MASS AND WEIGHT- DIFFERENCES

Difference between Mass and Weight

Mass	Weight
The mass of a body is the matter contained in it .	The weight of a body is the product of its mass and acceleration due to gravity.
The mass of a body is always a constant quantity and does not change anywhere.	The weight of a body is a variable quantity and depends on the value of acceleration due to gravity.
Mass is a scalar quantity.	Weight is a vector quantity.
The mass of a body remains same at all places.	The weight of a body is zero at the centre of the earth.

Some general questions that a student may know for his/her knowledge

1.If the mass of a body on the earth is 10 kg then on moon the mass is 10 kg
The reason behind this is that mass remains same at all places .
Again the weight of the body changes at different on the earth with the variable value of acceleration due to gravity. It will be mg where m is the mass and g is acceleration due to gravity whose value on the earth is calculated approximately 9.8 m/sec², therefore weight =mg=10 x 9.8=98 N and its weight on the moon will be mg =10 x1.6=16 N because the value of g for the moon is 1.6 m/sec².

2. Is there any change in the weight of a body when it is taken from Kolkata
to Darjeeling explain this statement - The value of ‘g’ changes from place to place on the surface .The value of ‘g’ decreases with the rise of altitude(height). Since Darjeeling is situated at a higher altitude then Kolkata, hence the value of ‘g’ is less than Darjeeling with respect to Kolkata. Thus the body will experience less weight at Darjeeling  then Kolkata.

Every thing in the universe obeys some laws regarding nature so mass is also a part of the universe it also obeys the same law.

Law of conservation of mass : The law of conservation of mass deals with the relation between the mass of reactants and the products during the chemical change. It was postulated by A. Lavoisier.

The law of conservation of mass states that during any physical or chemical change , the total mass of the product is equal to the total mass of the reactants
                                                                    Or
matter is neither created nor destroyed during any physical or chemical change.

Verification of law of conservation of mass

Landoll’s experiment : In this experiment, take two solutions of sodium chloride and silver nitrate separately in the two limbs of H shaped tube (Landoll’s tube). Seal the tube and weight it. After weighing shake the tubes thoroughly to mix the solutions. The reaction occurs between the solution of silver nitrate and sodium chloride. A white precipitate of silver chloride is formed as ‘
    AgNO₃ + NaCl = AgCl +NaNO₃
After the reaction weight the tube again. We will observe that the weight remains practically unchanged. This   verify the law of conservation of mass.