# 1st Year Chem Notes 2018.pdf

## (1) What is atomic mass unit (a.m.u)? Give its value in grams. (2008) (2009) The unit used to express the relative atomic mass is called atomic mass unit. It is 1/12th of the mass of one carbon atom. 1 amu = 1.661× 10-27 kg or 1 amu = 1.661× 10-24 g (2) Law of conversation of mass has to be considered during stoichiometric calculations. (2008) Stoichiometric calculations are based on balanced chemical equation. During this it is assumed that matter is neither created nor destroyed but changes from one form to another. So Law of conversation of mass has to be considered during stoichiometric calculations otherwise with unbalanced chemical equations stoichiometric calculations will not be possible. (1) What is atomic mass unit (a.m.u)? Give its value in grams. (2008) (2009)

The unit used to express the relative atomic mass is called atomic mass unit. It is 1/12th of the mass

of one carbon atom. 1 amu = 1.661× 10-27 kg or 1 amu = 1.661× 10-24 g

(2) Law of conversation of mass has to be considered during stoichiometric calculations. (2008)

Stoichiometric calculations are based on balanced chemical equation. During this it is assumed that

matter is neither created nor destroyed but changes from one form to another. So Law of

conversation of mass has to be considered during stoichiometric calculations otherwise with

unbalanced chemical equations stoichiometric calculations will not be possible.

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