Which is heavier.....?

Question

How heavy is:
a) 100 litres of drinking water?
b) 100 litres of sea water?

Answer 1

The "heavier" of the two will have a higher weight, and thus a larger mass (assuming they are both in the same gravitational field).
Weight = mass * gravity
A higher weight = higher mass if g is constant.

Since we are given a specific volume of water, the more massive of the two would also be the denser of the two liquids,
Density = mass / volume
A higher mass = higher density if v is constant

Salt water is denser than fresh water, therefore for a given volume (100 L), sea water will weight more than drinking water (assuming one does not drink sea water).

Density of sea water:
http://www.windows.ucar.edu/tour/link=/earth/Water/density.html&edu=high

Answer 2

Both graduatedted cylinders of water contain 100 ml. The sea water has the salt also, so it is heavier.The salt is between the water molecules, so it is denser.

Answer 3

sea water is heavier

Answer 4

sea water, it has more mineral / salt content