Which test is used to detect nitrogen, sulfur, and halogens?

The test used to detect nitrogen, sulfur, and halogens is Lassaigne's test

The Lassaigne's test also known as sodium fusion test  is used in elemental analysis for the qualitative measurements of the presence of elements such as halogens, nitrogen, and sulphur, in any  organic compound. It was developed by J. L. Lassaigne. This is done by fusing the organic compound with sodium metal. The ionic compounds formed during the fusion are taken up in aqueous solution and can be detected by simple chemical tests taken in laboratory.

mechanics (greek   is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. the scientific discipline has its origins in ancient greece with the writings of aristotle and archimedes[1][2][3] (see history of classical mechanics and timeline of classical mechanics). during the early modern period, scientists such as galileo, kepler, and newton laid the foundation for what is now known as classical mechanics. it is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. it can also be defined as a branch of science which deals with the motion of and forces on objects. the field is yet less widely understood in terms of quantum theory.

explanation:

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3