Properties of Solids I

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Questions and Answers

What defines the phase transformation from solid to liquid?

Sublimation

Vaporization

Condensation

Melting (correct)

Which intermolecular force is typically the weakest among solids, liquids, and gases?

Van der Waals forces (correct)

Ionic bonds

Covalent bonds

Hydrogen bonds

What characteristic of powders is crucial in determining their pharmaceutical application?

Electrical conductivity

Thermal expansion

Melting point

Particle size (correct)

Which of the following statements about true and bulk density is correct?

True density is the mass of the powder divided by its volume, excluding porosity. Signup and view all the answers

What does the contact angle measure in relation to wettability of a solid?

The tendency of a liquid to spread out on a solid surface Signup and view all the answers

What is the primary difference between true volume and bulk volume?

True volume accounts for porosity, whereas bulk volume does not. Signup and view all the answers

How is porosity determined?

Through the calculation of the void ratio times 100. Signup and view all the answers

What does a lower angle of repose indicate about a powder's flow properties?

The powder flows more freely. Signup and view all the answers

What does bulkiness measure in terms of powder characteristics?

The volume occupied by a selected weight of the powder. Signup and view all the answers

How is the apparent density of a powder calculated?

Mass divided by bulk volume. Signup and view all the answers

Which of the following correctly describes the void of a powder?

The difference between bulk volume and true volume divided by bulk volume. Signup and view all the answers

What does the contact angle indicate about the wettability of a powder?

Smaller angles indicate better wettability. Signup and view all the answers

What is the relationship described by Young's Equation regarding wettability?

The interfacial tension affects the contact angle of liquids on solids. Signup and view all the answers

What property is primarily affected by changes in temperature in solids, liquids, and gases?

Kinetic energy Signup and view all the answers

Which solid state form is recognized for its unique molecular packing?

Crystalline Signup and view all the answers

What is the primary reason for using pharmaceutical salts in drug formulation?

Bioavailability Signup and view all the answers

What is the role of particle size analysis in pharmaceuticals?

Affecting dose uniformity Signup and view all the answers

Which method is NOT used to measure particle size in pharmaceuticals?

Titration Signup and view all the answers

What effect does an increase in pressure have on the volume of a gas, according to Boyle's Gas Law?

Volume decreases Signup and view all the answers

What is a characteristic of amorphous solids compared to crystalline solids?

No long-range order Signup and view all the answers

In the context of solid state forms, what can hygroscopicity lead to?

Decreased shelf life Signup and view all the answers

Which factor is important for the stability of pharmaceutical solids?

Chemical and physical stability Signup and view all the answers

What primarily determines the ability of a powder to flow in pharmaceutical applications?

Particle size and distribution Signup and view all the answers

Why are cocrystals developed in pharmaceuticals?

To improve solubility and stability Signup and view all the answers

What is meant by the term 'angle of repose' in micromeritics?

The angle at which particles begin to flow Signup and view all the answers

What type of solid includes molecules that form a regularly ordered structure?

Crystalline solids Signup and view all the answers

Which of the following is a common characteristic of pharmaceutical aerosols?

Use gas as a propellant Signup and view all the answers

Study Notes

States of Matter

Solids, liquids, and gases are the three states of matter.
The different states of matter are due to differences in intermolecular forces.
Substances that exist as solids at room temperature have stronger intermolecular forces compared to liquids and gases.
Energy can be transferred into kinetic (thermal) energy which increases temperature.
Gases are compressible, liquids are not, and solids are not.
Temperature increases the kinetic energy of molecules, increasing the movement of particles, thus causing phase transformations.
Pressure can also cause phase transformations in a closed system, with increased pressure favoring the liquid and solid states.

Pharmaceutical Gases

Pharmaceutical gases include Nitrous oxide, nitric oxide, oxygen, and carbon dioxide.
Aerosols often use liquefied gases as a dispersion medium or propellant.

Solids

Solids can be crystalline or amorphous.
Crystalline solids have a repeating molecular arrangement, like polymorphs.
Amorphous solids lack a long-range repeating order.
Pharmaceutical salts are formed from acidic or basic drugs with a counterion to form a crystalline salt.
Cocrystals are crystalline molecular complexes formed from two or more neutral molecules.
When designing pharmaceuticals, it is important to consider the solid form as it affects solubility, dissolution rate, bioavailability, hygroscopicity, manufacturing properties, and stability.

Solid Stability

Temperature influences solid stability, causing transformations like dehydration and melting.
The melting point of solids relates to the magnitude of intermolecular forces.
The heat of fusion is the energy required to transform a solid into a liquid.

Powders

Powder is a physical form of a substance composed of finely divided particles.
Powders can be classified as very coarse, coarse, moderately coarse, fine, and very fine based on their particle size.
The particle size, size distribution, and shape of powders are important micromeritic properties influencing mixing, blending, dose uniformity, powder flow, aerosolization, dissolution, and suspendability characteristics.

Particle Size Analysis

Sieving is one method for particle-size analysis.
Optical microscopy, scanning electron microscopy, and transmission electron microscopy are common techniques to determine particle size.

Micromeritic Properties

Micromeritics studies the properties of powders involving: particle size, shape, angle of repose, true density, bulk density, porosity, voids, true volume, bulk volume, and bulkiness.
True volume is the space occupied by particles themselves and is determined by true density.
Bulk volume is the total volume of the powder including the spaces between particles.
Void is the ratio of space over the bulk volume.
Porosity is a percentage calculated from the void.
Bulkiness is the reciprocal of apparent density.
The angle of repose describes how easily a powder flows.

Wettability of Powders

Wettability is the ability of a liquid to spread across a solid surface.
The contact angle is a measure of wettability.
Young's equation describes the relationship between surface tensions and contact angle.
Wettability affects the dispersion of powders in liquids, the penetration of liquids into tablets, and the hardness of tablets.

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Description

Explore the fundamental concepts of states of matter, including solids, liquids, and gases, and their molecular behavior. This quiz also covers the role of pharmaceutical gases and their applications in various fields. Test your understanding of intermolecular forces, phase transformations, and the unique properties of different states.