溶解速率

Lesson Objective
::经验教训目标

• Identify the conditions that will speed up or slow down the dissolving process. 
  ::确定加快或减缓解体进程的条件。

Lesson Vocabulary
::词汇表课程

• dissolve
  ::溶解

• mixture
  ::混合混合物

• solution
  ::解决方案

Introduction
::导言

 

Do you prefer your iced tea sweetened with sugar? Sweetened iced tea is a solution. The solid sugar (the solute) is dissolved in cold liquid tea. The liquid tea is mostly water (the solvent). What do you think happens when you add sugar to tea? Particles of water pull apart particles of sugar. The particles of sugar spread throughout the tea. This is what makes the tea taste so good.
::你更喜欢用糖来加糖的冰茶吗?甜甜的冰茶是一个解决办法。软糖(溶液)溶解在冷液茶中。液茶主要是水(溶剂)。你在茶里加糖时会怎样?水的粒子将糖的颗粒分离开来。糖的颗粒散布在茶里。茶的味道就是这样的。

Factors That Affect the Rate of Dissolving
::影响解体率的因素

Did you ever drink the tea before all the sugar has dissolved? Did you ever notice that some of the sugar is sitting at the bottom of the glass?
::在糖溶解之前你喝过茶吗?

Q : What could you do to dissolve the sugar faster?
::问:你能做些什么来加快糖溶解速度?

A : The rate of dissolving is caused by several factors. These factors include stirring, temperature, and the size of the particles.
::A: 溶解速度是由若干因素造成的,其中包括振动、温度和粒子大小。

Stirring
::纹理

What would happen if you added sugar to iced tea and did not stir the liquid? That's right, most of the sugar you added would fall to the bottom of the glass. Like most people, when you add sugar to a liquid, you stir it, but why? For most of us, it is automatic. How many times have you added something to a liquid and immediately grabbed our spoon and started to stir. Have you ever thought about why we stir? So, why do we stir liquids when we add other ingredients? 
::如果你在冰茶中加糖,而不搅拌液体,那会怎样呢?你说的对,你加的糖大部分会倒在玻璃的底部。和大多数人一样,当你把糖加在液体中的时候,你会搅拌它,但为什么呢?对于我们大多数人来说,它是自动的。你把糖加在液体中,然后立刻抓住我们的勺子,然后开始搅拌。你有没有想过我们为什么要搅拌?所以,我们加其他成分的时候,为什么要搅拌液体呢?

Stirring a liquid while you are mixing in another ingredient speeds up the rate of dissolving. This is because it helps distribute the particles that are being dissolved. What happens when you add sugar (the solute) to iced tea (the solvent) and then stir the tea? The obvious answer is that the sugar will dissolve. The more quickly you stir, the faster the sugar will dissolve. What if you don't stir the tea? Will the sugar still dissolve? It may eventually dissolve, but it will take much longer. You can think of stirring like adding energy to the process. What are other ways to add energy? 
::当您在另一种成分中混合时, 搅拌液体会加速溶解速度。 这是因为它有助于分配溶解的粒子。 当你在冰茶中添加糖( 溶液) , 然后搅拌茶时会怎样? 显而易见的答案是糖会溶解。 你越快搅拌, 糖就会越快溶解。 如果你不搅拌茶, 糖会溶解吗? 糖会继续溶解吗? 它可能最终溶解, 但它会花更长的时间。 您可以想象为这一过程添加能量。 增加能量的其他方法是什么?

Temperature
::温度

What do you think will happen when you add the same amount of sugar to cups of hot and cold tea?  Will the sugar dissolve at the same rate? Is that why people start with warm water when they make iced tea? 
::当你把同样数量的糖加到热茶和冷茶杯中时,你会怎样想? 糖会以同样的速度溶解吗? 这就是为什么人们做冰茶时会从热水开始吗?

The temperature of the solvent is an important factor in how fast something dissolves. Temperature affects how fast a solute dissolves. Generally, a solute dissolves faster in a warmer solvent. It dissolves more slowly in a cooler solvent.  Think about that next time you make iced tea. 
::溶剂的温度是某物溶解速度的一个重要因素。 温度影响溶液溶解速度。 一般而言, 溶液溶解速度较快, 溶剂溶解速度较慢, 溶剂溶解速度较慢。 下次你泡冰茶时再考虑一下 。

Particle Size
::粒子大小

There is another factor that affects the rate of dissolving. The particle size of solute particles affects the rate. Smaller particles have greater surface area. Think of a large block of Legos. When all the blocks are stuck together you can measure their surface area. Now take all the blocks apart and measure their individual surface areas. Which has more? Greater surface area provides more contact between the particles and the solvent. For example, if you put granulated sugar in a glass of iced tea, it will dissolve more quickly. If you put a sugar cube in a glass of iced tea, it will dissolve more slowly. That's because all those tiny particles of granulated sugar have greater surface area than a single sugar cube. 
::还有一个影响溶解速度的因素。 溶液粒子的粒子大小会影响速度。 小颗粒有更大的表面面积。 想象一个大块的Legos 。 当所有区块都粘在一起时, 您可以测量它们的表面积。 现在可以将所有区块分开来测量它们各自的表面积。 哪个更多? 更大的表面积可以使粒子和溶剂之间有更多的接触。 例如, 如果将颗粒糖放在冰茶杯中, 它会更快地溶解。 如果您在一个冰茶杯中放一个糖立方块, 它的溶解会更慢。 这是因为这些颗粒糖的微粒面积比一个糖立方还要大。

Lesson Summary
::经验教训摘要

• The rate of dissolving of a solute in a solvent is faster when the solute and solvent are stirred.
  ::当溶剂和溶剂被搅拌时,溶剂溶液溶解速度更快。

• The rate of dissolving is affected if the solute consists of smaller particles with more surface area.
  ::如果溶液由面积更大的小颗粒组成,溶解速度就会受到影响。

Lesson Review
::经验教训审查

1. List three factors that affect the rate at which a solute dissolves in a solvent.
   ::列出影响溶液溶解剂溶解速度的三个因素。

1. Gina is trying to dissolve bath salts in her bathwater. How could she speed up the rate of dissolving?
   ::吉娜试图在浴池里溶解浴盐 她怎么能加速溶解速度呢?