Since the atmospheric pressure at Mt Everest is constant, the process will take place at constant pressure and such process at constant pressure is called Isobaric process. Hope this helps!
The given question is incomplete. the complete question is:
The world burns the fossil fuel equivalent of approximately
kg of petroleum per year. Assume that all of this petroleum is in the form of octane. Calculate how much CO2 in kilograms is produced by world fossil fuel combustion per year.( Hint: Begin by writing a balanced equation for the combustion of octane.)
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.

To calculate the moles :

According to stoichiometry :
As 2 moles of octane give = 16 moles of 
Thus
of octane give =
of 
Mass of 
Thus
of
is produced by world fossil fuel combustion per year.
Make sure that you understand what they are asking you from this question, as it can be confusing, but the solution is quite simple. They are stating that they want you to calculate the final concentration of 6.0M HCl once a dilution has been made from 2.0 mL to 500.0 mL. They have given us three values, the initial concentration, initial volume and the final volume. So, we are able to employ the following equation:
C1V1 = C2V2
(6.0M)(2.0mL) = C2(500.0mL)
Therefore, the final concentration, C2 = 0.024M.
Isotopes of the same element
₃₅⁷⁷X and ₃₅⁸¹X
<h3>Further explanation</h3>
Given
Isotopes of element
Required
Isotopes of the same element
Solution
The elements in nature have several types of isotopes
Isotopes are elements that have the same Atomic Number (Proton) and different mass numbers
Element symbols that meet the 2 conditions above are :
₃₅⁷⁷X and ₃₅⁸¹X