10.3 摩拉弥撒

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  摩拉尔弥撒

  

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  When creating a solution, how do I know how much of each substance to put in?
  ::在创造解决办法时,我怎么知道需要投入多少物质?

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  I want to make a solution that contains 1.8 moles of potassium dichromate.  I don’t have a balance calibrated in molecules, but I do have one calibrated in grams.  If I know the relationship between moles and the number of grams in a mole, I can use my balance to measure out the needed amount of material.
  ::我想找到一个包含1.8个硝酸钾二酸钾摩尔的解决方案。 我对分子没有进行平衡校准,但我确实有一个以克为单位的校准。 如果我知道摩尔和摩尔的克数之间的关系,我可以用平衡来衡量所需材料的数量。

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  Molar Mass
  ::摩拉尔弥撒

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  Molar mass is defined as the mass of one mole of representative particles of a substance . By looking at a periodic table , we can conclude that the molar mass of lithium is 6.94 g, the molar mass of zinc is 65.38 g, and the molar mass of gold is 196.97 g.  Each of these quantities contains 6.02 × 10 ²³ atoms of that particular .  The units for molar mass are grams per mole or g/mol.
  ::摩尔质量的定义是物质具有代表性粒子的一个摩尔质量。通过查看一个周期表,我们可以得出以下结论:锂的摩尔质量为6.94克,锌的摩尔质量为65.38克,金的摩尔质量为196.97克。这些数量中每一数量含有该特定物质的6.02×1023原子。摩尔质量的单位为每摩尔克或克/摩尔。

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  Molar Masses of Compounds
  ::化合物的摩拉质质量

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  A of the carbon dioxide is CO ₂ .  One molecule of carbon dioxide consists of 1 of carbon and 2 atoms of oxygen.  We can calculate the mass of one molecule of carbon dioxide by adding together the masses of 1 atom of carbon and 2 atoms of oxygen.
  ::一个二氧化碳分子由1个碳原子和2个氧原子组成。我们可以将1个碳原子和2个氧原子相加,从而计算一个二氧化碳分子的质量。

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  $$\begin{array}{r}12.01\text{amu}+2(16.00\text{amu})=44.01\text{amu}\end{array}$$

  
  ::12.01 amu+2(16.00 amu)=44.01 amu

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  The molecular mass of a compound is the mass of one molecule of that compound.  The molecular mass of carbon dioxide is 44.01 amu.
  ::化合物的分子质量是该化合物的一个分子的质量,二氧化碳的分子质量是44.01 amu。

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  The molar mass of any compound is the mass in grams of one mole of that compound.  One mole of carbon dioxide molecules has a mass of 44.01 g, while one mole of sodium sulfide formula units has a mass of 78.04 g.  The molar masses are 44.01 g/mol and 78.04 g/mol respectively.  In both cases, that is the mass of 6.02 × 10 ²³ representative particles.  The representative particle of CO ₂ is the molecule, while for Na ₂ S, it is the formula unit.
  ::任何化合物的摩尔质量是该化合物中一种摩尔质量的克,一种二氧化碳分子的摩尔质量为44.01克,而一种硫化钠配方单位的摩尔质量为78.04克。摩尔质量分别为44.01克/摩尔和78.04克/摩尔。在这两种情况下,摩尔质量为6.02×1023具有代表性的粒子。具有代表性的CO2粒子是分子,而在Na2S,它是配方单位。

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  Sample Problem:  Molar Mass of  a Compound
  ::问题:一个化合物的摩尔质量

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  Calcium nitrate, Ca(NO ₃ ) ₂ , is used as a component in fertilizer Determine the molar mass of calcium nitrate.
  ::硝酸钙,Ca(NO3)2,用作化肥的一个成分,确定硝酸钙的摩尔质量。

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  Step 1:  List the known and unknown quantities and plan the problem.
  ::第1步:列出已知和未知的数量并规划问题。

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  Known
  ::已知已知

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  • formula = Ca(NO ₃ ) ₂
    ::公式 = Ca( NO3) 2
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  • molar mass Ca = 40.08 g/mol
    ::摩拉质量卡=40.08克/摩尔
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  • molar mass N = 14.01 g/mol
    ::摩尔质量N=14.01克/摩尔
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  • molar mass O = 16.00 g/mol
    ::摩拉质量O = 16.00克/摩尔

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  Unknown
  ::未知

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  • molar mass Ca(NO ₃ ) ₂
    ::Ca(NO3) 2 摩尔质量

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  First we need to analyze the formula.  Since the Ca lacks a subscript, there is one Ca atom per formula unit.  The 2 outside the parentheses means that there are two nitrate per formula unit and each nitrate ion consists of one nitrogen atom and three oxygen atoms.  Therefore, there are a total of 1 × 2 = 2 nitrogen atoms and 3 × 2 = 6 oxygen atoms per formula unit.  Thus, 1 mol of calcium nitrate contains 1 mol of Ca atoms, 2 mol of N atoms, and 6 mol of O atoms.
  ::首先,我们需要分析公式。 由于 Ca 缺乏下标, 每个公式单位有一个原子。 括号外的 2 表示每个公式单位有两个硝酸盐, 每个硝酸盐离子由1个氮原子和3个氧原子组成。 因此, 总共是 1 × 2 = 2 氮原子, 3 × 2 = 6 氧原子。 因此, 1 毫升硝酸钙包含 1 毫升的碳原子, 2 毫升的N原子, 6 毫升的O原子。

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  Step 2:  Calculate.
  ::第2步:计算。

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  Use the molar masses of each atom together with the number of atoms in the formula and add together.
  ::使用每个原子的摩尔质量,同时使用公式中的原子数量并加在一起。

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  $$\begin{array}{rl}& 1\text{mol Ca}\times \frac{40.08\text{g Ca}}{1\text{mol Ca}}=40.08\text{g Ca}\\ & 2\text{mol N}\times \frac{14.01\text{g N}}{1\text{mol N}}=28.02\text{g N}\\ & 6\text{mol O}\times \frac{16.00\text{g O}}{1\text{mol O}}=96.00\text{g O}\\ & \text{molar mass of }{\text{Ca(NO}}_3{)}_2=40.08\text{g}+28.02\text{g}+96.00\text{g}=164.10\text{g}/\text{mol}\end{array}$$

  
  ::1 mol Cax40.08 g Ca1 mol Ca1 mol Ca1 mol = 40.08 g Ca2 mol Nx14.01 g N1 mol N=28.02 g N6 mol Ox16.00 g O1 mol Ox16.00 g O1 mol O=96.00 g Omolar质量卡卡(NO3)2 = 40.08 g+28.02 g+96.00 g=164.10 g/mol

   

   

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  Summary
  ::摘要

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  • Calculations are described for the determination of molar mass of an atom or a compound.
    ::为确定原子或化合物的摩尔质量而说明了计算方法。

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  Review
  ::回顾

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  1. What is the molar mass of Pb?
     ::PB的摩尔质量是什么?
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  2. Where do you find the molar mass of an element?
     ::你在哪里找到一个元素的摩尔质量?
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  3. How many moles of Cl are in one mole of the CaCl ₂ ?
     ::CACL2的一粒内有几颗内鬼?
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  4. How many moles of H are in  one mole of the  compound (NH ₄ ) ₃ PO ₄ ?
     ::化合物(NH4)3PO4的一介分子中有多少H的摩尔?
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  5. Calculate the molar mass of CaCl ₂ .
     ::计算 CaCl2 的摩尔质量。