Write equations for the half-reactions that occur at the anode and cathode in the electrolysis of molten $\mathrm{KBr}$. What are the products formed at the anode and cathode in the electrolysis of aqueous KBr?

A voltaic cell is constructed using the reaction of chromium metal and iron(II) ions.
$2 \mathrm{Cr}(\mathrm{s})+3 \mathrm{Fe}^{2+}(\mathrm{aq}) \rightarrow 2 \mathrm{Cr}^{3+}(\mathrm{aq})+3 \mathrm{Fe}(\mathrm{s})$
Complete the following sentences: Electrons in the external circuit flow from the electrode to the electrode. Negative ions move in the salt bridge from the half-cell to the half-cell. The half-reaction at the anode is, and that at the cathode is

Calculate the mass of $\mathrm{Mg}$ that could be obtained by the process described in Question 6 from $1.0 \mathrm{~L}$ of seawater. To prepare 100. $\mathrm{kg}$ of $\mathrm{Mg}$, what volume of seawater would be needed? (The density of seawater is $1.025 \mathrm{~g} / \mathrm{cm}^3$.)

Balance the following redox equations. All occur in basic solution.\

$$\mathrm{N}_2 \mathrm{H}_4(\mathrm{aq})+\mathrm{Ag}_2 \mathrm{O}(\mathrm{s}) \rightarrow \mathrm{N}_2(\mathrm{~g})+\mathrm{Ag}(\mathrm{s})$$

Balance the following redox equations. All occur in basic solution.\

$$\mathrm{Fe}(\mathrm{OH})_2(\mathrm{~s})+\mathrm{CrO}_4^{2-}(\mathrm{aq}) \rightarrow$$

$$\mathrm{Fe}(\mathrm{OH})_{\mathrm{s}}(\mathrm{s})+\left[\mathrm{Cr}(\mathrm{OH})_4\right]^{-}(\mathrm{aq})$$