How to find volume of substance from molar concentration

The concentration of a substance dissolved in water $i$ is known in (mol/m3), so is the molar mass in (g/mol) and the density in (g/m3). 


I want to find the volume of this substance in m3.


I have two possible ideas for equations to use:
$$\mathrm{volume}\_i= \frac{\mathrm{mass}\_i}{c\_i \times M\_{W,i}},$$
however, to use this equation I need to know the mass of the substance, which is not obvious.


Also I could use something like this:
$$\mathrm{volume}\_i = \frac{c\_i \times M\_{W,i} \times \mathrm{volume}\_{?}}{\rho\_i },$$
however, I'm not sure what volume$\_?$ would be, as I don't know the volume of the solution and I am trying to find the volume of the substance $i$. 


Any ideas how to find the mass in the first equation or the volume in the second equation, or other equations to use?


*Extra comments:*
My real aim is to find the volume of the solution so I can use the following formula for volume concentration, where I already know the volume concentration $\phi\_i $:
$$\phi\_i = \frac{\mathrm{volume}\_i} {\mathrm{volume}\_\mathrm{solution}} $$
 or 
$$\mathrm{volume}\_\mathrm{solution} = \frac{\mathrm{volume}\_i} {\phi\_i} $$




Nothing has been said about the actual volume of the solution, only concentration of the solution has been given.


Assume that $c$ moles of solute is present in 1m$^3$ of solution.


Then mass of solute=c\*molar mass 


volume of solute \* density of solute = c\* molar mass


From this equation, volume of solute can be known.


*Clearly, if the volume of the solution increases, the volume of the solute will also increase. Since the volume of the solution has not been given, it must give you a hint to take the above assumption.* 


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