Atoms and Molec...

Which of the following correctly represents Dalton's symbols?

What is the formula mass unit of $$HCl$$ ?

What is the formula unit mass of sodium chloride?

An ion is produced as a result of gain or loss of electrons by an atom.  In $$Au^{3+}$$ ion, 3 electrons are ___________by $$Au$$ atom.

When the size of a spherical nanoparticle decreases from $$\text {30 nm}$$ to $$\text {10 nm}$$. The ratio surface area/volume becomes:

Select the smallest atom.

Which one of the following atoms will have largest size?

One sample of air is found to have 0.03% and another sample has 0.02% carbon dioxide. This illustrates that: 

$$SO_2$$ gas was prepared by
(i) burning sulphur in oxygen,
(ii) reacting sodium sulphite with dilute $$H_2SO_4$$ and
(iii) heating copper with $$conc. H_2SO_4$$. It was found that in each case sulphur and oxygen combined in the ratio of 1 : 1. The data illustrates the law of :

$$1$$ mole of a compound contains $$1$$ mole of $$C$$ and $$2$$ moles of $$O$$. The molecular weight of the compound is :