Concentration expressing in molarity

Using concentrations expressed in molarity and time in seconds, what are the units of the rate constant, k, for (a) a zero-order reaction (b) a first-order reaction (c) a second-order reaction (d) a third-order reaction (e) a half-order reaction ... 

Commercial vinegar contains 5-6% acetic acid. Acetic acid, CH3COOH, is a monoprotic acid. Therefore, its concentration expressed in molarity or normality is the same. It is a weak acid and when titrated with a strong base such as NaOH, upon completion of the titration, there is a sudden change in the pH in the range from 6.0 to 9.0. The best way to monitor such a change is to use the indicator phenolphthalein, which changes from colorless to a pink hue at pH 8.0-9.0. 

Osmotic concentration or osmolarity is the term used to describe the osmotic strength of a solution. It depends only on the ratio of the number of solute particles to the number of solvent particles. Thus the chemical nature and size of the solute are not important, only the concentration, expressed in molarity. For instance, a 2 M solution of glucose (a sugar of molecular weight 180) has the same osmolarity as a 2 M solution of albumin (a protein of molecular weight 60,000). 

Concentration, expressed in molarity, unless otherwise indicated (%)... 

Yc.i, Ym.i, and Yx,i are the activity coefficients related to concentrations expressed in molarities, molalities, and mole fractions, respectively. 

Experiments on sufficiently dilute solutions of non-electrolytes yield Henry s laM>, that the vapour pressure of a volatile solute, i.e. its partial pressure in a gas mixture in equilibrium with the solution, is directly proportional to its concentration, expressed in any units (molar concentrations, molality, mole fraction, weight fraction, etc.) because in sufficiently dilute solution these are all proportional to each other. 

In order to draw the property - composition diagram, coordinates are usually chosen so that the ideal system values correspond with the additive law regarding concentration [313]. It is known, for instance, that in an ideal system, molar volume changes additively with the concentration, and is expressed in molar fractions or molar percentages, whereas specific volume changes linearly with the concentration, and is expressed in mass fractions or mass percentages. 

The logarithm of the micellar molecular weight (M) and consequently the aggregation number of sodium dodecyl sulfate at 25°C in aqueous sodium chloride solutions is linearly related to the logarithm of the CMC plus the concentration of salt (Cs), both expressed in molar units, through two equations [116]. Below 0.45 M NaCl micelles are spherical or globular, and Eq. (18) applies ... 

Liquid phase diffusivities are strongly dependent on the concentration of the diffusing component which is in strong contrast to gas phase diffusivities which are substantially independent of concentration. Values of liquid phase diffusivities which are normally quoted apply to very dilute concentrations of the diffusing component, the only condition under which analytical solutions can be produced for the diffusion equations. For this reason, only dilute solutions are considered here, and in these circumstances no serious error is involved in using Fick s first and second laws expressed in molar units. 

The mode of binding was characterised by replotting experimental data obtained from binding isotherms in terms of the Scatchard representation, [Me +Jb / (Cp.[Me2+]f) vs [Me2+]b/Cp where [Me2+]f corresponds to the final ion concentration at equilibrium. Metal ion concentrations were here expressed in molarity and Cp in number of chain.l l (using the weight-average molecular weights M,). 

A = latm. The units of are (mL gas)/(LSWatm), giving [A(aq)] units of (mL gas)/G. SW). In this concentration unit, the gas abundance is expressed as the volume it would occupy if extracted from the seawater and subjected to STE Under these conditions, the gas s molar volume is 22,414 mL (assuming ideal gas behavior). Thus, gas concentrations expressed in units of can be converted to molarity and molinity (mol/kg) using the following ... 

This equation is the rate law for the decomposition of hydrogen peroxide. The constant k is referred to as the rate constant and the brackets indicate that the concentration of hydrogen peroxide is expressed in molar units. When the concentration is directly proportional to the concentration of a reactant, the reaction is first order with respect to that reactant. Therefore, the decomposition of is first order with respect to H2O2. The reaction order tells us how the reaction rate is related to the concentration. As another example, consider the reaction of hydrogen and iodide to produce hydrogen iodide ... 

Although there are some aspects of micellization that we have not taken into account in this analysis —the fact that n actually has a distribution of values rather than a single value, for example —the above discussion shows that CMC values expressed as mole fractions provide an experimentally accessible way to determine the free energy change accompanying the aggregation of surfactant molecules in water. For computational purposes, remember Equation (3.24), which states that x2 n2/n, for dilute solutions. This means that CMC values expressed in molarity units, [CMC], can be converted to mole fractions by dividing [CMC] by the molar concentration of the solvent, [solvent] x2 [CMC]/[solvent] for water, [solvent] = 55.5 mole liter... 

Substitution of xt by Qt Vt in Eq. 3-40 then yields the partition constant, Kil2, expressed in molar concentrations (note that we now omit the prime superscript) ... 

It should be pointed out that if one of the phases considered is the gas phase, and if K,i2 is expressed in molar concentrations (including the gas phase), AaH, in Eqs. 3-51 and 3-53 has to be replaced by Ai2H + Rff, where Tav is the average temperature (in K) of the temperature range considered (for details see Atkinson and Curthoys, 1978). Finally, we should note that the temperature dependence of Kni (and other equilibrium constants) over large temperature ranges can be approximated by a function of the type ... 

Assuming that the mixture only contains these two components, and if CA and CB are the concentration expressed in mass % of A and B with molar masses of MA and MB, then ... 

A common unit of concentration used by chemists is molarity, which is the solution s concentration expressed in moles of solute per liter of solution ... 

Determining solubility constants in aqueous solutions generally involves analytical work to determine concentrations [ ] or potentiometric measurements to obtain activities. The ratio of activity and concentration—i.e., the activity coefficient and its change with concentration— depends on the choice of the standard state. If pure water is chosen as a standard state, the activity coefficients approach unity only in dilute solutions. It is therefore necessary to express the so-called thermodynamic constants TK (48) in terms of activities. If, on the other hand, one chooses as reference an aqueous solution of comparatively high and constant ionic strength, the activity coefficients remain close to unity even at rather high concentrations of the reacting species. In this case, we may use stoichiometric constants K (48), expressed in molarities, M, and related to a particular ionic medium. 

A solution concentration must be expressed in molality when considering boiling-point elevation or freezing-point depression but can be expressed in molarity when considering osmotic pressure. Why ... 

Enzyme concentration may be expressed in mass unit instead of molar unit. However, the amount of enzyme is not well quantified in mass unit because actual contents of an enzyme can differ widely depending on its purity. Therefore, it is common to express enzyme concentration as an arbitrarily defined unit based on its catalytic ability. For example, one unit of an enzyme, cellobiose, can be defined as the amount of enzyme required to hydrolyze cellobiose to produce 1 /imol of glucose per minute. Whatever unit is adopted for CEq, the unit for k3CEQ should be the same as r, that is, kmole/m3s. Care should be taken for the consistency of unit when enzyme concentration is not expressed in molar unit. 

Besides using the mole fraction scale for concentration, solubility in water can also be expressed in molar concentrations usir%, which can be approximated as the producfeDSnd the molarity... 

Kp can replace K in equation (16-8). If AG° is obtained from a table based on the standard state of 1 atm, Kp will normally be correct only for P in atmospheres. If the values are for a standard state of 1 bar, then Kp will normally apply only to P in bars. When the equation shows no change in the total number of moles of gas as the reaction proceeds (e.g., N2 + O2 == 2NO), Kp will be the same, regardless of the pressure units used and will be identical with the K expressed in molar concentrations. 

The Ka expression is expressed in molar concentrations (denoted by brackets) of the neutral and ionized species involved in the ionization of the acetylsalicylic acid. The pKa (negative log of Ka) of HAsc is 3.2, and at a pH substantially below 3.2, most of this acid is in the neutral HAsc form. This neutral form is easily absorbed by the body, especially in the stomach, where the contents have a low pH of about 1. Many other toxic substances exhibit acid-base behavior and pH is a factor in their uptake. 

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