6. Chemical Quantities & Aqueous Reactions

An aqueous solution of which of the following would conduct electricity?

Which of the following statements is false?

Aqueous solutions of three different substances, AX, AY, and AZ, are represented by the three accompanying diagrams. Identify each substance as a strong electrolyte, a weak electrolyte, or a nonelectrolyte. (a)

(b)

(c)

Use the molecular representations shown here to classify each compound as a nonelectrolyte, a weak electrolyte, or a strong electrolyte (see Figure 4.6 for the element color scheme). (a)

Refer to the figure to answer questions 4 and 5. The images are a molecular representation of three different substances, AX3, AY3, and AZ3, dissolved in water. (Water molecules are omitted for clarity.)

Which of the substances is the weakest electrolyte? (LO 4.6) (a) AX3 (b) AY3 (c) AZ3 (d) All of the substances are strong electrolytes.

Which of the following substances will produce a solution that does not conduct electricity when it dissolves in water? (LO 4.6) (a) NaOH (b) HNO3 (c) Na2SO4 (d) CH3OH

Magnesium, the element, is produced commercially by electrolysis from a molten salt (the 'electrolyte') using a cell similar to the one shown here. (b) Chlorine gas is evolved as voltage is applied in the cell. Knowing this, identify the electrolyte.

State whether each of the following statements is true or false. Justify your answer in each case. (a) Electrolyte solutions conduct electricity because electrons are moving through the solution.

State whether each of the following statements is true or false. Justify your answer in each case. (b) If you add a nonelectrolyte to an aqueous solution that already contains an electrolyte, the electrical conductivity will not change.

We have learned in this chapter that many ionic solids dissolve in water as strong electrolytes; that is, as separated ions in solution. Which statement is most correct about this process? (a) Water is a strong acid and therefore is good at dissolving ionic solids. (b) Water is good at solvating ions because the hydrogen and oxygen atoms in water molecules bear partial charges. (c) The hydrogen and oxygen bonds of water are easily broken by ionic solids.

When carbon dioxide dissolves in water, it is in equilibrium with carbonic acid H2CO3, which is a weak electrolyte. Write the chemical equation for the ionization of H2CO3.

When carbon dioxide dissolves in water, it is in equilibrium with carbonic acid H2CO3, which is a weak electrolyte. What solutes are present in an aqueous solution of this compound?

Acetone, CH3COCH3, is a nonelectrolyte; hypochlorous acid, HClO, is a weak electrolyte; and ammonium chloride, NH4Cl, is a strong electrolyte. (a) What are the solutes present in aqueous solutions of each compound? What solute particles are present in an aqueous solution of HClO?

Acetone, CH3COCH3, is a nonelectrolyte; hypochlorous acid, HClO, is a weak electrolyte; and ammonium chloride, NH4Cl, is a strong electrolyte. (b) If 0.1 mol of each compound is dissolved in solution, which one contains 0.2 mol of solute particles, which contains 0.1 mol of solute particles, and which contains somewhere between 0.1 and 0.2 mol of solute particles?

Acetone, CH3COCH3, is a nonelectrolyte; hypochlorous acid, HClO, is a weak electrolyte; and ammonium chloride, NH4Cl, is a strong electrolyte. (a) What are the solutes present in aqueous solutions of each compound? What solute particles are present in an aqueous solution of CH3COCH3?

State whether each of the following statements is true or false. Justify your answer in each case. (b) HF is a strong acid.

An aqueous solution of an unknown solute is tested with litmus paper and found to be acidic. The solution is weakly conducting compared with a solution of NaCl of the same concentration. Which of the following substances could the unknown be: KOH, NH3, HNO3, KClO2, H3PO3, CH3COCH3 (acetone)?

Classify each of the following substances as a nonelectrolyte, weak electrolyte, or strong electrolyte in water: (a) HF

The following pictures represent aqueous solutions of three acids HA (A = X, Y, or Z), with surrounding water mol-ecules omitted for clarity. Which of the three is the strongest acid, and which is the weakest?

Assume that the electrical conductivity of a solution depends on the total concentration of dissolved ions and that you measure the conductivity of three different solutions while carrying out titration procedures: (a) Begin with 1.00 L of 0.100 M KCl, and titrate by adding 0.100 M AgNO3. (b) Begin with 1.00 L of 0.100 M HF, and titrate by adding 0.100 M KOH. (c) Begin with 1.00 L of 0.100 M BaCl2, and titrate by add-ing 0.100 M Na2SO4. Which of the following graphs corresponds to which titration? (1)

(2)

(3)

The following aqueous solutions were tested with a light bulb conductivity apparatus, as shown in Figure 4.3. What result—dark, dim, or bright—do you expect from each? (a) 0.10 M potassium chloride (b) 0.10 M methanol (c) 0.10 M acetic acid

The following aqueous solutions were tested with a light bulb conductivity apparatus, as shown in Figure 4.3. What result—dark, dim, or bright—do you expect from each? (a) 0.10 M hydrofluoric acid (b) 0.10 M sodium chloride (c) 0.10 M glucose (C6H12O6)

Individual solutions of Ba(OH)2 and H2SO4 both conduct electricity, but the conductivity disappears when equal molar amounts of the solutions are mixed. Explain.

A solution of HCl in water conducts electricity, but a solu-tion of HCl in chloroform, CHCl3, does not. What does this observation tell you about how HCl exists in water and how it exists in chloroform?

Classify each of the following substances as a strong electrolyte, weak electrolyte, or nonelectrolyte. (a) HBr (b) HF (c) NaClO4 (d) (NH4)2CO3 (e) NH3 (f) Ethyl alcohol

Is it possible for a molecular substance to be a strong electrolyte? Explain.

For each compound (all water soluble), would you expect the resulting aqueous solution to conduct electrical current? a. CsCl b. CH3OH c. Ca(NO2)2 d. C6H12O6

Classify each compound as a strong electrolyte or nonelectrolyte. a. MgBr2 b. C12H22O11 c. Na2CO3 d. KOH

Why do we use a double arrow to show the dissociation of a weak acid or weak base in aqueous solution?

Each of the following compounds is soluble in water. for which compounds do you expect the resulting aqueous solution to conduct electrical current?

Classify each of the following as a strong electrolyte or nonelectrolyte.

Of the species below, only ________ is not an electrolyte.

Classify each of the following substances as a nonelectrolyte, weak electrolyte, or strong electrolyte in water.

Which of the following is an electrolyte

Which of the following is true of electrolytes

A substance is classified as an electrolyte because

Which substance is an electrolyte?

A substance that carries an electric current when dissolved in water is called a(n)