Chemistry Questions

Question

Seawater contains 8.0*10^-1 cg of the element strontium per kilogram of seawater. Assuming that all the strontium could be recovered, how many grams of strontium could be obtained from one cubic meter of sea water? Assume the density of water is 1g/mL.

Answer 1

Calculate the mass of the 1 m³ of seawater by converting the volume to mass using the density of water. Next use the concentration of Sr given in cg/1 kg seawater to calculate the amount of Sr in your 1 m³ seawater.

Convert 1 m³ to the unit of cm³ by dimensional analysis, (1 m)³ = (100 cm)³ or 1 000 000 cm³

and 1 cm³ = 1 mL, therefore 1 m³ = 1 000 000 mL. For water, 1 g = 1 mL (density),

so 1 m3 seawater = 1 000 000 mL = 1 000 000 g seawater (convert to kg) or 1 000 kg seawater.

Mass of seawater (kg) x ^{amount of Sr (cg)}/ _{1 kg seawater} = amount of Sr (cg) in 1 m³ seawater