pH and pOH of Strong Acids and Bases · 强酸和强碱的pH与pOH
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| pH/piː eɪtʃ/ | pH值 | pH zhí |
A tidy scale for acidity
- Concentrations of $\text{H}^+$ span many powers of ten.
- A logarithm squeezes that huge range into one neat number.
- Low numbers mean sour and reactive; high numbers mean slippery.
- One scale runs from battery acid to bleach.
一个整洁的酸度标度
- $\text{H}^+$ 的浓度跨越许多个十的幂。
- 对数把那个巨大的范围压缩成一个整洁的数。
- 数字低表示酸而活泼;数字高表示滑腻。
- 一个标度从电池酸一直到漂白水。
The pH scale
- pH pH值 measures acidity: $\text{pH} = -\log[\text{H}^+]$.
- A lower pH is more acidic; a higher pH is more basic.
- Each unit is a factor of ten in $[\text{H}^+]$.
pH 标度
- 酸碱度衡量酸度:$\text{pH} = -\log[\text{H}^+]$。
- pH 越低越酸;越高越碱。
- 每一个单位是 $[\text{H}^+]$ 的十倍。
A lower pH means the solution is... · 较低的pH意味着溶液...
Lower pH means higher $[\text{H}^+]$ -- more acidic. · 较低pH意味着较高$[\text{H}^+]$——更酸性。
Going from pH 5 to pH 3 changes $[\text{H}^+]$ by a factor of... · 从pH 5到pH 3，$[\text{H}^+]$变化了...倍。
Two pH units is $10^2 = 100$ times. · 两个pH单位是$10^2 = 100$倍。
pH is the ____ logarithm of $[\text{H}^+]$. · pH是$[\text{H}^+]$的____对数。
$\text{pH} = -\log[\text{H}^+]$.
pOH and the sum
- pOH measures the hydroxide side: $\text{pOH} = -\log[\text{OH}^-]$.
- At 25 degrees, $\text{pH} + \text{pOH} = 14$.
- Know one and you know the other.
pOH 与它们的和
- pOH 衡量氢氧根一侧:$\text{pOH} = -\log[\text{OH}^-]$。
- 在 25 度时,$\text{pH} + \text{pOH} = 14$。
- 知道一个就知道另一个。
A solution has $\text{pH} = 9$ at 25 degrees. Its pOH? · 某溶液在25度时有$\text{pH} = 9$。其pOH？
$\text{pOH} = 14 - \text{pH} = 14 - 9 = 5$.
Strong means fully ionized
- A strong acid ionizes completely, so $[\text{H}^+]$ equals its concentration.
- A strong base gives $[\text{OH}^-]$ equal to its concentration.
- Then just take the negative log.
强意味着完全电离
- 强酸完全电离,所以 $[\text{H}^+]$ 等于它的浓度。
- 强碱给出等于它浓度的 $[\text{OH}^-]$。
- 然后只需取负对数。
The pH scale · pH标度
For a strong acid or base, the pH follows straight from the concentration; pH + pOH = 14. · 对于强酸或强碱，pH直接来自浓度；pH + pOH = 14。
For a strong acid, $[\text{H}^+]$ equals the acid's concentration. · 对于强酸，$[\text{H}^+]$等于酸的浓度。
Strong acids ionize completely, so this shortcut holds. · 强酸完全电离，因此此捷径成立。
Find the pH of $0.001\ \text{M}$ strong acid.
- $[\text{H}^+] = 0.001 = 10^{-3}$, since it is fully ionized.
- $\text{pH} = -\log(10^{-3}) = 3$.
求 $0.001\ \text{M}$ 强酸的 pH。
- $[\text{H}^+] = 0.001 = 10^{-3}$,因为它完全电离。
- $\text{pH} = -\log(10^{-3}) = 3$。
Find the pH of a $0.01\ \text{M}$ strong acid. · 求$0.01\ \text{M}$强酸的pH。
$[\text{H}^+] = 10^{-2}$, so $\text{pH} = -\log(10^{-2}) = 2$. · $[\text{H}^+] = 10^{-2}$，所以 $\text{pH} = -\log(10^{-2}) = 2$。
pH uses a negative log, so a smaller $[\text{H}^+]$ gives a bigger pH. The "$[\text{H}^+]$ equals concentration" shortcut works only for strong acids and bases (fully ionized), not weak ones. And each pH unit is a 10-fold change, not a small one.
pH 用负对数,所以更小的 $[\text{H}^+]$ 给出更大的 pH。"$[\text{H}^+]$ 等于浓度"的捷径只对强酸和强碱(完全电离)有效,弱的不行。而且每一个 pH 单位是 10 倍的变化,不是小变化。
pH $= -\log[\text{H}^+]$ measures acidity, with pOH $= -\log[\text{OH}^-]$ and $\text{pH} + \text{pOH} = 14$. For a strong acid or base, $[\text{H}^+]$ or $[\text{OH}^-]$ equals the concentration, so you just take the negative log. Each unit is a factor of ten.
酸碱度 $= -\log[\text{H}^+]$ 衡量酸度,pOH $= -\log[\text{OH}^-]$,且 $\text{pH} + \text{pOH} = 14$。对强酸或强碱,$[\text{H}^+]$ 或 $[\text{OH}^-]$ 等于浓度,所以只需取负对数。每一个单位是十倍。