Section: 稀释 | 16.12 稀释

Section outline

How do you clean concrete?
::你怎么打扫混凝土?

Muriatic (another name for HCl) is widely used for cleaning concrete and masonry surfaces. The acid must be diluted before use to get it down to a safer strength. Commercially available at of about 18%, this can be used to remove scales and deposits (usually composed of basic materials).
::Muriatic(HCl的另一个名称)被广泛用于清理混凝土和泥瓦表面。酸在使用前必须稀释,才能降低到更安全的强度。商业价格约为18%,可用于去除比例尺和矿床(通常由基本材料组成 ) 。

Dilutions
::稀释

When additional water is added to an aqueous solution , the concentration of that solution decreases. This is because the number of moles of the solute does not change, while the volume of the solution increases. We can set up an equality between the moles of the solute before the dilution (1) and the moles of the solute after the dilution (2).
::当添加水溶液时,该溶液的集中度会下降。这是因为溶液的摩尔数量没有变化,而溶液的量却在增加。我们可以在溶液稀释前的摩尔数量(1)和溶液稀释后的摩尔数量(2)之间建立平等关系。

$\begin{aligned} {mol}_{1} = {mol}_{2} \end{aligned}$
$\begin{align*}\text{mol}_1=\text{mol}_2\end{align*}$
::mol1=摩尔2

Since the moles of solute in a solution is equal to the multiplied by the liters , we can set those equal.
::因为溶液溶液中的摩尔等于乘以公升数,我们可以将这些等值设定为等值。

$\begin{aligned} M_{1} \times L_{1} = M_{2} \times L_{2} \end{aligned}$
$\begin{align*}M_1 \times L_1=M_2 \times L_2\end{align*}$
::M1xL1=M2xL2

Finally, because the two sides of the equation are set equal to one another, the volume can be in any units we choose, as long as that unit is the same on both sides. Our equation for calculating the molarity of a diluted solution becomes:
::最后,由于等式的两面是等式的,体积可以是我们选择的任何单位,只要两边的单位相同。我们计算稀释溶液的质度的公式是:

$\begin{aligned} M_{1} \times V_{1} = M_{2} \times V_{2} \end{aligned}$
$\begin{align*}M_1 \times V_1 = M_2 \times V_2\end{align*}$
::M1xV1 = M2xV2

Suppose that you have 100. mL of a 2.0 M solution of HCl. You dilute the solution by adding enough water to make the solution volume 500. mL. The new molarity can easily be calculated by using the above equation and solving for $\begin{align*}M_2\end{align*}$ .
::假设您有 HCl. 2. 0 M 溶液的 100 毫升。您可以通过添加足够的水来稀释溶液, 使溶液体积达到 500. 毫升。新的摩尔度很容易通过使用上述方程和M2的溶解来计算。

$\begin{aligned} M_{2} = \frac{M_{1} \times V_{1}}{V_{2}} = \frac{2.0 M \times 100. mL}{500. mL} = 0.40 M H C l \end{aligned}$
$\begin{align*}M_2=\frac{M_1 \times V_1}{V_2}=\frac{2.0 \text{ M} \times 100. \text{ mL}}{500. \text{ mL}}=0.40 \text{ M } HCl\end{align*}$
::M2=M1xV1V2=2.0Mx100.毫升500.毫升=0.40MHCl

The solution has been diluted by one-fifth since the new volume is five times as great as the original volume. Consequently, the molarity is one-fifth of its original value.
::溶液被稀释了五分之一,因为新卷是原卷的五倍。因此,摩尔度是原值的五分之一。

Another common dilution problem involves deciding how much of a highly concentrated solution is requires to make a desired quantity of solution of lesser concentration. The highly concentrated solution is typically referred to as the stock solution.
::另一个常见的稀释问题涉及决定高度集中的解决方案需要多少才能达到预期的较低集中的解决方案。高度集中的解决方案通常被称为库存解决方案。

Sample Problem: Dilution of a Stock Solution
::样本问题: 解决股票溶液

Nitric acid (HNO ₃ ) is a powerful and corrosive acid. When ordered from a chemical supply company, its molarity is 16 M. How much of the stock solution of nitric acid needs to be used to make 8.00 L of a 0.50 M solution?
::硝酸(HNO3)是一种强力和腐蚀性酸,当化学供应公司订购时,其纯度为16M。硝酸的存货溶液需要用多少来制造0.50M溶液的8.00L?

Step 1: List the known quantities and plan the problem.
::第1步:列出已知数量并规划问题。

Known
::已知已知

stock HNO ₃ = 16 M
::HNO3 = 16米

$\begin{align*}V_2=8.00 \ \text{L}\end{align*}$
::V2=8.00升

$\begin{align*}M_2=0.50 \ \text{M}\end{align*}$
::M2=0.0.50米

Unknown
::未知

$\begin{align*}\text{volume stock} \ \text{HNO}_3 \ (V_1)=? \ \text{L}\end{align*}$
::HNO3(V1)=? L

The unknown in the equation is $\begin{align*}V_1\end{align*}$ , the volume of the concentrated stock solution.
::方程式中未知的是V1,即集中库存溶液的数量。

Step 2: Solve.
::步骤2:解决。

$\begin{aligned} V_{1} = \frac{M_{2} \times V_{2}}{M_{1}} = \frac{0.50 M \times 8.00 L}{16 M} = 0.25 L = 250 mL \end{aligned}$
$\begin{align*}V_1=\frac{M_2 \times V_2}{M_1}=\frac{0.50 \text{ M} \times 8.00 \text{ L}}{16 \text{ M}}=0.25 \text{ L}=250 \text{ mL}\end{align*}$
::V1=M2xV2M1=0.50 Mx8.00 L16 M=0.25 L=250 mL

Step 3: Think about your result.
::步骤3:想想你的结果。

250 mL of the stock HNO ₃ needs to be diluted with water to a final volume of 8.00 L. The dilution is by a factor of 32 to go from 16 M to 0.5 M.
::需要用水冲淡250毫升的HNO3储量,以冲淡至8.00升。稀释的系数为32,从16毫升到0.5毫升。

Dilutions can be performed in the laboratory with various tools, depending on the volumes required and the desired accuracy . The following images illustrate the use of two different types of pipettes. The images below illustrate the use of two different types of pipettes. In the first figure ( Figure ), a glass pipette is being used to transfer a portion of a solution to a volumetric flask. Use of a pipette rather than a graduated cylinder for the transfer improves accuracy. The second figure ( Figure ) shows a micropipette , which is designed to quickly and accurately dispense small volumes. Micropipettes are adjustable and come in a variety of sizes.
::根据所需数量和所需准确度,可在实验室用各种工具进行稀释。以下图像说明了两种不同类型的管道的使用。以下图像说明了两种不同类型的管道的使用。在第一个图(图 ) 中,玻璃管用于将部分溶液转移到一个体积瓶中。使用管道而不是升级的气瓶进行转移可以提高准确性。第二个图(图 ) 显示了一种微气管,其设计是为了迅速和准确地分配少量的管道。微气管可以调整,其尺寸各有不同。

Volumetric pipette.

Micropipette.

Summary
::摘要

A process is described for calculations of dilutions.
::描述一个进程用于计算稀释。

Review
::回顾

What does not change when additional water is added to a solution?
::如果在解决办法中增加额外的水,有什么变化?

What is a stock solution?
::什么是股票解决方案?

How is a stock solution used?
::如何使用股票解决办法?

Section outline

How do you clean concrete? ::你怎么打扫混凝土?

Dilutions ::稀释

Sample Problem: Dilution of a Stock Solution ::样本问题: 解决股票溶液

Summary ::摘要

Review ::回顾

How do you clean concrete?
::你怎么打扫混凝土?

Dilutions
::稀释

Sample Problem: Dilution of a Stock Solution
::样本问题: 解决股票溶液

Summary
::摘要

Review
::回顾