原子质量股

How many gallons of gas can fill a car's tank?
::有多少加仑的汽油能装满一辆汽车的油箱?

The current system of measurement in the Unites States is a hodge-podge of different units, many of which are hard to interconvert, unlike the metric system.  We at least have standardized units these days, unlike centuries past.  At one time, measurements of length often were defined as the distance from the end of one appendage to another.  For example, the yard would be defined as the distance from the king's nose to the tip of his thumb when his arm was stretched out. 
::美国目前的测量系统是不同单位的悬崖边,其中许多单位与衡量系统不同,难以相互转换。我们现在至少有标准化单位,与过去几个世纪不同。有一次,长度的测量常常被定义为从一个附属体的终点到另一个附属体的距离。例如,院子的定义是,在国王手臂伸展时,从国王鼻子到拇指尖的距离。

Standardized measurements make it possible for people everywhere to get the same amount of something.  Note the red and white labels on the pump above.  These labels certify that the gas pump has been checked and is pumping an accurate gallon of gas.  Standard measurements in science are very important so that we can compare experimental data from one lab to another and make sure we all are talking about the same thing.
::标准化测量使得世界各地的人们能够获得同样数量的东西。 注意上面泵上的红白标签。 这些标签证明气泵已经检查过,正在抽出准确的一加仑气体。 科学方面的标准测量非常重要, 以便我们可以将实验数据从一个实验室到另一个实验室进行比较, 确保我们都在谈论同样的事情。

Atomic Mass
::原子原子质量

Masses of individual atoms are very, very small. Using a modern device called a mass spectrometer, it is possible to measure such minuscule masses. An of oxygen-16, for example, has a mass of 2.66 × 10 ^-23 g. While comparisons of masses measured in grams would have some usefulness, it is far more practical to have a system that will allow us to more easily compare relative atomic masses. Scientists decided on using the carbon-12 nuclide as the reference standard by which all other masses would be compared. By definition, one atom of carbon-12 is assigned a mass of 12 atomic mass units (amu). An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12. The mass of any of any is expressed in relation to the carbon-12 standard. For example, one atom of helium-4 has a mass of 4.0026 amu. An atom of sulfur-32 has a mass of 31.972 amu.
::单个原子质量非常小,非常小。 使用称为质谱仪的现代设备,可以测量这种微粒质量。 例如, 氧-16的原子质量为2.66×10-23克。 虽然用克测量的质数比较会有些用处,但更实际的办法是建立一个系统,使我们更容易比较相对原子质量。 科学家决定使用碳-12核素作为参照标准,用以比较所有其他质量。 根据定义,一个碳-12原子原子原子原子质量为12个原子质量单位( AMu) 。 原子质量单位的定义是相当于碳-12原子质量的十二分之一。 任何原子质量都以碳-12标准表示。 例如, 任何原子的-4的原子质量为4. 0026 amu。 硫-32的原子质量为31.972 amu。

The carbon-12 atom has six and six neutrons in its nucleus for a of 12. Since the nucleus accounts for nearly all of the mass of the atom, a single proton or single has a mass of approximately 1 amu. However, as seen by the helium and sulfur examples, the masses of individual atoms are not whole numbers. This is because an atom's mass is affected very slightly by the interactions of the various particles within the nucleus, and the small mass of the is taken into account.
::碳-12原子的核心有6个和6个中子,其核心为12个。由于核心几乎占原子的所有质量,一个质子或单个质子的重量约为1个立方厘米,然而,从氦和硫的示例中可以看出,单个原子的重量并不是整数。这是因为原子的质子受到核内各种颗粒相互作用的轻微影响,而该质子的微量被考虑在内。

Summary
::摘要

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• Carbon-12 is the reference for all atomic mass calculations.
  ::碳-12是所有原子质量计算的基准。
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• An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12.
  ::原子质量单位的定义是等于碳-12原子质量十二分之一的质量。
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• The mass of an atom is affected by the interactions of particles within the nucleus.
  ::原子质量受到核内粒子相互作用的影响。

Review
::回顾

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1. What instrument is used to measure the mass of atoms?
   ::用什么工具测量原子质量?
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2. How much does a single oxygen-16 atom weigh in grams?
   ::一个氧气 -16原子的重量 以克计是多少?
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3. What is the reference standard for atomic mass units?
   ::原子质量单位的参考标准是什么?
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4. How is an atomic mass unit defined?
   ::原子质量单位的定义如何?
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5. Why are the numbers for atomic mass of individual atoms not whole numbers?
   ::为什么单个原子原子的原子质量数字不是全部数字?