Concentration in parts per million

Eor each of the following, determine the forms of alkalinity (OH , HC03, C03 ) that are present, and their respective concentrations in parts per million. In each case, a 25.00-mL sample is titrated with 0.1198 M HCl to the bromocresol green and phenolphthalein end points. 

The data used are given in Table I. The elimination rate constants included were determined at 20° C. (5). The toxicity to mosquito larvae, given as median lethal dosages (concentration in parts per million of water required to cause 50% mortality in 48 hours), was estimated from the data of Deonier et al. (9) and is probably reproducible to within 30%. 

Miosis Concentration in parts per million (ppm) required to induce significant constriction of the pupil of the eye following a 2-min exposure to the agent. 

Suppose 4.272 g of a soil sample undergoes an extraction with 50 mL of extracting solvent to remove the potassium. This 50 mL is then diluted to 250 mL and tested with an instrument. The concentration of potassium in this diluted extract is found to be 35.7 ppm. What is the potassium concentration, in parts per million, in the untreated soil sample ... 

The total solids concentration in parts per million is designated as C. In most cases, as in Table I, this is inferred from electro-metric determinations of conductivity, which respond only to dissolved solids. Usually, suspended solids are small. 

The minimum mass concentration of oxygen required for fish life is 4 mg-L-1. (a) Assuming the density of lake water to be 1.00 g-mL 1, express this concentration in parts per million by mass, mg-kg L (b) What is the minimum partial pressure of 02 that would supply the minimum mass concentration of oxygen in water in order to support fish life at 20°C (see Table 8.5) (c) What is the minimum atmospheric pressure that would give this partial pressure, assuming that oxygen exerts about 21% of the atmospheric pressure ... 

A hand-held field PID consists of an air uptake pump, an ultraviolet (UV) ionization lamp, a photo multiplier, and a readout device. The air drawn in by the pump passes along the lamp, where organic compounds are ionized with UV light. The resultant current is converted into a signal proportional to the number of ionized molecules. The UV lamp is calibrated with a standard (isobutylene in air), and the readout device provides the vapor concentrations in parts per million-volume (ppm-v). UV lamps are sensitive to the presence of moisture high water vapor content in air will suppress their ionizing action. Some PID models have a moistureabsorbing filter that can be attached to the instrument s inlet. 

Water supplies with dissolved calcium carbonate greater than 500 mg/L are considered unacceptable for most domestic purposes. Express this concentration in parts per million. 

Select a deionization system to treat 250 gal/min (56.8 m3/h) of water at 60°F (289 K) that has the following dissolved components (concentrations in parts per million as CaCC>3 equivalent) calcium, 75 sodium, 50 magnesium, 25 chloride, 30 sulfate, 80 bicarbonate, 40 and silica, 10 (as Si02). Maximum tolerable sodium leakage is 2 ppm silica leakage is to be under 0.05 ppm. Service-cycle length must be at least 12 h. The system is to use sodium hydroxide (available at 120°F) and sulfuric acid for regeneration. 

By means of Table XIII, at the end of this volume, values of concentrations in parts per million may be converted into mgm. per cu. m., and vice versa. 

A sample of 300.0 g of drinking water is found to contain 38 mg Pb. What is this concentration in parts per million ... 

Table 12.7 VOCs Found in the Air of a Sick Building, Their Concentrations in Parts per Million (ppm),[5] and the K Values for These...

The liberated EDTA was titrated with 29.64 mL of 0.05581 M Mg-". Calculate the potassium ion concentration in parts per million. 

The determination in Problem 27-12 was modified to use the standard addition method. As before, a 2.196-g tablet was dissolved in sufficient O.IO M HCl to give 1.000 L. Dilution of a 20.00-mL aliquot to 100 mL gave a solution with a reading of 540 at 347.5 nm. A second 20.00-mL aliquot was mixed with 10.0 mL of 50 ppm quinine solution before dilution to 100 mL. The fluorescence intensity of this solution was 600. Calculate the concentration in parts per million of quinine in the tablet. 

For very dilute solutions, solubility is often expressed in units of parts per million (ppm), which is defined as the quantity of solute dissolved in 1,000,000 equivalent units of solution. As long as the same unit is used for both solute and solvent, the concentration in parts per million is equivalent to the weight, volume, or weight-volume percentages multiplied by 10,000. The descriptive terms of solubility that is expressed in units of parts of solvent required for each part of solute can be found in each edition of the United States Pharmacopeia (Table 1). 

Referring to Table 17.1, calculate the mole fraction of CO2 and its concentration in parts per million by volume. 

Fio. 2. The concentrations of silver, lead, and copper in sediments of the Quinniptac River (Connecticut) system (previously unpublished Yale University data). Analyses made by emission spectrography. Concentrations in parts per million. 

What does 1 ppm represent in terms of moles per liter It depends on the formula weight, but the approximate relationship between concentrations in parts per million (or parts per billion) and in moles per liter can be seen by assuming a formula weight of 100 for an analyte. Then, since 1 ppm = 10 g/L, it is equal to (10 g/L) (10 g/mol) = 10 mol/L. Similarly, 1 ppb = 10 mol/L. Note that this latter concentration is smaller than the hydrogen ion concentration in pure water (10" mol/L) Of course, this relationship is approximate and will vary with the formula weight. One part per million solutions of zinc and copper, for example, will not be the same molarity. Conversely, equal molar solutions of different species will not be equal in terms of ppm unless the formula weights are equal. The former concentration is based on the number of molecules per unit volume, while the latter is based on the weight of the species per unit volume. 

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