Answer: 
Explanation
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced combustion reaction for butane is,:

The substances that dissolves in water are called solute.
To get radius, divide the diameter into 2. 3.6÷2 = 1.8 cm
Answer: Aluminum is in group IIIA of the periodic table therefore it has three valence electrons. The symbol for aluminum is Al which will be surrounded by three dots. 2.
Explanation: