# Find the volume of sea water

The concentration of all salts present in sea-water is 3.52 % (m/v). Calculate the volume of sea-water, which on evaporation will produce 5 kg of salt.

My attempt: \begin{align} 5~\mathrm{kg} &= 5000~\mathrm{g}\\ \text{Volume} &= \frac{\text{Mass}}{\text{Density}}\\ \text{Volume of salt} &= 5000~\mathrm{mL}\\ \text{Total Volume of Solution} &= \text{Volume of Salt} + \text{Volume of water}\\ \therefore \text{Total Volume of Solution} &= 5000 + x\\ \text{Concentration} &= \left(\frac{\text{Mass of Solute}}{\text{Volume of Solution}}\right) \cdot 100\\ 3.52 &= \left(\frac{5000}{5000 + x}\right) \cdot 100\\ x &= 137045.45 \end{align}

• Percent proportions are dimensionless. 3.52% means that there are 0.0352 kg salt in 1.000 kg sea water. To calculate the volume you need to know the density of 3.52% sea water which is 1.025 kg/l at 25°C. – aventurin Jun 30 '16 at 19:04
• @aventurin Please note the incorrect, but common usage of the percent concentration, as stated in Wikipedia. – Martin - マーチン Jul 4 '16 at 4:02
• I have updated your post with chemistry markup. If you want to know more, please have a look here and here. We prefer to not use MathJax in the title field, see here for details. What is actually your question? Do you want to know if your approach is correct? – Martin - マーチン Jul 4 '16 at 4:10