The heaviest atom amongst the following is

Consider the following data:

Element	Atomic mass
$A$	$12.01$
$B$	$35.5$

$A$ and $B$ combine to form a new substance $X$. If $4 \ mol$ of $B$ combine with $1 \ mol$ of $A$ to give $1 \ mol$ of $X$,then the weight of one mole of $X$ is ........... $g$.

Given that the abundances of isotopes $^{54}Fe$,$^{56}Fe$ and $^{57}Fe$ are $5 \%$,$90 \%$ and $5 \%$,respectively,the atomic mass of $Fe$ is

What do you mean by molar weight?

$1.520 \ g$ of the hydroxide of a metal on ignition gave $0.995 \ g$ of oxide. The equivalent weight of the metal is:

In the chemical scale,the relative atomic mass of the naturally occurring isotopic mixture of oxygen atoms $({}^{16}O, {}^{17}O, {}^{18}O)$ is taken as: