Assume that identical hydrometers are placed in ethanol (sp gr 0.7893) and in chloroform (sp gr 1.4832). In which liquid will the hydrometer float higher? Explain.

Verified step by step guidance

1. Understand the concept of specific gravity (sp gr): Specific gravity is the ratio of the density of a substance to the density of water (at 4°C, which is approximately 1 g/mL). A higher specific gravity indicates a denser liquid.
2. Recall the principle of buoyancy: An object floats when the upward buoyant force exerted by the liquid equals the downward gravitational force on the object. The buoyant force depends on the density of the liquid and the volume of liquid displaced by the object.
3. Compare the specific gravities of ethanol (0.7893) and chloroform (1.4832): Chloroform has a higher specific gravity, meaning it is denser than ethanol.
4. Relate density to the floating height of the hydrometer: In a denser liquid (higher specific gravity), the hydrometer will displace less liquid to balance its weight, causing it to float higher. Conversely, in a less dense liquid (lower specific gravity), the hydrometer will sink deeper to displace more liquid to balance its weight.
5. Conclude: Since chloroform has a higher specific gravity than ethanol, the hydrometer will float higher in chloroform than in ethanol.

Key Concepts

Specific Gravity

Specific gravity (sp gr) is a dimensionless quantity that compares the density of a substance to the density of water at a specified temperature. It indicates whether a substance will float or sink in water. A specific gravity less than 1 means the substance is less dense than water and will float, while a specific gravity greater than 1 indicates it is denser and will sink.

Buoyancy

Buoyancy is the upward force exerted by a fluid that opposes the weight of an object immersed in it. According to Archimedes' principle, an object will float if the buoyant force is equal to or greater than its weight. The degree to which an object floats in a fluid depends on the fluid's density relative to the object's density.

Hydrometer Functionality

A hydrometer is an instrument used to measure the specific gravity of liquids. It floats in the liquid, and the level to which it sinks indicates the liquid's density. In less dense liquids, the hydrometer will float higher, while in denser liquids, it will sink lower, allowing for the comparison of different liquids based on their specific gravities.