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 difference in pressure is <u>8.98 %.</u>
What is pressure ?
In the physical sciences, pressure is defined as the stress at a point within a confined fluid or the perpendicular force per unit area. A 42-pound box with a bottom area of 84 square inches will impose pressure on a surface equal to the force divided by the area it is applied to, or half a pound per square inch. Atmospheric pressure, which is roughly 15 pounds per square inch at sea level, is the weight of the atmosphere pressing down on each unit area of the Earth's surface. Pascals are used to express pressure in SI units; one pascal is equivalent to one newton per square meter. Almost 100,000 pascals of atmospheric pressure are present.
Learn more about the pressure with the help of the given link:
brainly.com/question/23603188
#SPJ4
It would be Atom 2 because the proton and neutron are both nine and the election is 8 which is -1 to nine <span />