Question: "What is the specific gravity of gasoline given that its density is 0.7 g/mL."
I don't really understand what specific gravity is, or what equation I need to use to solve the problem. Please help.
I don't really understand what specific gravity is, or what equation I need to use to solve the problem. Please help.
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Almost always (in chemistry) the term "specific" means that the number is in relation to a standard. It is a ratio of the variables value to a standard's value.
With specific gravity, the ratio is density of the substance to the density of water.
The problem with this is that we know (and so should you!) that density changes with temperature.
Usually the density of water used is at 4°C, the densest water is at 1 atm.
I have seen specific gravity reported at 4°/4°, 17°/4°, 20°/4°, 25°/4°, 20°/20°, 25°/25° and several others. This nomenclature means density of water at the denominator temperature and the density of the sample measured at the numerator temperature. So 20°/4° means sample was measured at 20°C and the water at 4°C.
Your question has no information about the temperature so assume specific gravity is the same as density (of course units cancel,)(but are usually are reported anyway).
With specific gravity, the ratio is density of the substance to the density of water.
The problem with this is that we know (and so should you!) that density changes with temperature.
Usually the density of water used is at 4°C, the densest water is at 1 atm.
I have seen specific gravity reported at 4°/4°, 17°/4°, 20°/4°, 25°/4°, 20°/20°, 25°/25° and several others. This nomenclature means density of water at the denominator temperature and the density of the sample measured at the numerator temperature. So 20°/4° means sample was measured at 20°C and the water at 4°C.
Your question has no information about the temperature so assume specific gravity is the same as density (of course units cancel,)(but are usually are reported anyway).
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Relative density, or specific gravity,[1][2] is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity usually means relative density with respect to water. The term "relative density" is often preferred in modern scientific usage.
If a substance's relative density is less than one then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water then a substance with a relative density (or specific gravity) less than 1 will float in water. For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink.
If a substance's relative density is less than one then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water then a substance with a relative density (or specific gravity) less than 1 will float in water. For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink.
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I only know the specific gravity when the given is a temperature.