[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.01,Default,,0000,0000,0000,,我们知道如果把水留在容器里不管
Dialogue: 0,0:00:05.05,0:00:06.67,Default,,0000,0000,0000,,假设有些水
Dialogue: 0,0:00:06.71,0:00:07.90,Default,,0000,0000,0000,,那么它会到达
Dialogue: 0,0:00:07.95,0:00:10.73,Default,,0000,0000,0000,,自身解离的平衡
Dialogue: 0,0:00:10.77,0:00:14.29,Default,,0000,0000,0000,,所以一部分水会变成一些氢离子
Dialogue: 0,0:00:14.33,0:00:19.11,Default,,0000,0000,0000,,这些会粘上其它的水分子
Dialogue: 0,0:00:19.18,0:00:20.86,Default,,0000,0000,0000,,变成H3O+
Dialogue: 0,0:00:20.91,0:00:23.73,Default,,0000,0000,0000,,不过只要写成氢离子就行
Dialogue: 0,0:00:23.78,0:00:26.16,Default,,0000,0000,0000,,氢离子其实是个游离的质子
Dialogue: 0,0:00:26.20,0:00:29.43,Default,,0000,0000,0000,,加上氢氧根离子
Dialogue: 0,0:00:29.48,0:00:31.23,Default,,0000,0000,0000,,同时我们也知道
Dialogue: 0,0:00:31.27,0:00:36.93,Default,,0000,0000,0000,,在25°C的平衡状态下
Dialogue: 0,0:00:36.97,0:00:38.02,Default,,0000,0000,0000,,记住啦
Dialogue: 0,0:00:38.06,0:00:40.31,Default,,0000,0000,0000,,平衡常数和平衡反应
Dialogue: 0,0:00:40.35,0:00:42.38,Default,,0000,0000,0000,,只由温度确定
Dialogue: 0,0:00:42.42,0:00:43.49,Default,,0000,0000,0000,,没别的了
Dialogue: 0,0:00:43.53,0:00:46.90,Default,,0000,0000,0000,,假设一个分子 当然啦
Dialogue: 0,0:00:46.94,0:00:49.73,Default,,0000,0000,0000,,也是在25°C下
Dialogue: 0,0:00:49.77,0:00:51.76,Default,,0000,0000,0000,,我们上上集讲过这个
Dialogue: 0,0:00:51.80,0:00:53.04,Default,,0000,0000,0000,,平衡常数
Dialogue: 0,0:00:53.06,0:00:54.50,Default,,0000,0000,0000,,我们来复习一下
Dialogue: 0,0:00:54.55,0:00:58.26,Default,,0000,0000,0000,,就是产物的浓度
Dialogue: 0,0:00:58.30,0:01:03.60,Default,,0000,0000,0000,,除以反应物的浓度
Dialogue: 0,0:01:03.65,0:01:05.71,Default,,0000,0000,0000,,但在这里反应物只有水
Dialogue: 0,0:01:05.76,0:01:06.92,Default,,0000,0000,0000,,而它是溶剂
Dialogue: 0,0:01:06.97,0:01:10.05,Default,,0000,0000,0000,,如果反应物无处不在
Dialogue: 0,0:01:10.10,0:01:11.87,Default,,0000,0000,0000,,你回想一下那个直观的例子
Dialogue: 0,0:01:11.91,0:01:13.62,Default,,0000,0000,0000,,就知道它存在的概率是1
Dialogue: 0,0:01:13.67,0:01:16.07,Default,,0000,0000,0000,,它就是无处不在
Dialogue: 0,0:01:16.11,0:01:17.67,Default,,0000,0000,0000,,所以不用考虑它
Dialogue: 0,0:01:17.71,0:01:19.33,Default,,0000,0000,0000,,或者你可以看成除以1之类的
Dialogue: 0,0:01:19.35,0:01:23.90,Default,,0000,0000,0000,,这等于水的平衡常数
Dialogue: 0,0:01:23.94,0:01:27.15,Default,,0000,0000,0000,,我们已知这个常数是10的-14次方
Dialogue: 0,0:01:27.19,0:01:30.15,Default,,0000,0000,0000,,因为水单独存在时
Dialogue: 0,0:01:30.19,0:01:35.09,Default,,0000,0000,0000,,氢离子浓度是10的-7次方
Dialogue: 0,0:01:35.13,0:01:39.15,Default,,0000,0000,0000,,氢氧根的浓度也是10的-7次方
Dialogue: 0,0:01:39.20,0:01:41.41,Default,,0000,0000,0000,,同时对它们取对数
Dialogue: 0,0:01:41.43,0:01:46.16,Default,,0000,0000,0000,,如果你对Kw…
Dialogue: 0,0:01:46.20,0:01:47.63,Default,,0000,0000,0000,,这是什么意思呢？
Dialogue: 0,0:01:47.67,0:01:49.35,Default,,0000,0000,0000,,如果把p放在某个东西前面
Dialogue: 0,0:01:49.40,0:01:51.47,Default,,0000,0000,0000,,就表示 对这个东西取负常用对数
Dialogue: 0,0:01:51.51,0:01:54.02,Default,,0000,0000,0000,,取10^(-14)的负对数
Dialogue: 0,0:01:54.06,0:01:57.45,Default,,0000,0000,0000,,10^(-14)的对数就是-14
Dialogue: 0,0:01:57.50,0:01:59.95,Default,,0000,0000,0000,,所以它的负对数就是14
Dialogue: 0,0:02:00.00,0:02:06.62,Default,,0000,0000,0000,,结果pKw就是14 就等于…
Dialogue: 0,0:02:06.66,0:02:10.27,Default,,0000,0000,0000,,如果我把另一边也取负对数
Dialogue: 0,0:02:10.32,0:02:11.49,Default,,0000,0000,0000,,我来算算
Dialogue: 0,0:02:11.54,0:02:13.18,Default,,0000,0000,0000,,这就是对数的性质了
Dialogue: 0,0:02:13.22,0:02:16.51,Default,,0000,0000,0000,,这就属于数学而不是化学的范畴了
Dialogue: 0,0:02:16.55,0:02:22.18,Default,,0000,0000,0000,,所以是H+的对数乘以OH-
Dialogue: 0,0:02:22.22,0:02:24.10,Default,,0000,0000,0000,,乘以咱们的氢氧根
Dialogue: 0,0:02:24.15,0:02:26.15,Default,,0000,0000,0000,,这是等价的 只是对数运算
Dialogue: 0,0:02:26.20,0:02:32.34,Default,,0000,0000,0000,,这等于 氢的负对数减去
Dialogue: 0,0:02:32.39,0:02:40.34,Default,,0000,0000,0000,,或者你可以说是加上 OH-的负对数
Dialogue: 0,0:02:40.37,0:02:42.21,Default,,0000,0000,0000,,来看看这是啥？
Dialogue: 0,0:02:42.22,0:02:47.23,Default,,0000,0000,0000,,这就是pH嘛
Dialogue: 0,0:02:47.28,0:02:50.35,Default,,0000,0000,0000,,它就是一个负对数
Dialogue: 0,0:02:50.39,0:02:53.24,Default,,0000,0000,0000,,这是10的-7次方 对吧？
Dialogue: 0,0:02:54.48,0:02:56.11,Default,,0000,0000,0000,,它的常用对数是-7
Dialogue: 0,0:02:56.15,0:02:57.59,Default,,0000,0000,0000,,把负号提前
Dialogue: 0,0:02:57.63,0:03:00.08,Default,,0000,0000,0000,,pH就等于7了
Dialogue: 0,0:03:00.12,0:03:01.72,Default,,0000,0000,0000,,那这是啥呢？
Dialogue: 0,0:03:01.76,0:03:02.81,Default,,0000,0000,0000,,看这儿
Dialogue: 0,0:03:02.84,0:03:06.38,Default,,0000,0000,0000,,这就是咱们的pOH嘛
Dialogue: 0,0:03:06.43,0:03:09.19,Default,,0000,0000,0000,,就是氢氧根浓度的负对数
Dialogue: 0,0:03:09.22,0:03:12.88,Default,,0000,0000,0000,,当然喇 它的浓度也是10^(-7)
Dialogue: 0,0:03:12.92,0:03:16.92,Default,,0000,0000,0000,,所以咱们的pOH等于负的浓度的对数-7
Dialogue: 0,0:03:16.97,0:03:18.19,Default,,0000,0000,0000,,把负号提前
Dialogue: 0,0:03:18.23,0:03:19.42,Default,,0000,0000,0000,,pOH等于7
Dialogue: 0,0:03:19.46,0:03:24.48,Default,,0000,0000,0000,,于是你就得到这个pKw的小式子了
Dialogue: 0,0:03:24.51,0:03:28.44,Default,,0000,0000,0000,,或者叫水解离的平衡常数的负对数
Dialogue: 0,0:03:28.49,0:03:32.54,Default,,0000,0000,0000,,pKw等于
Dialogue: 0,0:03:32.58,0:03:41.63,Default,,0000,0000,0000,,水的pH 加上水的pOH
Dialogue: 0,0:03:41.68,0:03:43.56,Default,,0000,0000,0000,,而这个 在25°C
Dialogue: 0,0:03:43.61,0:03:45.28,Default,,0000,0000,0000,,这得是个不变的常数
Dialogue: 0,0:03:45.32,0:03:46.92,Default,,0000,0000,0000,,因为我们要开始捣乱
Dialogue: 0,0:03:46.97,0:03:49.27,Default,,0000,0000,0000,,通过倒点酸或碱到水里头
Dialogue: 0,0:03:49.31,0:03:55.93,Default,,0000,0000,0000,,所以25°C下 pKw为14
Dialogue: 0,0:03:55.97,0:03:57.94,Default,,0000,0000,0000,,记住 只要温度不变
Dialogue: 0,0:03:57.99,0:04:00.46,Default,,0000,0000,0000,,而你又没有对分子做太过分的事
Dialogue: 0,0:04:00.51,0:04:03.50,Default,,0000,0000,0000,,平衡常数就不会变
Dialogue: 0,0:04:03.55,0:04:05.10,Default,,0000,0000,0000,,所以我们才叫它常数嘛
Dialogue: 0,0:04:05.15,0:04:07.33,Default,,0000,0000,0000,,铺垫了半天了
Dialogue: 0,0:04:07.37,0:04:09.96,Default,,0000,0000,0000,,我们快想想如果我倒点酸进去
Dialogue: 0,0:04:10.01,0:04:13.65,Default,,0000,0000,0000,,会发生什么…
Dialogue: 0,0:04:13.69,0:04:16.94,Default,,0000,0000,0000,,假设我放的是盐酸
Dialogue: 0,0:04:16.98,0:04:21.69,Default,,0000,0000,0000,,我换个创意点的颜色写吧
Dialogue: 0,0:04:21.73,0:04:23.66,Default,,0000,0000,0000,,这儿有盐酸
Dialogue: 0,0:04:23.70,0:04:27.23,Default,,0000,0000,0000,,它是个水溶液
Dialogue: 0,0:04:27.27,0:04:31.23,Default,,0000,0000,0000,,我们都知道它是完全电离的
Dialogue: 0,0:04:31.27,0:04:39.24,Default,,0000,0000,0000,,就是说 这儿只剩下氢离子
Dialogue: 0,0:04:39.28,0:04:40.35,Default,,0000,0000,0000,,在这种情况下
Dialogue: 0,0:04:40.40,0:04:43.27,Default,,0000,0000,0000,,它当然是和水分子黏在一块
Dialogue: 0,0:04:43.28,0:04:45.24,Default,,0000,0000,0000,,形成水合氢离子
Dialogue: 0,0:04:45.28,0:04:52.09,Default,,0000,0000,0000,,加上氯离子阴离子 或者叫负离子
Dialogue: 0,0:04:52.13,0:04:54.49,Default,,0000,0000,0000,,就在那儿
Dialogue: 0,0:04:54.53,0:05:09.03,Default,,0000,0000,0000,,假设我放1mol/L的…
Dialogue: 0,0:05:09.07,0:05:10.09,Default,,0000,0000,0000,,或者
Dialogue: 0,0:05:10.14,0:05:12.56,Default,,0000,0000,0000,,有时也可以写成1大写M的\N【译者注：1M=1molar=1mol/L】
Dialogue: 0,0:05:12.60,0:05:14.29,Default,,0000,0000,0000,,盐酸
Dialogue: 0,0:05:14.34,0:05:16.48,Default,,0000,0000,0000,,那么本质上我在干嘛呢？
Dialogue: 0,0:05:16.52,0:05:18.52,Default,,0000,0000,0000,,取1mol/L的盐酸
Dialogue: 0,0:05:18.54,0:05:19.76,Default,,0000,0000,0000,,理论上就是
Dialogue: 0,0:05:19.81,0:05:26.48,Default,,0000,0000,0000,,每升溶液里
Dialogue: 0,0:05:26.52,0:05:28.55,Default,,0000,0000,0000,,有1mol的HCl
Dialogue: 0,0:05:28.57,0:05:29.59,Default,,0000,0000,0000,,主要还是水啦
Dialogue: 0,0:05:29.64,0:05:31.25,Default,,0000,0000,0000,,它是个水溶液嘛
Dialogue: 0,0:05:31.29,0:05:33.56,Default,,0000,0000,0000,,每升水 对吧？
Dialogue: 0,0:05:33.59,0:05:36.26,Default,,0000,0000,0000,,在这儿这些东西的浓度
Dialogue: 0,0:05:36.30,0:05:37.86,Default,,0000,0000,0000,,会变成多少呢？
Dialogue: 0,0:05:37.90,0:05:38.70,Default,,0000,0000,0000,,特别是
Dialogue: 0,0:05:38.74,0:05:41.96,Default,,0000,0000,0000,,氢的浓度 会变成多少？
Dialogue: 0,0:05:42.00,0:05:46.73,Default,,0000,0000,0000,,嗯… 它完全电离 对吧？
Dialogue: 0,0:05:46.75,0:05:47.89,Default,,0000,0000,0000,,所以这个全部…
Dialogue: 0,0:05:47.93,0:05:49.63,Default,,0000,0000,0000,,这不是可逆平衡反应
Dialogue: 0,0:05:49.68,0:05:52.62,Default,,0000,0000,0000,,注意 我只画了单向的箭头指着右边
Dialogue: 0,0:05:52.66,0:05:54.69,Default,,0000,0000,0000,,连个很小的左箭头都没有
Dialogue: 0,0:05:54.74,0:05:57.66,Default,,0000,0000,0000,,盐酸是个强酸
Dialogue: 0,0:05:57.70,0:06:00.52,Default,,0000,0000,0000,,那么如果溶液中有
Dialogue: 0,0:06:00.55,0:06:02.78,Default,,0000,0000,0000,,1mol/L的HCl
Dialogue: 0,0:06:02.82,0:06:04.11,Default,,0000,0000,0000,,你不会找到任何这个
Dialogue: 0,0:06:04.15,0:06:05.22,Default,,0000,0000,0000,,你只能看到这些
Dialogue: 0,0:06:05.27,0:06:11.01,Default,,0000,0000,0000,,所以溶液中氢离子的浓度
Dialogue: 0,0:06:11.05,0:06:16.64,Default,,0000,0000,0000,,就等于1mol/L
Dialogue: 0,0:06:16.68,0:06:20.08,Default,,0000,0000,0000,,当然溶液里面还有1mol/L的氯离子
Dialogue: 0,0:06:20.13,0:06:21.21,Default,,0000,0000,0000,,不过不用管它
Dialogue: 0,0:06:21.24,0:06:23.84,Default,,0000,0000,0000,,如果我之前没提水会电离
Dialogue: 0,0:06:23.87,0:06:25.37,Default,,0000,0000,0000,,那么很容易就能算出来
Dialogue: 0,0:06:25.39,0:06:27.75,Default,,0000,0000,0000,,这个溶液的pH
Dialogue: 0,0:06:27.80,0:06:30.07,Default,,0000,0000,0000,,现在盐酸已经倒进去了
Dialogue: 0,0:06:30.12,0:06:35.98,Default,,0000,0000,0000,,而pH就表示氢离子的浓度
Dialogue: 0,0:06:36.03,0:06:39.12,Default,,0000,0000,0000,,又已知氢离子的浓度了
Dialogue: 0,0:06:39.16,0:06:42.51,Default,,0000,0000,0000,,就是1molar 或者说1mol/L
Dialogue: 0,0:06:42.55,0:06:49.04,Default,,0000,0000,0000,,那么pH就会等于
Dialogue: 0,0:06:49.08,0:06:55.16,Default,,0000,0000,0000,,氢离子浓度的以10为底的负对数
Dialogue: 0,0:06:55.21,0:06:56.36,Default,,0000,0000,0000,,浓度是1
Dialogue: 0,0:06:56.41,0:06:59.38,Default,,0000,0000,0000,,10的几次方等于1呢？
Dialogue: 0,0:06:59.42,0:07:02.53,Default,,0000,0000,0000,,嗯 任何数的0次方都等于1
Dialogue: 0,0:07:02.57,0:07:03.47,Default,,0000,0000,0000,,10也是
Dialogue: 0,0:07:03.51,0:07:06.00,Default,,0000,0000,0000,,因为0的负数就是0
Dialogue: 0,0:07:06.04,0:07:07.83,Default,,0000,0000,0000,,所以你的pH就是0
Dialogue: 0,0:07:07.85,0:07:15.02,Default,,0000,0000,0000,,如果这儿有1mol/L的盐酸
Dialogue: 0,0:07:15.06,0:07:19.45,Default,,0000,0000,0000,,你把它都倒进水溶液里
Dialogue: 0,0:07:19.49,0:07:20.92,Default,,0000,0000,0000,,啊 我意思是说
Dialogue: 0,0:07:20.96,0:07:22.79,Default,,0000,0000,0000,,当我说1mol/L时
Dialogue: 0,0:07:22.83,0:07:23.93,Default,,0000,0000,0000,,就表示已经放进去了
Dialogue: 0,0:07:23.98,0:07:28.19,Default,,0000,0000,0000,,那么如果溶液的浓度是1mol/L
Dialogue: 0,0:07:28.23,0:07:30.97,Default,,0000,0000,0000,,溶剂是水
Dialogue: 0,0:07:31.01,0:07:33.45,Default,,0000,0000,0000,,它的pH就是0
Dialogue: 0,0:07:33.50,0:07:35.34,Default,,0000,0000,0000,,这pH是0
Dialogue: 0,0:07:35.36,0:07:45.12,Default,,0000,0000,0000,,没有任何酸在里面的水 pH等于7
Dialogue: 0,0:07:45.16,0:07:49.87,Default,,0000,0000,0000,,我们把这个pH值称为中性
Dialogue: 0,0:07:49.91,0:07:54.42,Default,,0000,0000,0000,,现在我们就假设有
Dialogue: 0,0:07:54.47,0:07:59.18,Default,,0000,0000,0000,,1mol/L的盐酸 我们可以说…
Dialogue: 0,0:07:59.23,0:08:01.04,Default,,0000,0000,0000,,我用红色吧 因为…
Dialogue: 0,0:08:01.08,0:08:08.45,Default,,0000,0000,0000,,可以说水中的HCl的pH等于0
Dialogue: 0,0:08:08.49,0:08:12.00,Default,,0000,0000,0000,,所以很明显pH越低酸性越强
Dialogue: 0,0:08:12.04,0:08:15.12,Default,,0000,0000,0000,,我们已经在前面的视频里讲过了
Dialogue: 0,0:08:15.16,0:08:18.54,Default,,0000,0000,0000,,现在我们算一下盐酸的pOH是多少
Dialogue: 0,0:08:18.59,0:08:25.39,Default,,0000,0000,0000,,水溶液中的盐酸的pOH
Dialogue: 0,0:08:25.44,0:08:28.97,Default,,0000,0000,0000,,嗯 这得回到勒夏特列原理 对吧？
Dialogue: 0,0:08:29.01,0:08:30.63,Default,,0000,0000,0000,,回想一下之前提到的
Dialogue: 0,0:08:30.68,0:08:34.73,Default,,0000,0000,0000,,这里只有纯水
Dialogue: 0,0:08:34.77,0:08:37.92,Default,,0000,0000,0000,,如果把1mol/L的盐酸放进来
Dialogue: 0,0:08:37.97,0:08:43.93,Default,,0000,0000,0000,,本质上我们就是把一堆
Dialogue: 0,0:08:43.98,0:08:47.37,Default,,0000,0000,0000,,质子放进来了
Dialogue: 0,0:08:47.42,0:08:50.68,Default,,0000,0000,0000,,我们大大地增大了氢离子的浓度
Dialogue: 0,0:08:50.73,0:08:52.82,Default,,0000,0000,0000,,那勒夏特列原理就会说 噢
Dialogue: 0,0:08:52.86,0:08:55.30,Default,,0000,0000,0000,,这不就是得要消耗很多氢氧根
Dialogue: 0,0:08:55.34,0:08:57.43,Default,,0000,0000,0000,,反应就得往这个方向移动
Dialogue: 0,0:08:57.48,0:08:59.51,Default,,0000,0000,0000,,这个平衡就会往这个方向移动
Dialogue: 0,0:08:59.54,0:09:00.68,Default,,0000,0000,0000,,不过要记住
Dialogue: 0,0:09:00.72,0:09:03.73,Default,,0000,0000,0000,,水自身电离的浓度只有10的-7次方
Dialogue: 0,0:09:03.77,0:09:07.39,Default,,0000,0000,0000,,我们可是倒了一百万倍…
Dialogue: 0,0:09:07.43,0:09:13.85,Default,,0000,0000,0000,,就是说这只占在千万分之一mol/L
Dialogue: 0,0:09:13.89,0:09:15.95,Default,,0000,0000,0000,,现在我们要倒进去了 多少来着？
Dialogue: 0,0:09:15.99,0:09:18.60,Default,,0000,0000,0000,,10的7次
Dialogue: 0,0:09:18.64,0:09:22.78,Default,,0000,0000,0000,,我们把比那多一千万倍的氢离子
Dialogue: 0,0:09:22.83,0:09:23.96,Default,,0000,0000,0000,,倒进水里
Dialogue: 0,0:09:24.01,0:09:25.84,Default,,0000,0000,0000,,所以氢氧根都被耗光了
Dialogue: 0,0:09:25.88,0:09:26.79,Default,,0000,0000,0000,,可能变成水了
Dialogue: 0,0:09:26.81,0:09:31.50,Default,,0000,0000,0000,,所以氢氧根的浓度降低太多太多
Dialogue: 0,0:09:31.54,0:09:32.80,Default,,0000,0000,0000,,因为我们真的倒了太多了
Dialogue: 0,0:09:32.84,0:09:34.75,Default,,0000,0000,0000,,而这个的浓度会上升
Dialogue: 0,0:09:34.79,0:09:37.31,Default,,0000,0000,0000,,因为它只能消耗一部分氢氧根
Dialogue: 0,0:09:37.35,0:09:38.82,Default,,0000,0000,0000,,这儿并没那么多
Dialogue: 0,0:09:38.86,0:09:41.28,Default,,0000,0000,0000,,这儿只有10^(-7)mol/L
Dialogue: 0,0:09:41.32,0:09:43.51,Default,,0000,0000,0000,,而氢最后还是1mol/L
Dialogue: 0,0:09:43.56,0:09:45.27,Default,,0000,0000,0000,,而如果它最后还是1mol/L
Dialogue: 0,0:09:45.31,0:09:47.52,Default,,0000,0000,0000,,因为10^(-7)mol/L
Dialogue: 0,0:09:47.57,0:09:49.28,Default,,0000,0000,0000,,本质上 你可以看成是
Dialogue: 0,0:09:49.33,0:09:51.08,Default,,0000,0000,0000,,它全都被这东西耗光了
Dialogue: 0,0:09:51.12,0:09:54.20,Default,,0000,0000,0000,,结果OH-的浓度会是多少呢？
Dialogue: 0,0:09:54.24,0:09:55.19,Default,,0000,0000,0000,,嗯… 已知
Dialogue: 0,0:09:55.23,0:10:00.04,Default,,0000,0000,0000,,25°C下水的pKw是14
Dialogue: 0,0:10:00.09,0:10:02.39,Default,,0000,0000,0000,,且水的pKw是等于
Dialogue: 0,0:10:02.43,0:10:05.76,Default,,0000,0000,0000,,溶液的pH 加pOH
Dialogue: 0,0:10:05.80,0:10:12.76,Default,,0000,0000,0000,,而且盐酸pH是0 对吧？
Dialogue: 0,0:10:12.81,0:10:14.90,Default,,0000,0000,0000,,我们有1mol/L的盐酸
Dialogue: 0,0:10:14.95,0:10:18.74,Default,,0000,0000,0000,,那么1mol/L盐酸的pOH就是14
Dialogue: 0,0:10:18.79,0:10:24.31,Default,,0000,0000,0000,,所以咱们这儿的pOH就等于14了
Dialogue: 0,0:10:24.35,0:10:26.07,Default,,0000,0000,0000,,现在我们同样倒点碱进水里
Dialogue: 0,0:10:26.11,0:10:27.77,Default,,0000,0000,0000,,再算一下它的pH是多少
Dialogue: 0,0:10:27.81,0:10:29.03,Default,,0000,0000,0000,,倒一种强碱
Dialogue: 0,0:10:29.08,0:10:31.02,Default,,0000,0000,0000,,我想你会发现它只是反过来
Dialogue: 0,0:10:31.06,0:10:36.21,Default,,0000,0000,0000,,假设有氢氧化钾(KOH)
Dialogue: 0,0:10:36.25,0:10:37.91,Default,,0000,0000,0000,,这是个强碱
Dialogue: 0,0:10:37.95,0:10:44.10,Default,,0000,0000,0000,,所以它会在水里完全电离成钾离子
Dialogue: 0,0:10:44.14,0:10:46.59,Default,,0000,0000,0000,,带正电
Dialogue: 0,0:10:46.62,0:10:50.59,Default,,0000,0000,0000,,加上氢氧根离子
Dialogue: 0,0:10:50.63,0:10:51.93,Default,,0000,0000,0000,,它会完全电离
Dialogue: 0,0:10:51.96,0:10:53.86,Default,,0000,0000,0000,,如果这些全都在水溶液里
Dialogue: 0,0:10:53.90,0:10:55.44,Default,,0000,0000,0000,,我写下来吧
Dialogue: 0,0:10:55.49,0:11:02.98,Default,,0000,0000,0000,,水溶液 顾名思义就是在水里头 这不用说~
Dialogue: 0,0:11:03.00,0:11:05.95,Default,,0000,0000,0000,,然后假设放1mol/L
Dialogue: 0,0:11:06.00,0:11:07.52,Default,,0000,0000,0000,,记住 浓度很重要
Dialogue: 0,0:11:07.56,0:11:09.73,Default,,0000,0000,0000,,你不能光说 哦 盐酸的pH就是0
Dialogue: 0,0:11:09.78,0:11:10.60,Default,,0000,0000,0000,,不行
Dialogue: 0,0:11:10.64,0:11:14.14,Default,,0000,0000,0000,,你得说1mol/L盐酸 pH是0
Dialogue: 0,0:11:14.18,0:11:15.75,Default,,0000,0000,0000,,实际上我刚才也没写出来
Dialogue: 0,0:11:15.79,0:11:19.78,Default,,0000,0000,0000,,我在这写一下吧 1mol/L
Dialogue: 0,0:11:19.82,0:11:20.85,Default,,0000,0000,0000,,留给你们自己算算
Dialogue: 0,0:11:20.90,0:11:24.79,Default,,0000,0000,0000,,2mol/L的盐酸的pH和pOH是多少
Dialogue: 0,0:11:24.84,0:11:27.29,Default,,0000,0000,0000,,或者取10mol/L的盐酸
Dialogue: 0,0:11:27.34,0:11:30.27,Default,,0000,0000,0000,,给你们算算它的pH
Dialogue: 0,0:11:30.32,0:11:39.88,Default,,0000,0000,0000,,回过头来 我们有1mol/L氢氧化钾
Dialogue: 0,0:11:39.92,0:11:41.27,Default,,0000,0000,0000,,1mol/L这个
Dialogue: 0,0:11:41.31,0:11:43.38,Default,,0000,0000,0000,,它在水里完全电离
Dialogue: 0,0:11:43.42,0:11:46.55,Default,,0000,0000,0000,,啥都不剩
Dialogue: 0,0:11:46.59,0:11:50.91,Default,,0000,0000,0000,,那么OH-的的浓度是多少呢？
Dialogue: 0,0:11:50.93,0:11:55.08,Default,,0000,0000,0000,,OH-的浓度是1mol/L
Dialogue: 0,0:11:55.13,0:11:56.52,Default,,0000,0000,0000,,对吧？
Dialogue: 0,0:11:56.56,0:11:58.11,Default,,0000,0000,0000,,如果你有1mol/L这个
Dialogue: 0,0:11:58.15,0:11:59.44,Default,,0000,0000,0000,,就有1mol/L这个
Dialogue: 0,0:11:59.48,0:12:01.70,Default,,0000,0000,0000,,因为这个在水里全都没了
Dialogue: 0,0:12:01.74,0:12:04.71,Default,,0000,0000,0000,,那么pOH是多少？
Dialogue: 0,0:12:04.75,0:12:08.62,Default,,0000,0000,0000,,pOH就是这个的负对数
Dialogue: 0,0:12:08.67,0:12:10.93,Default,,0000,0000,0000,,1的对数是0
Dialogue: 0,0:12:10.96,0:12:13.23,Default,,0000,0000,0000,,0的负数还是0
Dialogue: 0,0:12:13.27,0:12:18.44,Default,,0000,0000,0000,,然后在这种情况下你的pH
Dialogue: 0,0:12:18.48,0:12:19.79,Default,,0000,0000,0000,,嗯… 你可能会说
Dialogue: 0,0:12:19.83,0:12:21.03,Default,,0000,0000,0000,,哦 它不就是氢的浓度嘛
Dialogue: 0,0:12:21.07,0:12:22.83,Default,,0000,0000,0000,,虽然你并不知道氢离子的浓度是多少
Dialogue: 0,0:12:22.87,0:12:24.86,Default,,0000,0000,0000,,但你知道当你倒了一堆这个后
Dialogue: 0,0:12:24.91,0:12:26.26,Default,,0000,0000,0000,,它就会消耗一堆氢离子
Dialogue: 0,0:12:26.29,0:12:27.60,Default,,0000,0000,0000,,所以氢离子就会减少很多
Dialogue: 0,0:12:27.64,0:12:28.69,Default,,0000,0000,0000,,于是你可能会问 嗯… 那要怎么算？
Dialogue: 0,0:12:28.72,0:12:30.00,Default,,0000,0000,0000,,好吧 你记得吧
Dialogue: 0,0:12:30.03,0:12:33.31,Default,,0000,0000,0000,,25°C
Dialogue: 0,0:12:33.35,0:12:34.95,Default,,0000,0000,0000,,水的平衡常数
Dialogue: 0,0:12:34.99,0:12:37.59,Default,,0000,0000,0000,,等于pH加pOH
Dialogue: 0,0:12:37.63,0:12:39.33,Default,,0000,0000,0000,,我们在视频一开始就铺垫了
Dialogue: 0,0:12:39.37,0:12:43.74,Default,,0000,0000,0000,,所以14就等于pH加上0
Dialogue: 0,0:12:43.76,0:12:45.86,Default,,0000,0000,0000,,0就是这里的pOH
Dialogue: 0,0:12:45.91,0:12:49.62,Default,,0000,0000,0000,,所以pH就是14
Dialogue: 0,0:12:49.66,0:12:51.20,Default,,0000,0000,0000,,那如果你有1mol/L…
Dialogue: 0,0:12:51.24,0:12:53.54,Default,,0000,0000,0000,,这里我用了氢氧化钾
Dialogue: 0,0:12:53.58,0:12:56.15,Default,,0000,0000,0000,,不过如果你有1mol/L的强碱
Dialogue: 0,0:12:56.19,0:12:57.84,Default,,0000,0000,0000,,我写一下这个
Dialogue: 0,0:12:57.88,0:13:05.93,Default,,0000,0000,0000,,1mol/L的强碱
Dialogue: 0,0:13:05.97,0:13:08.60,Default,,0000,0000,0000,,记住 强在化学里是个正式的术语
Dialogue: 0,0:13:08.64,0:13:11.35,Default,,0000,0000,0000,,表示完全电离
Dialogue: 0,0:13:11.39,0:13:18.51,Default,,0000,0000,0000,,这儿pH为14 pOH为0
Dialogue: 0,0:13:18.56,0:13:22.97,Default,,0000,0000,0000,,如果是1mol/L的强酸
Dialogue: 0,0:13:23.01,0:13:25.86,Default,,0000,0000,0000,,如果某人声称自己有pH是0的东西
Dialogue: 0,0:13:25.90,0:13:29.13,Default,,0000,0000,0000,,而且他们打算丢给你
Dialogue: 0,0:13:29.17,0:13:32.10,Default,,0000,0000,0000,,你就应该谢绝或逃离
Dialogue: 0,0:13:32.14,0:13:35.84,Default,,0000,0000,0000,,因为这很可能会伤害你的…
Dialogue: 0,0:13:35.89,0:13:37.82,Default,,0000,0000,0000,,呃 跑题了
Dialogue: 0,0:13:37.87,0:13:39.85,Default,,0000,0000,0000,,假设有1mol/L强酸
Dialogue: 0,0:13:39.89,0:13:47.94,Default,,0000,0000,0000,,其pH为0 pOH为14
Dialogue: 0,0:13:47.98,0:13:50.22,Default,,0000,0000,0000,,反正在下集我就会好好演示
Dialogue: 0,0:13:50.24,0:13:52.58,Default,,0000,0000,0000,,可能会让你有一个印象
Dialogue: 0,0:13:52.63,0:13:54.28,Default,,0000,0000,0000,,知道这是个绝对标度
Dialogue: 0,0:13:54.32,0:13:56.59,Default,,0000,0000,0000,,这儿0就是你得到的酸度
Dialogue: 0,0:13:56.63,0:13:59.07,Default,,0000,0000,0000,,14是通过pH计算得来的碱度
Dialogue: 0,0:13:59.11,0:14:00.45,Default,,0000,0000,0000,,不过这不是重点
Dialogue: 0,0:14:00.49,0:14:01.79,Default,,0000,0000,0000,,实际上可能比这高
Dialogue: 0,0:14:01.83,0:14:02.94,Default,,0000,0000,0000,,也可能比这低
Dialogue: 0,0:14:02.99,0:14:07.62,Default,,0000,0000,0000,,刚才那个例子是1mol/L强酸
Dialogue: 0,0:14:07.66,0:14:09.76,Default,,0000,0000,0000,,假设现在是2mol/L的强酸
Dialogue: 0,0:14:09.80,0:14:11.95,Default,,0000,0000,0000,,或者其实是10mol/L
Dialogue: 0,0:14:11.99,0:14:12.84,Default,,0000,0000,0000,,可以吧？
Dialogue: 0,0:14:12.88,0:14:18.60,Default,,0000,0000,0000,,假设氢的浓度是10mol/L
Dialogue: 0,0:14:18.64,0:14:21.99,Default,,0000,0000,0000,,如果把10mol/L的强酸
Dialogue: 0,0:14:22.04,0:14:24.36,Default,,0000,0000,0000,,加进水溶液里
Dialogue: 0,0:14:24.41,0:14:27.21,Default,,0000,0000,0000,,我用mol/L 说明加了以后浓度是10
Dialogue: 0,0:14:27.25,0:14:29.27,Default,,0000,0000,0000,,那pH是多少？
Dialogue: 0,0:14:29.32,0:14:32.78,Default,,0000,0000,0000,,就等于10的以10为底的负对数
Dialogue: 0,0:14:32.82,0:14:34.91,Default,,0000,0000,0000,,10的常用对数 就是1
Dialogue: 0,0:14:34.95,0:14:36.77,Default,,0000,0000,0000,,10的1次方
Dialogue: 0,0:14:36.81,0:14:38.32,Default,,0000,0000,0000,,所以这个对数等于-1
Dialogue: 0,0:14:38.36,0:14:39.98,Default,,0000,0000,0000,,所以pH等于1
Dialogue: 0,0:14:39.99,0:14:41.67,Default,,0000,0000,0000,,如果有10mol/L的
Dialogue: 0,0:14:41.71,0:14:45.53,Default,,0000,0000,0000,,盐酸或硝酸 或类似的东西
Dialogue: 0,0:14:45.57,0:14:47.49,Default,,0000,0000,0000,,好了 这集到此为止
Dialogue: 0,0:14:47.53,0:14:49.07,Default,,0000,0000,0000,,下集见