1) There will be 5 questions which I will attempt to answer.

C3H8 + O2 → CO2 + H20 → C3H8 + 5O2 > 3CO2 + 4H2O

Al2(SO3)3 + NaOH → Na2SO3 + Al(OH)3 → Al2(SO3)3 + 6NaOH = 3Na2SO3 + 2Al(OH)3

Al2O3 + Fe → Fe3O4 + Al → 4Al2O3 + 9Fe = 3Fe3O4 + 8Al

KClO3 → KCl + O2→ 2KClO3 → 2KCl + 3O2

NH4NO3 → N2O + H2O → NH4NO3 → N2O + 2H2O

The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

The periodic table is an arrangement of the chemical elements, ordered by their atomic number (number of protons), electron configurations, and recurring chemical properties. This ordering shows periodic trends, such as elements with similar behaviour in the same column. It also shows four rectangular blocks with some approximately similar chemical properties. In general, within one row (period) the elements are metals on the left, and non-metals on the right.

Lavoisier’s Traité Élémentaire de Chimie (Elementary Treatise of Chemistry), first translated into English by the writer Robert Kerr, is considered to be the first modern textbook about chemistry. It contained a list of “simple substances” that Lavoisier believed could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc and sulfur, which formed the basis for the modern list of elements. Lavoisier’s list also included ‘light’ and ‘caloric’, which were at the time were believed to be material substances. He has classified these substances into metals and non metals.

Dmitri Mendeleev published in 1869 the first widely recognised periodic table. He developed his table to illustrate periodic trends in the properties of the then-known elements. Mendeleev also predicted some properties of then-unknown elements that would be expected to fill gaps in this table. Most of his predictions were proved correct when the elements in question were subsequently discovered. Mendeleev’s periodic table has since been expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behaviour.