Question

a)Write a note on convent or molecular hydrides. Give examples
b) What is water-gas shift reaction?
c)Write any three postulated of Dalton's atomic theory.
d)What is empirical formula? Give an example of a compound whose empirical formula and molecular formula are same
e)What is intensive property of a system? Pickout the intensive property from mass. internal energy density and volume.
f) Describe the experiment to determine the internal energy change by bomb calorimeter with neat labelled diagram.

Answer 1

(a) These are hydrides that form when hydrogen reacts with $P-$block elements. These are highly electronegative elements, for more than hydrogen. Hydrogen atoms form a covalent bond with these $P-$block atoms. The general chemical formula for covalent hydrides is ${XH}_{(8-n)}$, where $n$ is the number of electrons the element has in its outer most shell.

Ex :- $HCl$, $HF$.

(b) The water gas shift reaction describes the reaction of carbon monoxide and water vapour to form carbon dioxide and hydrogen.

$CO+H_{2}O\rightleftharpoons {CO}_2+H_2$

(c) i) All matter consists of indivisible particle called atoms.

ii) Atoms can not be created or destroyed.

iii) Atoms of same element can combine in more than one ratio to form two or more compounds.

(d) A Chemical formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.

One molecule of ethylene, molecular formula is $C_2{H}_4$ and its empirical formula is ${CH}_2$.