C-12 will be varying from the ratio of C-14 to C-12 in atmosphere as the concentration of C-14 will be decreasing in the dead animals and plants. Thus using this ratio, geologists can find the fossil's age.