Answer to Question #63876 in General Chemistry for Ana Rodriguez

Question

how is the density of an oil spill measured and what steps would be taken to measure it

Answer 1

When oil leaks or spills into water it floats on the surface of both freshwater and saltwater. Oil floats because it is less dense than water. Density is a property of every liquid, solid, and gas. Density tells how much mass is in a specific volume (mass divided by the volume) of a material.
Formula density:
rho = m/V
The oil has a density of 0.85 g/cm3 and seawater has a density of 1.02 g/cm3. When these two liquids mixed, the denser seawater forms a layer underneath the less dense oil.
Factors that may affect the density of oil:
1. Evaporation. A small amount of weathering would easily change the density.
2. Temperature change. The density of oil does not change at the same rate as does the density of water.
3. Uptake of solid matter, sand and similar granular material particularly, will increase an oil's density. should be noted that some of the light material in oil would have actually decreased the density of the oil until such material became wetted.
4. Photooxidation and extreme weathering – certain oils are susceptible to photooxidation which creates a dense crust on the surface of exposed oil. The resulting material is often more dense than water.
Determination of density:
1. One of the methods for determining the density of spilled oil using the formulas above density.
Determine the mass of the collected oil and its volume. Then determine the density of the oil.
2. The radiometric measurement of density. The radiation, emitted from a shielded source is directed through the container with oil towards a scintillation detector at the opposite side. When irradiating container with oil the the radiation is attenuated. It is attenuated is directly proportional to the density of the measured material, since type of radiation and measuring geometry are constant. Moreover the measurement performance is not affected by temperature, pressure, viscosity, color or chemical properties of the measured material.