Density Measurement

Question 1

In which case would a hydrometer float higher, in oil or in water? Explain your answer.

Answer 1

The more submersed a hydrometer is the more dense the fluid that it is measuring. Since water is denser than oil the hydrometer would float higher in water.

Question 2

When using a hydrometer, is the temperature of the fluid of any concern?

Answer 2

Yes as temperature directly affects density. As temperature rises the density of a substance decreases due to thermal expansion.

Question 3

When using relative density, why should the temperature be stated and what would you
use (assume) if no temperature was stated?

Answer 3

Since relative density is a ratio to a reference standard at a certain temperature the temperature of the standard needs to be stated. If temperature is not given 15 Celsius is assumed

Question 4

Why is density measured?

Answer 4

1) Calculate mass flow of a fluid for custody transfer
2) Brewing operations
3) To find out a concentration of a substance
4) Determine batch detection

Question 5

What factors affect density?

Answer 5

1) Substance composition
2) Temperature
3) Pressure

Question 6

Describe how a hydrometer works

Answer 6

The float displaces a fixed volume of fluid and the resulting buoyant force becomes a function of fluid density. The degree scale of submersion is an indication of fluid density.