## Chemistry: Atoms First (2nd Edition)

a. $[H_3O^+] = 6.7 \times 10^{- 15}M$: Basic. b. $[H_3O^+] = 2.8\ M$: Acidic c. $[H_3O^+] = 1.0 \times 10^{- 7}M$: Neutral d. $[H_3O^+] = 1.4 \times 10^{- 11}M$: Basic
$[H_3O^+]$ represents the same thing as $[H^+]$. - If $[H_3O^+] = [OH^-]$: Neutral - If $[H_3O^+] > [OH^-]$: Acidic - If $[H_3O^+] < [OH^-]$: Basic. a. $[OH^-] * [H_3O^+] = Kw = 10^{-14}$ $1.5 * [H_3O^+] = 10^{-14}$ $[H_3O^+] = \frac{10^{-14}}{ 1.5 \times 10^{- 0}}$ $[H_3O^+] = 6.667 \times 10^{- 15}M$ b. $[OH^-] * [H_3O^+] = Kw = 10^{-14}$ $3.6 \times 10^{- 15} * [H_3O^+] = 10^{-14}$ $[H_3O^+] = \frac{10^{-14}}{ 3.6 \times 10^{- 15}}$ $[H_3O^+] = 2.778M$ c. $[OH^-] * [H_3O^+] = Kw = 10^{-14}$ $1.0 \times 10^{- 7} * [H_3O^+] = 10^{-14}$ $[H_3O^+] = \frac{10^{-14}}{ 1 \times 10^{- 7}}$ $[H_3O^+] = 1 \times 10^{- 7}$ d. $[OH^-] * [H_3O^+] = Kw = 10^{-14}$ $7.3 \times 10^{- 4} * [H_3O^+] = 10^{-14}$ $[H_3O^+] = \frac{10^{-14}}{ 7.3 \times 10^{- 4}}$ $[H_3O^+] = 1.37 \times 10^{- 11}M$