Chemistry 104 Module 6 Exam: Solids & Colligative Properties, Exams of Chemistry

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Chemistry104 Module 6 Examination practices with best solutions 2025

Amorphous solids - answers particles are arranged in a random fashion Colligative properties - answers physical properties of solvents that are dependent on the concentration of the solute present and the identity of the solvent but not on the identity of the solute. They include vapor pressure, freezing point and boiling point Colloids - answers heterogeneous mixtures which appear to homogeneous one-phase mixtures but are actually composed of particles too small to be seen with the naked eye Condensation - answers process of gas being converted to liquid Critical point - answers the temperature above which a substance cannot exist in the liquid phase Critical pressure - answers the lowest pressure required for the substance to exist as a liquid at the critical point Crystalline solids - answers particles are arranged in one of several different orderly, repeating, geometric patterns Electrolytes - answers ionic or very polar compounds which dissolve to form solutions of ions which conduct an electric current Fluids - answers substances like liquids and gases which have no fixed shape and so they flow Ionization - answers the splitting of molecules to form ions Molality - answers the number of moles of solute present per kilogram of solvent Molarity - answers the number of moles of solute present per liter of solution Nonelectrolytes - answers compounds which dissolve to form solutions of molecules which do not conduct an electric current Phase - answers any state of matter such as solid, liquid or gas Strong electrolytes - answers solutes that ionize completely Sublimation - answers the conversion of a solid directly to the gas state

Surface tension - answers the force that causes a liquid which is in contact with a gas like air to assume a shape that has the least amount of surface area causing the surface to act like a thin elastic sheet Triple point - answers the temperature and pressure at which the solid, liquid and gas phases can coexist Vapor pressure - answers pressure exerted by vapor molecules above a liquid Weak electrolytes - answers solutes that only partially ionize Why are liquids the least common state of matter? - answers they can exist only within a relatively narrow range of temperatures and pressures Differentiate between evaporation and vaporization - answers Vaporization is the conversion of liquid particles to vapor at the boiling point temperature of the material. The process of liquid converting to vapor molecules can also take place in a very limited manner at temperatures lower than the boiling point and is called evaporation Differentiate between a crystal lattice and a unit cell - answers A crystal lattice is the orderly, repeating geometric pattern in which the particles of a crystalline solid are arranged. The unit cell is the smallest section of the crystal lattice having that arrangement of particles Why does a phase change occur at one temperature rather than over a temperature range? - answers During a phase change, the temperature of the material remains constant as all of the energy being added is being used to overcome forces of attraction between the particles and separate them so the temperature does not rise. Over any other portions of the temperature range, when a material is heated, the temperature of the material will rise as the energy added causes the molecules to move faster and demonstrate a higher temperature, which is really a measure of the kinetic energy of the molecules Why does diffusion take place quickly in a gas, more slowly in a liquid and not at all in a solid? - answers Diffusion is the non- energy-requiring movement of particles from regions of higher concentration to regions of lower concentration. Diffusion in a liquid occurs more slowly than in a gas since the gas particles are moving more rapidly. Solids do not show the property of diffusion since the particles in a solid can only vibrate around a fixed point rather than move throughout the sample. Explain water's concave meniscus in terms of cohesive and adhesive forces - answers Cohesive forces are the attractions between particles of the same type, such as the bonds between water molecules whereas adhesive forces are attractions between a particle of one type and particles of a different type, such as the bonds between water molecule and those of its glass container. These cohesive and adhesive forces combine to cause liquids to form a meniscus (curved surface) in a glass tube. A liquid with strong cohesive forces, such as water, tries to roll itself into a ball to minimize surface tension, but water is also attracted to the walls of any tube by adhesive forces, causing the water to form a concave meniscus. Explain the difference in the properties of graphite and diamond which are both pure carbon - answers In graphite the atoms are arranged in planes which can slide relative to one another making graphite a good solid lubricant. In diamond the atoms are arranged in tetrahedrons which are tightly bonded together making carbon the hardest substance known. Explain why the vapor pressure of a liquid increases with increasing temperature - answers Water molecules in the liquid state freely vibrate and rotate. As the temperature rises, the vibrations and rotations become intense enough to overcome the forces that keep