Question

1.5g of ethane on complete combustion gave 4.4g of carbon dioxide and 2.7g of water. show that the results are in accordance to the law of conservation of mass

Answer 1

Answer: This shows that the equation follow law of conservation of mass.

Explanation:

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another. Total mass on the reactant side is always equal to the total mass on the product side.

Combustion reaction is defined as the reaction in which a hydrocarbon burns in air to produce carbon dioxide and water molecule.

Chemical equation for the combustion of ethane follows:

$2C_2H_6+7O_2\rightarrow 4CO_2+6H_2O$

We are given:

On reactant side:

Mass of ethane = 1.5 g

Mass of oxygen = x g

On product side:

Mass of carbon dioxide = 4.4 g

Mass of water = 2.7 g

Total mass on product side = Total mass on reactant side

$4.4+2.7=1.5+x\\x=5.6$

Mass of oxygen will be 5.6 grams.

Thus, this equation follows Law of conservation of mass.

Answer 2

Answer:

Hydrocarbon undergoes combustion to form carbondioxide and water.

molecular mass of carbondioxide = 44gm

molecular mass of water  = 18 gm

mass of Carbon in 4.4 gm of carbondioxide = (12/44) * 4.4 = 1.2 gm

mass of Hydrogen in 2.7 gm of water = (2/18)*2.7 = 0.3 gm

So,

Total mass of Hydrogen and Carbon = (1.2 +.3)gm = 1.5 gm

This is the same mass before combustion.

Explanation:

So , the results are accordance with the law of conservation of mass.