If the mass table of atomic weights were established with oxygen atom assigned a value of $100,$ the atomic weight of carbon would be

Suppose two elements $X$ and $Y$ combine to form two compounds $XY_{2}$ and $X_{2}Y_{3}$. If $0.05 \ mol$ of $XY_{2}$ weighs $5 \ g$ while $3.011 \times 10^{23}$ molecules of $X_{2}Y_{3}$ weighs $85 \ g$,then atomic masses of $X$ and $Y$ are respectively :

What is meant by $1 \ amu$ or $1 \ u$?

An element,$X$ has the following isotopic composition:
$^{200}X: 90\%$,$^{199}X: 8.0\%$,$^{202}X: 2.0\%$
The weighted average atomic mass of the naturally occurring element $X$ is closest to......$amu$.

In chlorine,the isotopes $^{35}Cl$ and $^{37}Cl$ are present in the ratio $3:1$. Calculate the atomic mass of chlorine. (in $amu$)

If the molecular mass and atomic mass of sulphur are $256$ and $32$ respectively,its atomicity is: