What will be the mass of one atom of ${}^{12}C$?

When an ion absorbs $6 \times 10^{20}$ electrons,it gets reduced. What is the number of gram equivalents of the ion?

If $m_1 \ g$ of metal $A$ displaces $m_2 \ g$ of another metal $B$ from its salt solution,and their equivalent weights are $E_1$ and $E_2$ respectively,how is the equivalent weight of $A$ expressed?

If the mass of an electron is halved,the mass of a proton is doubled,and the mass of a neutron is $3/4$ of its original mass,then what will be the new atomic mass of an $O^{16}$ atom?

In chlorine gas,the ratio of $Cl^{35}$ and $Cl^{37}$ is

When a metal oxide is heated in a stream of hydrogen,reduction occurs. After reduction,$3.15 \, g$ of the oxide yields $1.05 \, g$ of the metal. What can we conclude about the metal?