(b) What is the relationship between viscosity and temperature?

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Viscosity is a measure of a fluid's resistance to flow. It describes how 'thick' or 'sticky' a fluid is.

As temperature increases, the kinetic energy of the molecules in a fluid also increases.

With higher kinetic energy, the molecules move more rapidly and can overcome intermolecular forces more easily.

This increased molecular movement at higher temperatures generally leads to a decrease in viscosity for liquids.

Therefore, the relationship between viscosity and temperature is typically inverse for liquids: as temperature increases, viscosity decreases.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Viscosity

Viscosity is a measure of a fluid's resistance to flow. It quantifies how thick or sticky a fluid is, with higher viscosity indicating a greater resistance to flow. For example, honey has a higher viscosity than water, meaning it flows more slowly. Viscosity is influenced by intermolecular forces and the temperature of the fluid.

Temperature's Effect on Viscosity

Temperature significantly affects the viscosity of liquids and gases. Generally, as temperature increases, the viscosity of liquids decreases because the increased kinetic energy allows molecules to move more freely, reducing resistance to flow. Conversely, for gases, viscosity tends to increase with temperature due to increased molecular collisions.

Intermolecular Forces

Intermolecular forces are the attractive forces between molecules that influence their physical properties, including viscosity. Stronger intermolecular forces result in higher viscosity, as molecules are held together more tightly, making it harder for them to move past one another. Understanding these forces helps explain why different substances exhibit varying viscosities at different temperatures.

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