As with any combustion reaction, the products of combusting a hydrocarbon fuel (cxhy) with oxygen (o2) are carbon dioxide (co2) and water (h2o).

a mass of 15.51 g for an unknown fuel was combusted in a reaction vessel containing an unknown amount of oxygen. at the end of the reaction, there still remained 15.46 g of the fuel as well as 0.0817 g of water and 0.1497 g of carbon dioxide. the oxygen was completely consumed during the reaction.

how many molecules of oxygen gas were initially present in the reaction vessel?

The number of oxygen gas molecules initially present are

Explanation:

The balanced chemical reaction for the combustion of given hydrocarbon follows:

To calculate the number of moles, we use the equation:

Given mass of carbon dioxide = 0.1497 g

Molar mass of carbon dioxide = 44 g/mol

Putting values in above equation, we get:

Thus,

Given mass of water = 0.0817 g

Molar mass of water = 18 g/mol

Putting values in above equation, we get:

Thus,

To calculate the number of moles of oxygen, we solve the equation for its coefficient by putting values of 'x' and 'y', we get:

According to mole concept:

1 mole of a compound contains number of molecules.

So, moles of oxygen will contain = molecules.

Hence, the number of oxygen gas molecules initially present are

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

the answer is   c.) 1575 j.

explanation: