Properties of Buffers · 缓冲溶液的性质
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| weak acid/wiːk ˈæsɪd/ | 弱酸 | ruò suān |
Choosing the right protector
- Not every buffer holds every pH.
- Each is tuned to a particular target near its acid's strength.
- The ratio of its two ingredients fine-tunes it.
- Pick the pair and the ratio, and you set the pH.
选择合适的保护者
- 并非每种缓冲溶液都能守住每一个 pH。
- 每一种都被调到它酸的强度附近的某个特定目标。
- 它两种成分的比例对它进行微调。
- 选好这一对和比例,你就设定了 pH。
Set by pKa and ratio
- A buffer's pH sits near the weak acid 弱酸's $\text{p}K_a$.
- The exact pH depends on the ratio of base to acid.
- Equal amounts give $\text{pH} = \text{p}K_a$.
由 pKa 和比例决定
- 缓冲溶液的 pH 位于弱酸的 $\text{p}K_a$ 附近。
- 确切的 pH 取决于碱与酸的比例。
- 等量给出 $\text{pH} = \text{p}K_a$。
A buffer with equal amounts of acid and conjugate base has a pH equal to... · 含有等量酸和共轭碱的缓冲溶液，其pH等于……
Equal amounts give $\text{pH} = \text{p}K_a$. · 等量给出$\text{pH} = \text{p}K_a$。
Changing the base-to-acid ratio shifts a buffer's pH. · 改变碱与酸的比例会改变缓冲溶液的pH。
The ratio fine-tunes the pH around $\text{p}K_a$. · 该比例微调$\text{p}K_a$周围的pH。
Strongest when balanced
- A buffer works best when acid and base are about equal.
- Then it resists added acid and added base equally well.
- That is near $\text{pH} = \text{p}K_a$.
平衡时最强
- 缓冲溶液在酸和碱大致相等时效果最好。
- 那时它同样好地抵抗加入的酸和加入的碱。
- 那接近 $\text{pH} = \text{p}K_a$。
A buffer resists pH change best when the acid and conjugate base are about equal. · 当酸和共轭碱大致相等时，缓冲溶液抵抗pH变化的效果最佳。
A 1:1 ratio handles added acid and base equally well. · 1:1的比例同样能很好地处理加入的酸和碱。
Picking the pair
- To buffer at a target pH, choose an acid with $\text{p}K_a$ near it.
- Then adjust the ratio to fine-tune.
- The closer $\text{p}K_a$ is to the target, the better it works.
挑选这一对
- 要在目标 pH 缓冲,选一个 $\text{p}K_a$ 靠近它的酸。
- 然后调整比例来微调。
- $\text{p}K_a$ 越靠近目标,它效果越好。
To make a buffer at pH 9, choose a weak acid with a $\text{p}K_a$... · 要制备pH为9的缓冲溶液，应选择具有……$\text{p}K_a$的弱酸。
Match the $\text{p}K_a$ to the target pH. · 将$\text{p}K_a$匹配到目标pH。
For the best buffer, match the acid's $\text{p}K_a$ to the target . · 为了获得最佳缓冲效果，应将酸的$\text{p}K_a$匹配到目标。
The $\text{p}K_a$ should be close to the desired pH. · $\text{p}K_a$应接近所需的pH。
You need a buffer at pH 5. Which weak acid should you pick?
- One with a $\text{p}K_a$ close to 5.
- Then set roughly equal amounts of the acid and its conjugate base.
你需要一个 pH 5 的缓冲溶液。你该选哪种弱酸?
- 一个 $\text{p}K_a$ 接近 5 的。
- 然后配大致等量的酸和它的共轭碱。
How a buffer resists · 缓冲溶液如何抵抗
In a CH3COOH / CH3COO- buffer, sort each addition by which component neutralises it. · 在CH3COOH / CH3COO-缓冲体系中，根据各组分中和哪种添加物，对每种添加物进行排序。
A buffer is effective roughly within how much of its $\text{p}K_a$? · 缓冲溶液在其$\text{p}K_a$的多少范围内有效？
Buffering fades more than about one unit from $\text{p}K_a$. · 当偏离$\text{p}K_a$超过一个单位时，缓冲能力减弱。
A buffer works best near its $\text{p}K_a$ (within about $\pm1$ pH unit) -- far from $\text{p}K_a$ it barely buffers. Changing the ratio shifts the pH, but only over a limited range. And to buffer at a target pH, match the acid's $\text{p}K_a$ to that pH, not to 7.
缓冲溶液在它的 $\text{p}K_a$ 附近(大约 $\pm1$ 个 pH 单位内)效果最好——远离 $\text{p}K_a$ 它几乎不缓冲。改变比例会移动 pH,但只在有限范围内。而且要在目标 pH 缓冲,就让酸的 $\text{p}K_a$ 与那个 pH 匹配,而不是与 7 匹配。
A buffer's pH sits near the weak acid's $\text{p}K_a$, tuned by the base-to-acid ratio (equal amounts give $\text{pH} = \text{p}K_a$). It buffers best when the two are balanced, so choose an acid whose $\text{p}K_a$ is close to your target pH.
缓冲溶液的 pH 位于弱酸的 $\text{p}K_a$ 附近,由碱酸比调节(等量给出 $\text{pH} = \text{p}K_a$)。它在两者平衡时缓冲最好,所以选一个 $\text{p}K_a$ 接近目标 pH 的酸。