Final answer:
The formulae of simple compounds can be obtained experimentally by performing reactions or observations in the laboratory. Experimental methods involve analyzing the products of reactions and understanding the ratios in which atoms combine. By determining the empirical formulas, we can describe the composition of compounds.
Step-by-step explanation:
Compounds are formed when two or more elements chemically combine, resulting in the formation of bonds. For example, hydrogen and oxygen can react to form water, and sodium and chlorine can react to form table salt. We sometimes describe the composition of these compounds with an empirical formula, which indicates the types of atoms present and the simplest whole-number ratio of the number of atoms (or ions) in the compound.
For example, titanium dioxide (used as pigment in white paint and in the thick, white, blocking type of sunscreen) has an empirical formula of TiO2. This identifies the elements titanium (Ti) and oxygen (O) as the constituents of titanium dioxide, and indicates the presence of twice as many atoms of the element oxygen as atoms of the element titanium (Figure 2.19).
The formulae of simple compounds can be obtained experimentally by performing reactions or observations in the laboratory. For example, the composition of metal oxides can be determined by heating the corresponding hydroxides or carbonates and analyzing the resulting products.
Water can be obtained experimentally by the reaction of hydrogen and oxygen gases in the presence of a catalyst. Salts containing water of crystallization can be obtained by reacting metal oxides, hydroxides, or carbonates with acids or by substitution reactions involving soluble salts.
In conclusion, experimental methods can be used to determine the composition and formulae of simple compounds. These methods involve performing reactions or observations in the laboratory and analyzing the resulting products. By understanding the types of atoms present and the ratios in which they combine, we can determine the empirical formulas of compounds.