Some Basic Conc...

Who supported the Four Element Concept of Empedocles?

Radioactivity is the caused by the disintegration of:

A compound $$X_2O_3$$ contains 31.58% oxygen by weight. The atomic weight of $$X$$ is:

At room temperature and pressure, two flasks of equal volumes are filled with $$H_2$$ and $$SO_2$$ separately. Particles which are equal in number, in the two flasks are:

What is the mass of one molecule of yellow phosphorus? 

$$SO_2$$ 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 :

2.0 g mixture of sodium carbonate and sodium bicarbonate on heating to constant mass gave 224 mL of $$CO_2$$ at NTP. The % mass of sodium bicarbonate in the mixture is: 

Cations absorb $$6.023\times 10^{22}$$ electrons for their reduction. How many equivalents of the ion are reduced?

The father of modern chemistry is:

Hydrogen combines with chlorine to form HCI. It also combines with sodium to form NaH. If sodium and chlorine also combine with each other, they will do so in the ratio of their masses as: