What is a apparent loss of mass?

Answer 1

You must have seen that when substances like wood, wax, coal, oil, etc. are burnt, they seem to disappear, or leave a very small quantity of residue. It looks as if the mass is much lesser. Well, the loss of some mass of these substances is only apparent. As per the Law of conservation of masses, matter is neither created nor destroyed but can be transformed from one form to other. The products formed after burning are mostly gaseous e.g., carbon dioxide and water vapour, which escape into the air. As we do not measure the amount of the gases liberated, an apparent loss of mass is noticed.

However, if we can trap the gaseous products and find their masses, we will realise that the combined mass of the products is always greater than the original mass.

This can be easily proved by the following experiment.

Take a wide mouthed glass cylinder, open at both ends. Insert a wire gauze and place it a little away from the bottom. Now place a layer of anhydrous calcium chloride (CaCl2) on it and cover this layer again by cotton wool. On top of it, form a layer of soda lime. Again put a third layer of cotton wool. (Fig.5.11).

Cut out a circular disc, using soft wood, so as to fit tight at the bottom end of the glass cylinder. Two holes are made to let in air. Before fixing the wooden disc to the bottom of the cylinder, fix a candle as shown in the above figure. Find the mass of the whole arrangement (say 'a' g).

Then take out the wooden disc, light the candle and fix it back immediately. Let the three-fourths of the candle burn. Now if you block the air holes with your fingers, the candle gets put off. Cool the arrangement for some time. Find the mass of the apparatus [say 'b' g].

You will observe that 'b' g > 'a' g, showing that the product of combustion of a candle has greater mass than the candle itself. This is because when a candle burns, carbon dioxide and water vapour are the gaseous products formed. The absorption process using anhydrous calcium chloride and soda lime measures these gases. Hence, there appears to be an apparent gain in mass

Answer 2

An apparent loss of mass refers to a situation where an object or system appears to have lost mass without any actual mass being lost. This can occur due to factors like measurement errors, changes in the environment (such as temperature or pressure), or incomplete understanding of the system being studied. It is important to carefully investigate the cause of apparent mass loss to ensure accurate measurements and conclusions.

Answer 3

Apparent loss of mass could be the result of a physical change if something turns into a clear, colorless gas and dissipates into the air.

Answer 4

Mass is a physical property, so the loss of mass can result from a physical change.

Answer 5

is a chemical change

Answer 6

yes

Answer 7

Evaporation