新东方网>留学>SAT考试>SAT辅导>SAT化学>正文

The Ideal Gas Law

2011-09-20 16:43

来源:网络

作者:

  The ideal gas law is the most important gas law for you to know: it combines all of the laws you learned about in this chapter thus far, under a set of standard conditions. The four conditions used to describe a gas—pressure, volume, temperature, and number of moles (quantity)—are all related, along with R, the universal gas law constant, in the following formula:

  PV = nRT

  where P = pressure (atm), V = volume (L), n = number of moles (mol), R = 0.08206 L · atm/mol · K, and T = temperature (K).  Now try an example using the ideal gas law equation.  Example  A 16.0 g sample of methane gas, CH4, the gas used in chemistry lab, has a volume of 5.0 L at 27oC. Calculate the pressure.  Explanation  Looking at all the information given, you have a mass, a volume, and a temperature, and you need to find the pressure of the system. As always, start by checking your units. You must first convert 16.0 g of CH4 into moles: 16.0 g CH41 mol CH4/16.0 g CH4 = 1 mol of methane. The volume is in the correct units, but you must convert the temperature into Kelvins: 27 + 273 = 300K. Now you’re ready to plug these numbers into the ideal gas law equation:

  PV = nRT

  (P) (5.0 L) = (1.0 mol) (0.0821 Latm/molK) (300K), so P = 4.9 atm

  Don't let the math scare you. Remember that your test will be all multiple choice. You may be asked for proper setup, or at least you will have answers to choose from, and you won't have to do these lengthy calculations without a calculator. These examples are only meant to give you practice using the gas law equations.

(责任编辑:申月月)

新东方网托福官方微信:新东方托福 (微信号:xdftoefl

最新考试资讯、托福预测、托福解析,请扫一扫二维码,关注我们的官方微信! 

新东方SAT辅导专区

班级名称 上课地点 上课时间 费用 详细

焦点推荐

精品直播

版权及免责声明

凡本网注明"稿件来源:新东方"的所有文字、图片和音视频稿件,版权均属新东方教育科技集团(含本网和新东方网) 所有,任何媒体、网站或个人未经本网协议授权不得转载、链接、转贴或以其他任何方式复制、发表。已经本网协议授权的媒体、网站,在下载使用时必须注明"稿件来源:新东方",违者本网将依法追究法律责任。

本网未注明"稿件来源:新东方"的文/图等稿件均为转载稿,本网转载仅基于传递更多信息之目的,并不意味着赞同转载稿的观点或证实其内容的真实性。如其他媒体、网站或个人从本网下载使用,必须保留本网注明的"稿件来源",并自负版权等法律责任。如擅自篡改为"稿件来源:新东方",本网将依法追究法律责任。

如本网转载稿涉及版权等问题,请作者见稿后在两周内速来电与新东方网联系,电话:010-60908555。

SAT全科辅导