density
Mass.
The volume and mass of a substance are independent of the substance itself, but depend upon how much there is of the substance The density of a substance is the relation between how much volume you have of a substance and how much mass that volume has (and vice-versa). It is independent of how much there is of the substance and is thus a characteristic of the substance.
No, but they are related. Density = mass / volume. Mass is often informally called the "amount of substance".It can be measured by its gravitational effects (mass in kilograms or pounds, actually any 'weight'),or by its inertia (the resistance of any physical object to a change in its state of motion or rest. It is represented numerically by an object's mass).Better statement would be:Density is a measure of how much mass is in a certain volume of a particular substance.
They would use density to measure the volume of a substance :)
ml is a measure of volume; mg is a measure of mass. The mass of each ml depends on the density of the substance you are dealing with.
A litre is a measure of volume not mass. What substance you have a litre of would determine its mass.
If the density of the substance is known, then you can calculate it. Density = Mass/Volume, so Mass = Density x Volume
It depends on the density of the substance being measured. There is no direct conversion. Milligrams are a measure of mass, cubic centimetres are a measure of volume.
Apples and oranges! One is a measure of volume and one is a measure of mass (weight). If you want to know how much volume a certain mass of some substance has, you have to start out by knowing the density of that substance.
Weigh it to determine the mass, then determine how much volume it displaces (in something it does not dissolve in). Divide mass by volume, you've got density.
humidity.
It means how much a standard volume of a substance weighs - or more precisely, how much mass it has. If a liter of one substance has more mass than a liter of another substance, the first substance is said to have greater density. Density is defined as mass divided by volume.