Ch.4 - Reactions in Aqueous Solution

Problem 59a

Chapter 4, Problem 59a

(a) Is the number of moles of ions present in a solution an intensive or an extensive property?

Verified step by step guidance

Understand the difference between intensive and extensive properties: Intensive properties do not depend on the amount of substance, while extensive properties do.

Consider the definition of moles of ions: The number of moles of ions in a solution is directly related to the quantity of the substance present.

Recognize that extensive properties include properties like mass, volume, and the number of moles, which change with the amount of substance.

Conclude that since the number of moles of ions depends on the amount of solution, it is an extensive property.

Remember that intensive properties, such as temperature and concentration, remain constant regardless of the amount of substance.

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Key Concepts

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

Intensive vs. Extensive Properties

Intensive properties are those that do not depend on the amount of substance present, such as temperature and density. In contrast, extensive properties depend on the quantity of material, like mass and volume. Understanding this distinction is crucial for analyzing properties of substances in chemistry.

Moles and Ions

A mole is a unit in chemistry that represents 6.022 x 10²³ entities, such as atoms or ions. When discussing solutions, the number of moles of ions indicates the concentration and behavior of the solution. This concept is fundamental in stoichiometry and solution chemistry.

Properties of Solutions

The properties of solutions can be classified as either intensive or extensive. For example, the concentration of ions in a solution is an intensive property, while the total number of moles of ions is extensive, as it changes with the volume of the solution. Recognizing these classifications helps in understanding solution behavior and reactions.

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Related Practice

Textbook Question

The metal cadmium tends to form Cd²⁺ ions. The following observations are made: (i) When a strip of zinc metal is placed in CdCl₂(aq), cadmium metal is deposited on the strip. (ii) When a strip of cadmium metal is placed in Ni(NO₃)(aq), nickel metal is deposited on the strip. (b) Which elements more closely define the position of cadmium in the activity series?

Textbook Question

The following reactions (note that the arrows are pointing only one direction) can be used to prepare an activity series for the halogens:

Br₂(aq) + 2 NaI(aq) → 2 NaBr(aq) + I₂(aq)

Cl₂(aq) + 2 NaBr(aq) → 2 NaCl(aq) + Br₂(aq)

(a) Which elemental halogen would you predict is the most stable, upon mixing with other halides?

Textbook Question

The following reactions (note that the arrows are pointing only one direction) can be used to prepare an activity series for the halogens:

Br₂(aq) + 2 NaI(aq) → 2 NaBr(aq) + I₂(aq)

Cl₂(aq) + 2 NaBr(aq) → 2 NaCl(aq) + Br₂(aq)

(b) Predict whether a reaction will occur when elemental chlorine and potassium iodide are mixed.

Textbook Question

(b) Can you identify which one between 0.10 mol ZnCl2 and 0.1M ZnCl2 contains more Zn2+ ion? Why?

Textbook Question

You make 1.000 L of an aqueous solution that contains 35.0 g of sucrose (C12H22O11). (b) How many liters of water would you have to add to this solution to reduce the molarity you calculated in part (a) by a factor of two?

Textbook Question

(a) Calculate the molarity of a solution that contains 0.175 mol ZnCl₂ in exactly 150 mL of solution.