How can the Law of Conservation of Mass apply to a burning log?

Answer 1

As the solid wax melts and cumbusts, the wax combines with oxygen and turns into a gas, carbon dioxide among other things. The mass of the wax and wick are converted into gases and the mass is conserved.

Answer 2

As a candle burns, the massdecreases as the liquid wax is the fuel source that is burnt to produce the flame. Many people would say that the candle's mass stays the same as the wax which is melted solidifies again at the base, and this would conserve the mass. However, it is important to bear in mind that the candle isn't just melting, it is also burning and so mass is lost through evaporation.

Answer 3

The law of conservation of mass states that the sum of the mass of the reagents must be equal to the sum of the mass of the products.

In another way we can say that before and after the reaction there must be the same number of atoms (moles) of each element.

In a burning candle you have the following reaction

CxHy + a*O2 --> b*CO2 + c*H2O

>Where "CxHy" means the tip of the candle that burns which is generally made of a polymer. >a,b and c are numbers you use to multiply each part so that in the end you have the same number of each element on either side of the equation.

So in the end, the number of atoms and the atoms themselves remain equal, they only changed positions. Since the mass of each atom doesn't change, then sum of the masses doesn't change too.

Answer 4

No matter can be lost at all! during reactions, never.

The weight of the solid material (candle wax) is decreasing, but the products formed increase in mass (carbondioxide and water). This increase (though not easily weighted on a balance) is even larger than the loss of solid, because also oxygen from air is used (=disappearing) for burning.

Answer 5

Organic mass in the candle wax gets burnt and the exhaust carbon evaporates.

learn physics 101 and think with your head before you want to question a physics law, did you actually think the candle burns on the wick along? Do gasoline not get used up when you burn them?

Answer 6

It applies to all systems. The chemical equation for burning wood is balanced the number of atoms involved in the burning is the same as the number of atoms contained in the products of the burning. While the wood seems to disappear, one needs to understand that its components are being turned into gases.

Answer 7

If a candle is burned in a large airtight container, the mass before, during and after are the same. For ordinary burning of a candle things are much more difficult. You need to take the mass of the candle and add the mass of the oxygen from the air that is used in combustion. However, you will not know how much oxygen is used since if you do not use a sealed container, fresh air will replace the oxygen-depleted air. Similarly the outputs of combustion are the molten wax, carbon dioxide, water vapour and any other gases produced as well as particulate materials that may be ejected in the flame. Some of the gases and vapours will disappear before you can obtain their mass.

Answer 8

The mass of the initial candle is identical with the sum of masses of released gases from burning and the residues remained.

Answer 9

The mass of the candle is equal to the sum of products: water, carbon dioxide, smoke, other solid of gaseous residues.