my ques ok a coumpond containing 3atoms of carbon an 8 atoms ofhydrogen combined in reaction with oxy molecules the two end products of this equation are carbon dioxide co2 an water wat element should i look at first in balancing this question and wen i hav finished balancing this qestion wich chemical or element will hav the largaest no of molecules in this equation help pleese

You are talking about the combustion of propane (C3H8).

The reaction that takes place is

C3H8 + 5 O2 -> 3 CO2 + 4H2O

The chemical with the most molecules per reaction is O2.

To balance the chemical equation and identify the element to start with, you want to ensure that there is an equal number of atoms for each element on both sides of the equation. In this case, we have carbon (C), hydrogen (H), and oxygen (O).

To balance this equation, follow these steps:

1. Start by counting the number of atoms on each side of the equation.
On the reactant side, we have:
C: 3 atoms
H: 8 atoms
O: 0 atoms

On the product side, we have:
C: 1 atom
H: 2 atoms
O: 3 atoms

2. Begin balancing with the element that appears in the least number of molecules or atoms in the unbalanced equation. In this case, hydrogen (H) has the least number of atoms.

3. To balance hydrogen, you need to equalize the number of hydrogen atoms on both sides of the equation. Since there are 8 hydrogen atoms on the reactant side and 2 on the product side, you need to add a coefficient to the product side to balance it. Thus, multiply water (H2O) on the product side by 4, resulting in 4H2O.

The balanced equation becomes:

C3H8 + O2 → 3CO2 + 4H2O

Now, to answer your second question regarding which element or compound will have the largest number of molecules in the equation after balancing, you should look at the coefficients in front of the compounds. In this case, carbon dioxide (CO2) has a coefficient of 3, indicating that it will have the largest number of molecules.