12 g of salt in 3 l of water = 12 g of salt in 6 l of water = 30 g of sugar in 5 l of water =

Concentrations:

1. 12 g salt in 3 L water = 0,4 g salt / 100 ml water

2. 12 g salt in 6 L water)  = 0,2 g salt / 100 ml water

3. 30 g sugar in 5 L water) = 0,6 g sudar / 100 ml water

Explanation:

The given data are expressions to deal with the concentration of solutions (a kind of homogeneous mixtures).

There are many forms or units to express the concentrations of the mixtures.

The three cases show mass of solute (salt or sugar) in volume of solvent (water).

One form to express the concentration of the solutions is as mass of solute per 100 mililiters of solvent, which is useful to compare  with solutibility tables.

You can do that using the formula:

To find the concentrations of the given solutions, first you need to convert the volume of the solvent to mililiters (ml):

Concentrations:

1. (12 g salt / 3,000 ml water) × 100 = 0,4 g salt / 100 ml water

2. (12 g salt / 6,000 ml water) × 100 = 0,2 g salt / 100 ml water

3. (30 g sugar / 5,000 ml water) × 100 = 0,6 g sugar / 100 ml water