Amajor component of gasoline is octane c8h18 . when octane is burned in air, it chemically reacts with oxygen gas o2 to produce carbon dioxide co2 and water h2o . what mass of oxygen gas is consumed by the reaction of 6.0g of octane?

The mass of oxygen gas consumed by the reaction of 6.0 g of octane is  21 .0 g

That is;

For hydrocarbons with carbon and hydrogen

CxHy + O2(g) → CO2(g) + H2O(g)  

For Example;

Combustion of octane;

2C8H18(g) + 25O2(g) → 16CO2(g) + 18H2O(l)

Therefore; Two moles of octane combines with 25 moles of oxygen gas to yield 16 moles of carbon dioxide and 18 moles of water.

Therefore, we can calculate the mass of oxygen consumed by the reaction of 6.0 g of octane.

Number of moles = mass/ molar mass

Molar mass of octane = 114.23 g/mol

Number of moles of octane in 6.0 g

            = 6.0 g/114.23 g/mol

            = 0.0525 moles

From the balanced equation;

Two moles of octane combines with 25 moles of oxygen gas to yield 16 moles of carbon dioxide and 18 moles of water.

Therefore; moles of oxygen gas = (0.0525/2)× 25

                                                     = 0.65625 moles of Oxygen gas

Mass = number of moles × molar mass

Molar mass of oxygen gas = 32.0 g/mol

Mass of oxygen = 0.65625 moles × 32.0 g/mole

                          = 21 g of oxygen gas

Keywords: Combustion, hydrocarbons  

Level: High school

Subject: Chemistry  

Topic: Organic chemistry  

Sub-topic: Combustion of hydrocarbons

answer; 4 electrons;