True or False: (If false give the correct statement) 

The molar mass of ${\mathrm{CO}}_2$ is $42$ grams.
 

Write the different types of isotopes of oxygen and its percentage abundance. 
 

Define: Atomicity.

Give any two examples for heterodiatomic molecules. 

What is Molar volume of a gas? 

Calculate the number of water molecules present in one drop of water which weighs $0.18\mathrm{g}$. 

${\mathrm{N}}_2+3{\mathrm{H}}_2\to 2{\mathrm{NH}}_3$

(The atomic mass of nitrogen is $14$, and that of hydrogen is $1$) 

$1$ mole of nitrogen (_____ $\mathrm{g}$) + $3$ moles of hydrogen (_____ $\mathrm{g}$)$\to$ $2$ moles of ammonia (_____ $\mathrm{g}$)