Solute is a substance that dissolves in a solvent in order to form a solution. Solutes can be in liquid, gaseous or solid phase. Normally, in a solution, solutes are in a lesser amount than the solvents. When a solution has the maximum amount of solutes it can dissolve, then the solution is said to be saturated.
The atomic mass of methane (CH4)is 12 amu for the carbon plus 4 x 1 amu for the four hydrogens, for a total of 16 amu. Therefore, the molar mass of methane is 16g.