物质的化学性质

Lesson Objectives
::经验教训目标

• Describe the chemical properties and types of changes of matter.
  ::描述化学特性和物质变化的类型。

• Describe how to recognize and observe chemical changes of matter.
  ::描述如何识别和观察物质的化学变化。

• Describe reactivity of matter.
  ::描述物质反应。

• Describe flammability of matter.
  ::描述物质的易燃性。

Lesson Vocabulary
::词汇表课程

• chemical property
  ::化学财产的化学财产

• reactivity
  ::对动

• flammability
  ::易燃性

Introduction
::导言

Look at the two garden trowels pictured here. Both trowels were left outside for several weeks. One tool became rusty. The other did not. The tool that rusted is made of iron. The other tool is made of aluminum. The ability to rust is a chemical property. Iron will rust but aluminum will not. 
::看看这幅图上的两块花园的花纹。两块的花纹都留在外面几个星期。一个工具生锈了,另一个没有。生锈的工具是铁制的。另一个工具是铝制的。生锈的能力是化学特性。铁将生锈,但铝不会生锈。

What Are Chemical Properties?
::什么是化学属性?

You have already learned about the physical properties of matter. You may recall that physical properties can be measured and observed. You are able to use your senses to observe and measure them. You can easily tell if something is a certain color. You can tell what state it is in, whether solid, liquid, or gas. You can run tests to see if it conducts electricity. Also, physical changes occur without matter becoming something else. If you tear a piece of paper, each piece is still paper. Do you think this holds true for chemical properties? 
::您已经了解物质物理属性。 您可能记得物理属性是可以测量和观察的。 您可以使用感官来观察和测量它们。 您可以很容易地辨别某物是否为某种颜色。 您可以辨别它在固体、 液体或气体中的状态。 您可以测试它是否进行电力操作。 另外, 物理变化会发生, 而不会变成其它东西。 如果您撕破一块纸, 每一块还是纸。 您认为这对化学特性来说是真实的吗 ?

Chemical properties  can also be measured or observed. This is where the similarity ends. You can only see chemical properties when matter undergoes a change. This change results in an entirely different kind of matter. For example, the ability of iron to rust can only be observed after it rusts. The shiny piece of metal gives no clue to whether it will rust or not until it does. But what is rust? When iron rusts, it combines with oxygen. Iron and oxygen is new substance, called iron oxide. It is no longer just iron. It has undergone a change. It is now a different substance. Iron is very hard and silver in color. In contrast, iron oxide is flakey and reddish brown. The ability to rust is only one type of chemical property. 
::也可以测量或观测化学特性。 这是相似性结束的地方。 您只能在物质发生变化时看到化学特性。 这种变化导致完全不同的物质。 例如, 铁的生锈能力只有在生锈之后才能观察到。 闪亮的金属块在生锈之前无法说明它是否会生锈。 但是什么是生锈? 当铁锈的时候, 它会与氧气结合在一起。 铁和氧气是新物质, 被称为氧化铁。 它不再只是铁。 它已经发生了改变。 它现在是一个不同的物质。 铁是非常硬的, 银色是颜色的。 相反, 铁氧化物是粉状的, 红褐色的。 生锈的能力只是一种化学特性。

Reactivity
::反应

Reactivity  is another type of chemical property. Reactivity is the ability of matter to combine chemically with other substances. Some kinds of matter are extremely reactive. Others kinds of matter are extremely unreactive. Have you ever mixed baking soda with vinegar in your science class? If you have, you have seen an interesting reaction. Please do not try this at home without supervision. Vinegar and baking soda both have the chemical property that causes them to react with each other. Other substances are very unreactive. 
::反应是另一种化学特性。 反应是物质与其他物质化学结合的能力。 有些物质反应性极强。 其它物质反应性极强。 您是否在科学课中将苏打和醋混合过? 如果有的话, 您已经看到了一种有趣的反应。 请不要在没有监督的情况下在家里尝试。 醋和苏打都具有导致它们相互反应的化学特性。 其他物质是非常不反应的。

Flammability
::易燃

Have you ever seen a symbol that says "Flammable"? You might see such a symbol on a gasoline can. Gasoline is highly flammable. That is why there are signs at the gas station that say, "NO SMOKING."
::你有没有见过一个符号 上面写着"可燃"?

Flammability  is the ability of matter to burn. When matter burns, it combines with oxygen. When it does, it changes to different substances. Wood is an example of flammable matter, as seen in  Figure   .
::易燃性是燃烧物质的能力。当物质燃烧时,它与氧气结合。当燃烧时,它会改变为不同的物质。木是易燃物质的例子,如图中所示。

Q:  How can you tell that wood ashes are a different substance than wood?
::问题:你如何知道木灰与木灰是不同的物质?

A:  Ashes have different properties than wood. For example, ashes are gray and powdery. Wood is brown and hard.
::甲:灰灰与木有不同特性,例如灰灰和灰粉。木是棕色和硬的。

Q:  What are some other substances that have the property of flammability?
::问题:哪些其他物质具有易燃性特性?

A:  Substances called fuels have the property of flammability. They include fossil fuels such as coal, natural gas, and petroleum. For example, gasoline is used in our cars because it is flammable. This property enables car engines to run. Substances made of wood, such as paper and cardboard, are also flammable.
::A: 称为燃料的物质具有易燃性特性,包括煤炭、天然气和石油等化石燃料,例如,汽油在我们的汽车中使用,因为汽油易燃,使汽车发动机能够运行,用木制物质,如纸板和纸板也易燃。

Lesson Summary
::经验教训摘要

• Chemical properties and physical properties are properties that can be measured or observed. They can only be measured or observed when matter undergoes a change to become an entirely different kind of matter.
  ::化学特性和物理特性是可以测量或观测的特性,只有在物质发生改变成为完全不同的物质时才能测量或观测。

• Chemical properties include reactivity, flammability, and the ability to rust.
  ::化学特性包括活性、易燃性和生锈能力。

• Reactivity is the ability of matter to react chemically with other substances.
  ::反应是物质与其他物质进行化学反应的能力。

• Flammability is the ability of matter to burn.
  ::易燃性是物质燃烧的能力。

Lesson Review
::经验教训审查

1. What is a chemical property?
   ::什么是化学财产?

1. Define the chemical property called reactivity.
   ::定义称为反应的化学属性。

1. What is flammability? Identify examples of flammable matter.
   ::什么是易燃性?查明易燃物质的例子。