What is the specific gravity of mercury, the liquid used in thermometers, if it has a density of 13.6 g/mL
The Correct Answer and Explanation is:
The specific gravity of a substance is defined as the ratio of its density to the density of water. Since the density of water is typically 1 g/mL at 4°C, the specific gravity of a substance is numerically equal to its density in g/mL.
Given that the density of mercury is 13.6 g/mL, we can calculate the specific gravity as follows:
Specific Gravity = Density of Mercury / Density of Water
Substituting the values:
Specific Gravity = 13.6 g/mL / 1 g/mL = 13.6
So, the specific gravity of mercury is 13.6.
Explanation:
- Density refers to the mass per unit volume of a substance. It is typically expressed in g/mL or kg/m³. In the case of mercury, the given density is 13.6 g/mL, which means that each milliliter of mercury weighs 13.6 grams.
- Specific Gravity is a dimensionless quantity because it is the ratio of the substance’s density to the density of water. Water is often used as a reference because its density is conveniently set to 1 g/mL at 4°C (the temperature at which water reaches its maximum density).
- The specific gravity of mercury tells us that it is 13.6 times denser than water. This is why mercury is often used in thermometers, as its high density makes it ideal for measuring temperature changes. A small change in temperature will cause a noticeable change in the mercury’s volume, making it easily readable on a scale.
In practical terms, the high specific gravity of mercury allows it to remain in a liquid state over a wide range of temperatures, especially in the colder environments where thermometers are often used.
