Write the molecular formula for
Nitric oxide

This question refers to the elements of the periodic table with atomic numbers $3$ to $18$. Some of the elements are shown by letters but the letters are not the usual symbols of the elements.

 If $\mathrm{A}$ combines with $\mathrm{F}$, what would be the formula of the resulting compound?

Write the chemical formula for the following element;

Nitrogen.

Ammonia burns in oxygen and the combustion, in the presence of a catalyst, may be represented by

$2{\mathrm{NH}}_3+\frac{5}{2}{\mathrm{O}}_2\to 2\mathrm{NO}+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{H}=1,\mathrm{N}=14,\mathrm{O}=16\right)$

What mass of steam is produced when $1.5\mathrm{g}$ of nitrogen monoxide is formed?

Complete the missing link: The ratio by mass of $\mathrm{S}$ and $\mathrm{O}$ in ${\mathrm{SO}}_2$ is _____.

A : $\left(1:2\right)$

B : $\left(1:1\right)$

C : $\left(3:1\right)$

Enter your correct answer as A, B or C.

Write the chemical formula of the following:

The empirical formula of a compound is ${\mathrm{C}}_2{\mathrm{H}}_5$. It has a vapour density of $29$. Determine the relative molecular mass of the compound and hence its molecular formula.

Write the chemical formula for the following element.

Hydrogen.

Solid ammonium dichromate (relative molecular mass $252$) decomposes as under:

${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\to {\mathrm{N}}_2+{\mathrm{Cr}}_2{\mathrm{O}}_3+4{\mathrm{H}}_2\mathrm{O}$

If $63 \mathrm{g}$ of ammonium dichromate decomposes, what will be the loss of the mass?

What is mean by:

Molecular mass

The compound $\mathrm{A}$ has $26.7\% \mathrm{C},71.1\%$ $\mathrm{O}$ and $2.2\%\mathrm{H}$. If the relative molecular mass of $\mathrm{A}$ is $90$, what is the molecular formula of $\mathrm{A}$?

(Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$)