The saying "oil and water do not mix" is particularly relevant to the petroleum industry. the most desirable "light crude" has an average density of about 0.82g/mL and thus floats on water. However, some of the more dense "heavy crude" will sink in the water. How dense must crude oil be to sink in water?

Explained

Explanation:

Density of water is 1 g/mL. for any liquid to float on water it's density should be less than water and for sinking in water its density should be more than water. Any other liquid with density less than 1 g/mL will float on the water surface, that is why light crude which has density of 0.82 g/mL floats on water for crude oil to sink, it's density must be greater than 1 g/mL.