States of matter：練習題

What is the name for the process where a liquid changes into a solid?

Which statement correctly describes the movement of particles in a gas according to the kinetic theory?

An unknown solid S is added to \( 25\text{ g} \) of water at \( 20^\circ\text{C} \) until no more will dissolve. The mass of the remaining undissolved solid is subtracted from the initial mass to find that \( 8.5\text{ g} \) dissolved. If the temperature is raised to \( 60^\circ\text{C} \), the solubility becomes \( 62\text{ g/100 g water} \). What is the additional mass of S that can be dissolved in this specific sample?

A student adds a small amount of solid copper(II) sulfate to a beaker of distilled water and stirs until it completely disappears, forming a blue liquid. In this process, the copper(II) sulfate is known as the:

If \( 15\text{ g} \) of a salt dissolves in \( 50\text{ g} \) of water to form a saturated solution at \( 25^\circ\text{C} \), what is the solubility of the salt in \( \text{g per 100 g of solvent} \)?

Describe the changes in the arrangement and movement of particles when a liquid freezes to form a solid.

A student observes that the boiling point of a sample of water is 102 °C. Explain, with reference to the purity of the sample, why this value differs from the standard boiling point of water.

A glass tube is set up with cotton wool soaked in concentrated ammonia (\(NH_3\)) at one end and concentrated hydrochloric acid (\(HCl\)) at the other. Explain, using the kinetic theory of matter, why the white smoke of ammonium chloride forms closer to the hydrochloric acid end.

The table describes the arrangement and movement of particles in the three states of matter.

a) Identify the state of matter described as: "Particles are closely packed together in a regular arrangement and vibrate about fixed positions."

b) What is the name of the process when a substance changes from the state described in part (a) to a state where the particles are still close together but move randomly?

c) Describe the change in the energy of the particles as the substance undergoes the change of state mentioned in part (b).

Diffusion can be demonstrated using gas jars of air and bromine gas. A gas jar containing brown bromine gas is placed at the bottom, and a gas jar containing air is placed on top of it, separated by a glass plate.

a) Explain what happens when the glass plate is removed, and why the brown color eventually spreads throughout both jars.

b) Compare the rate of diffusion in gases with the rate of diffusion in liquids, giving a reason for the difference in terms of the kinetic theory of matter.