溶液濃度的各單位換算方法及其定義

溶液濃度的各種單位之間的換算方法及其各自定義。

濃度及濃度單位換算

（一）、溶液的濃度
溶液濃度可分為:
品質濃度（如品質百分濃度）
體積濃度（如摩爾濃度、當量濃度）
體積濃度

1、品質百分濃度
溶液的濃度用溶質的品質佔全部溶液品質的百分率表示的叫品質百分濃度，用符號%表示。例如:
50%的葡萄糖注射液就是指100g注射液中含葡萄糖25g。

品質百分濃度（%）=溶質品質/溶液品質x100%

2、體積濃度
（1）、摩爾濃度
溶液的濃度用1升溶液中所含溶質的摩爾數來表示的叫摩爾濃度，用符號mol表示， 例如:
1升濃硫酸中含18.4
摩爾的硫酸，則濃度為18.4mol。
摩爾濃度（mol）=溶質摩爾數/溶液體積（升）

（2）、當量濃度(N)
這個東西現在基本不用了，淘汰單位，但是在50年代那會的書裏面還是很多的。溶液的濃度用1升溶液中所含溶質的克當量數來表示的叫當量濃度，用符號N表示。 例如:
1升濃鹽酸中含12.0克當量的鹽酸(HCl)，則濃度為12.0N。
當量濃度=溶質的克當量數/溶液體積（升）

3、品質-體積濃度
用單位體積（1立方米或1升）溶液中所含的溶質質量數來表示的濃度叫質量-體積濃度，以符號g/m3或mg/L表示。例如:
1升含鉻廢水中含六價鉻品質為2毫克，則六價鉻的濃度為2毫克/升（mg/L）
品質-體積濃度=溶質的質量數（克或毫克）/溶液的體積（立方米或升）

4、濃度單位的換算公式：
l 當量濃度=1000.d.品質百分濃度/E
l 品質百分濃度=當量濃度E/1000.d
l 摩爾濃度=1000.d品質百分濃度/M
l 品質百分濃度=品質-體積濃度（毫克/升）/104.d
l 品質-體積濃度（mg/L）=104品質百分濃度
l ppm是重量的百分率，ppm=mg/kg=mg/L

即:1ppm=1ppm=1000ug/L
1ppb=1ug/L=0.001mg
式中：E—溶質的克當量；
d—溶液的比重；
M—溶質的摩爾品質；

（二）、氣體濃度
對大氣中的污染物，常見體積濃度和品質-體積濃度來表示其在大氣中的含量。
1、體積濃度
體積濃度是用每立方米的大氣中含有污染物的體積數（立方釐米）或（ml/m3）來表示，
常用的表示方法是ppm，即1ppm=1立方釐米/立方米=10-6。除ppm外，還有ppb和ppt，

他們之間的關係是：
1ppm=10-6=一百萬分之一， 1ppb=10-9=十億分之一 ，
1ppt=10-12=萬億分之一， 1ppm=103ppb=106ppt

2、品質-體積濃度
用每立方米大氣中污染物的質量數來表示的濃度叫品質-體積濃度，單位是毫克/立方米或克/立方米。

它與ppm的換算關係是：
X=M.C/22.4
C=22.4X/M
式中： X—污染物以每標立方米的毫克數表示的濃度值；
C—污染物以ppm表示的濃度值；
M—污染物的分之子量。
由上式可得到如下關係：

1ppm=M/22.4(mg/m3）=1000.m/22.4ug/m3
例1：求在標準狀態下，30毫克/標立方米的氟化氫的ppm濃度。
解：氟化氫的分子量為20，則：
C=30.22.4/20=33.6ppm

例2、已知大氣中二氧化硫的濃度為5ppm，求以mg/Nm3表示的濃度值。
解：二氧化硫的分子量為64。
X =5.64/22.4mg/m3=14.3mg/m3

3、在土壤、動植物、固體廢棄物中ppm、ppb與品質含量換算：
1ppm=1mg/kg=1000ug/kg
1ppb=1ug/kg=10-3mg/kg
1mg/kg=1ppm=1000ug/kg
1ug/kg=1ppb=10-3ppm

What is Analytical Chemistry?

Analytical Chemistry seeks ever improved means of measuring the chemical composition of natural and artificial materials. The techniques of this science are used to identify the substances which may be present in a material and to determine the exact amounts of the identified substances. Analytical chemists work to improve the reliability of existing techniques to meet the demands for better chemical measurements which arise constantly in our society. They adapt proven methodologies to new kinds of materials or to answer new questions about their composition. They carry out research to discover completely new principles of measurement and are at the forefront of the utilization of major discoveries such as lasers and microchip devices for practical purposes. They make important contributions to many other fields as diverse as forensic chemistry, archaeology, and space science. As the emblem above points out, analytical chemistry serves the needs of many fields.
In medicine, analytical chemistry is the basis for clinical laboratory tests which help physicians diagnose disease and chart progress in recovery.
In industry, analytical chemistry provides the means of testing raw materials and for assuring the quality of finished products whose chemical composition is critical. Many household products, fuels, paints, pharmaceuticals, etc. are analyzed by the procedures developed by analytical chemists before being sold to the consumer.
Environmental quality is often evaluated by testing for suspected contaminants using the techniques of analytical chemistry.
The nutritional value of food is determined by chemical analysis for major components such as protein and carbohydrates and trace components such as vitamins and minerals. Indeed even the calories in a food are often calculated from its chemical analysis.
Analytical chemists also make important contributions to fields as diverse as forensic chemistry, archaeology, and space science.
form: http://www.acs-analytical.duq.edu/whatisanalyticalchem.html