U-world: Gen-Chem: Solution Chemistry #3

galvanic cell

-device in which chemical energy from a spontaneous redox reaction is changed to electrical energy that can be used to do work -This reaction occurs spontaneously, and Eocell is a positive value.

common ion effect

the lowering of the solubility of an ionic compound as a result of the addition of a common ion

If researchers wanted to replicate physiological conditions by increasing the SBF temperature to 37°C, how would this change affect the solubility product constant and equilibrium pH of Mg(OH)2 dissolution?

Ksp and equilibrium pH will both increase. **For endothermic reactions, heat can be treated as one of the reactants because it is required for the reaction. Heat can also be treated as a product for exothermic reactions

Would the concentration of H2SO4 remain constant as a lead storage battery is discharged?

No, because water is one of the products produced when the battery is discharged

ANOX REDCAT

-Although electron flow is in the opposite direction when a battery is charging as when it is discharging, electrons always flow from the anode to the cathode. -Reduction occurs at the cathode, and oxidation occurs at the anode

Which statement correctly describes the Pb electrode when the lead storage battery is charging as shown in Figure 1?

It is the cathode and PbSO4 is reduced at its surface **When a battery is charging, it is an electrolytic cell, and when it is discharging, it is a galvanic cell. The difference between charging and discharging is determined by which electrode is the cathode and which is the anode.

Throughout the experiment, researchers monitored the amount of magnesium that dissolved at various time points. Which of the following is NOT a valid test for the rate of magnesium corrosion?

Periodically measure the amount of OH− produced by titrating the beaker contents with HCl **When determining the corrosion rate of the magnesium disks, the experimental technique cannot affect the outcome (ie, the corrosion rate) or it will skew the results

Q=It

The charge is the product of the current I (amperes, or C/s) and time (t, seconds)

Magnesium hydroxide begins to precipitate onto the magnesium metal surface when which of the following expressions is true?

[Mg2+][OH−]^2 > 8.9 × 10^−12 **The solubility product constant Ksp describes the concentrations of slightly soluble compounds in solution at equilibrium

If the electromotive force of the battery in an AED is found to be −2.0 V while it is charging, the battery is functioning as a:

electrolytic cell **The electromotive force Eocell for a cell is the difference between the standard reduction potential of the reaction at the cathode and the anode. E∘cell=E∘cathode−E∘anode For an electrolytic cell, this value is negative, indicating that the oxidation-reduction reaction is not spontaneous. During the charging phase of a rechargeable battery, an external potential is applied to force the oxidation-reduction reaction to proceed in a nonspontaneous direction