What do + and → mean, in an equation?

This represents a chemical equation of a reaction. This means that reactants react and form products. The reactants are written on LHS and products are written on RHS, and these are separated by an arrow mark. The reactants and products are written using the chemical symbols. The state of their matter is also written within the brackets. For example, Carbon reacts with Oxygen to form carbon dioxide. C s + O 2 g → CO 2 g

Balance the following equation: Na s + Cl 2 g → NaCl s

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. Sodium metal reacts with Chlorine gas to form Sodium chloride. 2 Na s + Cl 2 g → 2 NaCl s

Balance the following equation: H 2 g + I 2 g → HI g

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. Hydrogen gas reacts with Iodine gas to form Hydrogen iodide gas H 2 g + I 2 g → 2 HI g

Balance the following equation: Na s + H 2 O l → NaOH aq + H 2 g

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. When Sodium metal is added to water, Sodium hydroxide and Hydrogen gas is formed. The reaction is very vigorous and the reaction mixture catches fire. 2 Na s + 2 H 2 O l → 2 NaOH aq + H 2 g

Balance the following equation: NH 3 g → N 2 g + H 2 g

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. Ammonia gas undergoes decomposition to form Nitrogen gas and Hydrogen gas. This reaction is slightly endothermic as it absorbs heat form the surrounding. 2 NH 3 g → N 2 g + 3 H 2 g

Balance the following equation: C s + O 2 g → CO g

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. Carbon undergoes incomplete combustion to form Carbon monoxide. 2 C s + O 2 g → 2 CO g

Balance the following equation: Al s + O 2 g → Al 2 O 3 s

A chemical equation is said to be balanced when number of atoms of elements of reactants and products are equal. This follows law of conservation of mass. Aluminium metal undergo oxidation to form Aluminium oxide. This is observed in aluminium vessels which acquires a thin black coating after sometime. 4 Al s + 3 O 2 g → 2 Al 2 O 3 s