Search results
Results from the WOW.Com Content Network
Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water.The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution.
FW = Formula weight of the oxidizable compound in the sample, RMO = Ratio of the # of moles of oxygen to # of moles of oxidizable compound in their reaction to CO 2, water, and ammonia. For example, if a sample has 500 Wppm (Weight Parts per Million) of phenol: C 6 H 5 OH + 7O 2 → 6CO 2 + 3H 2 O COD = (500/94)·7·16*2 = 1192 Wppm
1 percent by volume = 10,000 ppmv (i.e., parts per million by volume). Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9.
1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6. Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9 (also referred to as the long scale and short scale billion, respectively).
Chemical shift δ is usually expressed in parts per million (ppm) by frequency, because it is calculated from [5] =, where ν sample is the absolute resonance frequency of the sample, and ν ref is the absolute resonance frequency of a standard reference compound, measured in the same applied magnetic field B 0.
The equation can only be applied when the purged volume of vapor or gas is replaced with "clean" air or gas. For example, the equation can be used to calculate the time required at a certain ventilation rate to reduce a high carbon monoxide concentration in a room.
Bottled mineral water usually contains higher TDS levels than tap water.. Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular (colloidal sol) suspended form.
For example, in order to obtain an accuracy of 1% using a scale with the typical accuracy of 0.2 mg, the sample must contain 20 mg water, which is e.g. 200 mg for a sample with 10% water. For coulometers, the measuring range is from 1–5 ppm to about 5%.