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?

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?

Potassium superoxide, KO2, is often used in oxygen masks (such as those used by firefighters) because KO2 reacts with CO2 to release molecular oxygen. Experiments indicate that 2 mol of KO21s2 react with each mole of CO21g2. (b) Indicate the oxidation number for each atom involved in the reaction in part (a). What elements are being oxidized and reduced?

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 NH4Cl?

Which of the following schematic drawings best describes a solution of Li2SO4 in water (water molecules not shown for simplicity)?

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)

The concept of chemical equilibrium is very important. Which one of the following statements is the most correct way to think about equilibrium? (a) If a system is at equilibrium, nothing is happening. (b) If a system is at equilibrium, the rate of the forward reaction is equal to the rate of the back reaction. (c) If a system is at equilibrium, the product concentration is changing over time.

You are presented with a white solid and told that due to careless labeling it is not clear if the substance is barium chloride, lead chloride, or zinc chloride. When you transfer the solid to a beaker and add water, the solid dissolves to give a clear solution. Next an Na2SO41aq2 solution is added and a white precipitate forms. What is the identity of the unknown white solid?

Which of the following ions will always be a spectator ion in a precipitation reaction? (a) Cl- (b) NO3- (c) NH4+ (d) S2- (e) SO42-

An aqueous solution contains 1.2 mM of total ions. (a) If the solution is NaCl(aq), what is the concentration of chloride ion?

An aqueous solution contains 1.2 mM of total ions. (b) If the solution is FeCl3(aq), what is the concentration of chloride ion?

Which data set, of the two graphed here, would you expect to observe from a titration like that shown in Figure 4.18?

You are titrating an acidic solution with a basic one, and just realized you forgot to add the indicator that tells you when the equivalence point is reached. In this titration, the indicator turns blue at the equivalence point from an initially colorless solution. You quickly grab a bottle of indicator and add some to your titration beaker, and the whole solution turns dark blue. What do you do now?

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.

(a) Do colloids made only of gases exist? Why or why not?

(b) In the 1850s, Michael Faraday prepared ruby-red

colloids of gold nanoparticles in water that are still stable

today. These brightly colored colloids look like solutions.

What experiment(s) could you do to determine whether a

given colored preparation is a solution or colloid?

Choose the best answer: A colloidal dispersion of one liquid

in another is called (a) a gel, (b) an emulsion, (c) a foam,

(d) an aerosol

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.

Would you expect that an anion would be physically closer to the oxygen or to the hydrogens of water molecules that surround it in solution?

Ignoring protolysis reactions (i.e. proton transfer reaction), specify what ions are present in a solution upon dissolving each of the following substances in water: (a)Li₂CO₃

Ignoring protolysis reactions (i.e. proton transfer reaction), specify what ions are present in a solution upon dissolving each of the following substances in water: (c) Na₂Cr₂O₇

Specify what ions are present upon dissolving each of the following substances in water: (a) MgI₂

Specify what ions are present upon dissolving each of the following substances in water: (b) K₂CO₃

Specify what ions are present upon dissolving each of the following substances in water: (c) HClO₄

Specify what ions are present upon dissolving each of the following substances in water: (d) NaCH₃COO

Formic acid, HCOOH, is a weak electrolyte. What solutes are present in an aqueous solution of this compound?

Formic acid, HCOOH, is a weak electrolyte. Write the chemical equation for the ionization of HCOOH.