Which is an example of a compound ? and why ?

water

iodine

gold

sand

Water

Explanation:

A compound can be defined as the bonding of two or more atoms, where at least two are different types of atoms. That is, they are atoms from more than one element. Water fits this definition as it is the bonding between two hydrogen atoms and one oxygen atom, with chemical formula H2O. Iodine and gold are elements and therefore are only single atoms. Sand is classified as a mixture and therefore is not the correct option.

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole