161. Naphthalene (moth balls) contains 93·71% carbon and 6·29% hydrogen. If its molar mass is 128 g mol^–1, calculate its molecular formula.

A welding fuel gas contains carbon and hydrogen only. Burning a small space of it in oxygen gives 3.38 g carbon dioxide, 0·690g of water and no other products. A volume of 10·0L (measured at STP) of this welding gas is found to weigh 11·6g. Calculate: (i) empirical formula (ii) molar mass of the gas and (iii) molecular formula.

Butyric acid contains only C, H and O, 4.24mg sample of butyric acid is completely burnt. It gives 8.45mg of carbon dioxide and 3.46mg of water. What is the mass percentage of each element in butyric acid?

If the elemental composition of butyric acid is found to be 54.2%C, 9.2%H and 36.6%O, determine the empirical formula.

The molecular mass of butryic acid was determined by experiment to be 88 amu. what is the molecular formula?

What are the implications of a chemical equation?
Or
What informations are conveyed by a chemical equation?

What are the limitations or drawbacks of a chemical equation?

How can we make a chemical equation more informative?
Or
How can we remove the drawbacks or limitations of a chemical equation?

Write balanced chemical equation for the following reactions making them as informative as you can:

(i) Reaction between magnesium carbonate and dilute sulphuric acid to form an aqueous solution of magnesium sulphate, carbondioxide gas and water.

(ii) Reaction between methane gas (CH₄) and oxygen gas to produce carbondioxide, water vapours and heat.