Section outline

  • General

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  • 电离测量和热化学等量

    Manufacturing plant emitting smoke, highlighting concerns about pollution and environmental impact.

    What will it cost?
    ::要花多少钱?

    There is a growing concern about the damage to from emissions from manufacturing plants. Many companies are taking steps to reduce these harmful emissions by adding equipment that will trap the pollutants. In order to know what equipment (and how many) to order, studies need to be done to measure the amount of product currently produced. The since pollution is often both particulate and thermal, energy changes need to be determined in addition to the amounts of products released.
    ::许多公司正在采取步骤减少这些有害排放,增加将污染物困住的设备。为了了解需要订购哪些设备(和有多少设备),需要开展研究,以衡量目前生产的产品数量。由于污染往往是颗粒和热的,因此除了释放的产品数量之外,还需要确定能源的变化。

    Stoichiometric Calculations and Enthalpy Changes
    ::斯托光度计算和酶变化

    Chemistry problems that involve changes can be solved by techniques similar to stoichiometry problems.  Refer again to the of methane. Since the reaction of 1 mol of methane released 890.4 kJ, the reaction of 2 mol of methane would release 2 × 890.4  kJ = 1781  kJ . The reaction of 0.5 mol of methane would release 890.4  kJ 2 = 445.2  kJ . As with other stoichiometry problems, the moles of a reactant or product can be linked to mass or volume .
    ::涉及变化的化学问题可以通过类似声学问题的技术来解决。再次参考甲烷。由于1毫升的甲烷释放了890.4千焦耳,2毫升的甲烷反应将释放2×890.4千焦耳。0.5毫升的甲烷反应将释放890.4千焦耳。与其他声学问题一样,反应剂或产品的摩尔可以与质量或体积联系起来。

    Sample Problem: Calculating Enthalpy Changes
    ::样本问题: 计算嵌入器变化

    Sulfur dioxide reacts with oxygen to form sulfur trioxide in an according to the following .
    ::二氧化硫与氧发生反应,形成三氧化硫,如下所示。

    2 SO 2 ( g ) + O 2 ( g ) → 2 SO 3 ( g ) + 198  kJ

    ::2SO2(g)+O2(g)%%2SO3(g)+198千焦耳

    Calculate the enthalpy change that occurs when 58.0 g of sulfur dioxide is reacted with excess oxygen.
    ::计算58.0克二氧化硫与过量氧气发生反应时的变化。

    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

    • mass SO 2 = 58.0 g
      ::质量 SO2 = 58.0克
    • SO 2 = 64.07 g/mol
      ::SO2 = 64.07克/摩尔
    • Δ H = − 198  kJ for the reaction of  2  mol SO 2
      ::H198千焦耳,2 mol SO2的反应

    Unknown
    ::未知

    • Δ H = ?  kJ
      ::H=KJ吗?

    The calculation requires two steps. The mass of SO 2 is converted to moles. Then the mol SO 2 is multiplied by the conversion factor of ( − 198  kJ 2  mol SO 2 ) .
    ::计算需要两个步骤。SO2的质量被转换为摩尔。然后摩尔SO2乘以换算系数(- 198 kJ2 mol SO2)。

    Step 2: Solve .
    ::步骤2:解决。

    Δ H = 58.0  g SO 2 × 1  mol SO 2 64.07  g SO 2 × − 198  kJ 2  mol SO 2 = − 89.6  kJ

    ::* H=5 800 g SO2x1 mol SO264.07 g SO2=198 kJ2 mol SO2=89.6 kJ

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

    The mass of sulfur dioxide is slightly less than 1 mol. Since 198 kJ is released for every 2 mol of SO 2 that reacts, the released when about 1 mol reacts is one half of 198. The 89.6 kJ is slightly less than half of 198. The sign of  Δ H is negative because the reaction is exothermic .
    ::二氧化碳的含量略小于1毫升。 由于每2兆瓦的SO2反应中释放198千焦耳,大约1毫焦耳反应时释放的量为198年的一半。89.6千焦耳略小于198年的一半。ZH的表示为负值,因为反应是过热的。

     

     

    Summary
    ::摘要

    • Calculations of energy changes in enthalpy equations are described.
      ::介绍了对方程式能量变化的计算。

    Review
    ::回顾

    1. What do you need to determine to solve enthalpy stoichiometry problems?
      ::你需要决定什么才能解决 蚂蚁的体外测量问题?
    2. If I react 1.75 moles of methane, how much energy will be involved?
      ::如果我反应 1.75毫摩尔的甲烷, 需要多少能量?
    3. I ran a reaction producing sulfur dioxide and releasing 267.3 kJ of energy. How many moles of sulfur dioxide were involved in the reaction?
      ::我做了一次反应 产生二氧化硫 释放了267.3千焦耳的能量