# Concentration: Wikis

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# Encyclopedia

.In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance.^ This potential difference cannot be measured because there is no way to make an electrical connection to the solution phase without setting up another electrode potential.

^ The quantitative and characteristic measure of the conductivity of a given substance.

.This can apply to any sort of chemical mixture, but most frequently the concept is limited to homogeneous solutions, where it refers to the amount of solute in the solvent.^ A homogeneous mixture of a liquid (the solvent ) with a gas or solid (the solute ).

.To concentrate a solution, one must add more solute (e.g.^ Strictly speaking, one must use unit activity rather than concentration of hydrogen ions and unit fugacity rather than unit pressure of hydrogen gas.

^ This is because in the calculation of the solubility product one must use the "total" chloride concentration in the solution, therefore a silver concentration lower than in water is needed to satisfy a constant solubility product.

alcohol), or reduce the amount of solvent (e.g. water). .By contrast, to dilute a solution, one must add more solvent, or reduce the amount of solute.^ One containing more than the equilibrium amount is supersaturated .

.Unless two substances are fully miscible there exists a concentration at which no further solute will dissolve in a solution.^ If the solution contained all ions and no particles, it would be considered an ionic solution, not a colloid since there would be no particles suspended in the water.

^ In a saturated solution the dissolved substance is in equilibrium with the undissolved substance; i.e.

^ Further, if there is a conflict in the U.S. involving only the U.S. this convention or treaty can go into operation; which includes the procedures for setting up the concentration camps.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

At this point, the solution is said to be saturated. .If additional solute is added to a saturated solution, it will not dissolve (except in certain circumstances, when supersaturation may occur).^ Supersaturated solutions can be made by slowly cooling a saturated solution.

^ A solution is called "saturated" if it contains the maximum dissolvable amount.

^ The process that may occur when a chemical compound is dissolved in a solvent (e.g., water).

Instead, phase separation will occur, leading to either coexisting phases or a suspension. .The point of saturation depends on many variables such as ambient temperature and the precise chemical nature of the solvent and solute.^ The speed of movement is dependent on the size of the particle, as well as temperature and other variables such as viscosity.

^ When the water is evaporated the solids that remain consist of silver compounds such as silver carbonate and silver hydroxide depending on what anions where in solution with the silver.

.Analytical concentration includes all the forms of that substance in the solution.^ A liquid that dissolves another substance or substances to form a solution .

## Qualitative description

These glasses containing red dye demonstrate qualitative changes in concentration. The solutions on the left are more dilute, compared to the more concentrated solutions on the right.
.Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as "dilute" for solutions of relatively low concentration and of others like "concentrated" for solutions of relatively high concentration.^ Through the use of t-valves, concentration camps become unnecessary.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

Those terms relate the amount of a substance in a mixture to the observable intensity of effects or properties caused by that substance. .For example, a practical rule is that the more concentrated a chromatic solution is, the more intensely colored it is (usually).^ Law is usually practiced by the "buddy system", hence the court rules are overlooked or not followed.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

## Quantitative notation

For scientific or technical applications, a qualitative account of concentration is almost never sufficient; therefore quantitative measures are needed to describe concentration. There are a number of different ways to quantitatively express concentration; the most common are listed below. .They are based on mass, volume, or both.^ The base has signs in both English and the Iraqi language, as they have brought so many from that country.
• Concentration Camp Locations 10 February 2010 13:40 UTC www.greatdreams.com [Source type: FILTERED WITH BAYES]

Depending on what they are based on it is not always trivial to convert one measure to the other, because knowledge of the density might be needed to do so. At times this information may not be available, particularly if the temperature varies.

### Mass versus volume

Units of concentration — particularly the most popular one, molarity — require knowledge of a substance's volume, which unlike mass is variable depending on ambient temperature and pressure. In fact (partial) molar volume can even be a function of concentration itself. This is why volumes are not necessarily completely additive when two liquids are added and mixed. Volume-based measures for concentration are therefore not to be recommended for non-dilute solutions or problems where relatively large differences in temperature are encountered (e.g. for phase diagrams).
Unless otherwise stated, all the following measurements of volume are assumed to be at a standard state temperature and pressure (for example 0 degrees Celsius at 1 atmosphere or 101.325 kPa). The measurement of mass does not require such restrictions.
Mass can be determined at a precision of < 0.2 mg on a routine basis with an analytical balance and more precise instruments exist. Both solids and liquids are easily quantified by weighing.
The volume of a liquid is usually determined by calibrated glassware such as burettes and volumetric flasks. For very small volumes precision syringes are available. .The use of graduated beakers and cylinders is not recommended as their indication of volume is mostly for decorative rather than quantitative purposes.^ If you wish to use this material for purposes other than provided by law.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

The volume of solids, particularly of powders, is often difficult to measure, which is why mass is the more usual measure. For gases the opposite is true: the volume of a gas can be measured in a gas burette, if care is taken to control the pressure, but the mass is not easy to measure due to buoyancy effects.

### Molarity

Molarity (in units of mol/L, molar, or M) or molar concentration denotes the number of moles of a given substance per liter of solution. A capital letter M is used to abbreviate units of mol/L. For instance:
$\frac{2.0 ext{ moles of dissolved particles}}{4.0 ext{ liters of liquid}} = ext{ solution of 0.5 mol/L}.$
The actual formula for molarity is:
$\frac{ ext{ Moles of solute}}{ ext{ Liters of solution}} = ext{ Molarity of solution}.$
Such a solution may be described as "0.50 molar." It must be emphasized a 0.5 molar solution contains 0.5 moles of solute in 1.0 liter of solution. This is not equivalent to 1.0 liter of solvent. A 0.5 mol/L solution will contain either slightly more or slightly less than 1 liter of solvent because the process of dissolution causes volume of liquid to increase or decrease.
.Following the SI system of units, the National Institute of Standards and Technology, the United States authority on measurement, considers the term molarity and the unit symbol M to be obsolete, and suggests instead the amount-of-substance concentration (c) with the units mol/m3 or other units used alongside the SI such as mol/L[1].^ He will command U.S. forces that operate within the United States in support of civil authorities.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

^ Other far-flung delusions may involve the United Nations, "black helicopters," concentration camps, or the Council on Foreign Relations (CFR).
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

^ This is because the L.E.A.A. is not geared to fighting crime; it's geared to developing a system for takeover of the United States with the assistance of the Department of Defense.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

This recommendation has not been universally implemented in academia or chemistry research yet.
Preparation of a solution of known molarity involves adding an accurately weighed amount of solute to a volumetric flask, adding some solvent to dissolve it, then adding more solvent to fill to the volume mark.
When discussing molarity of minute concentrations, such as in pharmacological research, molarity is expressed in units of millimolar (mmol/L, mM, 1 thousandth of a molar), micromolar (μmol/L, μM, 1 millionth of a molar) or nanomolar (nmol/L, nM, 1 billionth of a molar).
Although molarity is by far the most commonly used measure of concentration, particularly for dilute aqueous solutions, it does suffer from a number of disadvantages. Masses can be determined with great precision as balances are often very precise. Determining volume is often not as precise. In addition, due to a thermal expansion, molarity of a solution changes with temperature without adding or removing any mass.[2] For non-dilute solutions another problem is the molar volume of a substance is itself a function of concentration so volume is not strictly additive.

### Molality

Molality (mol/kg, molal, or m) denotes the number of moles of solute per kilogram of solvent (not solution). For instance: adding 1.0 mole of solute to 2.0 kilograms of solvent constitutes a solution with a molality of 0.50 mol/kg. Such a solution may be described as "0.50 molal". The term molal solution is used as a shorthand for a "one molal solution", i.e. a solution which contains one mole of the solute per 1000 grams of the solvent.
Following the SI system of units, the National Institute of Standards and Technology, the United States authority on measurement, considers the unit symbol m to be obsolete, and suggests instead the term 'molality of substance B' (mB) with units mol/kg or a related unit of the SI[3]. This recommendation has not been universally implemented in academia yet.
Note: molality is sometimes represented by the symbol (m), while molarity by the symbol (M). The two symbols are not meant to be confused, and should not be used as symbols for units. The SI unit for molality is mol/kg. (The unit m means meter.)
Like other mass-based measures, the determination of molality only requires a good scale, because masses of both solvent and solute can be obtained by weighing, and molality is independent of physical conditions like temperature and pressure, providing advantages over molarity.
In a dilute aqueous solution near room temperature and standard atmospheric pressure, molarity and molality will be very similar in value. This is because 1 kg of water roughly corresponds to a volume of 1 L at these conditions, and because the solution is dilute, the addition of the solute makes a negligible impact on the volume of the solution.
However, in all other conditions, this is usually not the case.

### Mole fraction

The mole fraction Χ, (also called molar fraction) denotes the number of moles of solute as a proportion of the total number of moles in a solution. For instance: 1 mole of solute dissolved in 9 moles of solvent has a mole fraction of 1/10 or 0.1. Mole fractions are dimensionless quantities. (The mole percentage or molar percentage, denoted "mol %" and equal to 100% times the mole fraction, is sometimes quoted instead of the mole fraction.)
This measure is used very frequently in the construction of phase diagrams. It has a number of advantages:
• the measure is not temperature dependent (such as molarity) and does not require knowledge of the densities of the phase(s) involved
• a mixture of known mole fraction can be prepared by weighing off the appropriate masses of the constituents
• the measure is symmetrical: in the mole fractions Χ=0.1 and Χ=0.9, the roles of 'solvent' and 'solute' are reversed.
As both mole fractions and molality are only based on the masses of the components it is easy to convert between these measures. This is not true for molarity, which requires knowledge of the density.

### Mass percentage (fraction)

Mass percentage denotes the mass of a substance in a mixture as a percentage of the mass of the entire mixture. (Mass fraction xm can be used instead of mass percentage by dividing mass percentage to 100.) Commercial concentrated aqueous reagents such as acids and bases are often labeled in concentrations of weight percentage with the specific gravity also listed. In older texts and references this is sometimes referred to as weight-weight percentage (abbreviated as w/w% [4] or wt%). In water pollution chemistry, a common term of measuring total mass percentage of dissolved solids in an aqueous medium is total dissolved solids.
For instance: if a bottle contains 40 grams of ethanol and 60 grams of water, then it contains 40% ethanol by mass or 0.4 mass fraction ethanol. Note that the total weight of the solution will be 100 grams, but the total volume of the solution will be more than 100 milliliters because ethanol is less dense than water. *In the case of ethanol and water resulting volume will be less than the sum of the two initial volumes*

### Mass-volume percentage

Mass-volume percentage, (sometimes referred to as weight-volume percentage or percent weight per volume and often abbreviated as % m/v or % w/v) describes the mass of the solute in g per 100 mL of the resulting solution. Mass-volume percentage is often used for solutions made from a solid solute dissolved in a liquid. For example, a 40% w/v sugar solution contains 40 g of sugar per 100 mL of resulting solution.

### Volume-volume percentage

Volume-volume percentage (sometimes referred to as percent volume per volume and abbreviated as % v/v) describes the volume of the solute in mL per 100 mL of the resulting solution. This is most useful when a liquid - liquid solution is being prepared, although it is used for mixtures of gases as well. For example, a 40% v/v ethanol solution contains 40 mL ethanol per 100 mL total volume. The percentages are only additive in the case of mixtures of ideal gases.

### Normality

Normality highlights the chemical nature of salts: in solution, salts dissociate into distinct reactive species (ions such as H+, Fe3+, or Cl-). Normality accounts for any discrepancy between the concentrations of the various ionic species in a solution. For example, in a salt such as MgCl2, there are two moles of Cl- for every mole of Mg2+, so the concentration of Cl- is said to be 2 N (read: "two normal"). Further examples are given below. It may also refer to the concentration of a solute in any solution. The normality of a solution is the number of gram equivalent weight of a solute per liter of its solution. The definition of normality depends on the exact reaction intended.
For example, hydrochloric acid (HCl) is a monoprotic acid and thus has 1 mol = 1 gram equivalent. One liter of aqueous solution of HCl acid contains 36.5 grams HCl. It is called 1 N (one normal) solution of HCl. It is given by the following formula:
$\mbox{normality, } N =\left ( \frac{\mathrm{gram\ equivalents}}{\mathrm{liters\ solution}} \right )$
In contrast, for sulfuric acid, which is diprotic acid, 2 N is usually 1 M, but may be defined as 2 M if pH < 2, where the once-deprotonated species, hydrogen sulfate, does not deprotonate.

#### Definition

A normal is one gram equivalent of a solute per liter of solution. The definition of a gram equivalent varies depending on the type of chemical reaction that is discussed — it can refer to acids, bases, redox species, and ions that will precipitate.

#### Usage

It is critical to note that normality measures a single ion which takes part in an overall solute. For example, one could determine the normality of hydroxide or sodium in an aqueous solution of sodium hydroxide, but the normality of sodium hydroxide itself has no meaning. Nevertheless it is often used to describe solutions of acids or bases, in those cases it is implied that the normality refers to the H+ or OH ion. For example, 2 Normal sulfuric acid (H2SO4), means that the normality of H+ ions is 2, or that the molarity of the sulfuric acid is 1. Similarly for 1 molar H3PO4 the normality is 3 as it contains three moles of H+ ions for every mole of PO43- .

#### Specific cases

As ions in solution can react through different pathways, there are three common definitions for normality as a measure of reactive species in solution:
• In acid-base chemistry, normality is used to express the concentration of protons or hydroxide ions in the solution. Here, the normality differs from the molarity by an integer value - each solute can produce n equivalents of reactive species when dissolved. For example: 1 M aqueous Ca(OH)2 is 2 N (normal) in hydroxide.
• In redox reactions, normality measures the quantity of oxidizing or reducing agent that can accept or furnish one mole of electrons. Here, the normality scales from the molarity, most commonly, by a fractional value. Calculating the normality of redox species in solution can be challenging.
• In precipitation reactions, normality measures the concentration of ions which will precipitate in a given reaction. Here, the normality scales from the molarity again by an integer value.

#### Practical uses

The measure of normality is extremely useful for titrations — given two species that are known to react with a known ratio, one simply needs to scale the volumes of solutions with known normalities to get a complete reaction with the following equation:
NaVa=NbVb
However, normality cannot reliably represent an unambiguous measure of the concentration of a solution. Since the measure of normality depends on the reaction that the solute participates in, the same concentration of solute can possess two different normalities for two different reactions. For example, Mg2+ is 2 N with respect to a Cl- ion, but it is only 1 N with respect to an O2- ion.
Accordingly, normality is no longer used to represent the concentration of a solution as such. Instead, a solution should be labeled according to its molarity, and it is then possible to calculate the normality for a particular titration using the equation above. NIST has also stipulated that this unit is obsolete and recommends discontinuing its use.

### Equivalents

Expression of concentration in equivalents per liter (or more commonly, milliequivalents per liter) is based on the same principle as normality. A normal solution is one equivalent per liter of solution (Eq/L). The use of equivalents and milliequivalents as a means of expressing concentration is losing favor, but medical reporting of serum concentrations in mEq/L still occurs.

### Formal

The formal (F) is yet another measure of concentration similar to molarity. Formal concentrations are sometimes used when solving chemical equilibrium problems. It is calculated based on the formula weights of chemicals per liter of solution. .The difference between formal and molar concentrations is that the formal concentration indicates moles of the original chemical formula in solution, without regard for the species that actually exist in solution.^ CONCENTRATION CAMPS IN THE US. DON'T BE IN DENIAL - THEY EXIST IMPOSSIBLE TO NUDGE EARTH INTO DIFFERENT ORBIT!!!!
• Concentration Camp Locations 10 February 2010 13:40 UTC www.greatdreams.com [Source type: FILTERED WITH BAYES]

^ CONCENTRATION CAMPS IN THE US. DON'T BE IN DENIAL - THEY EXIST IMPOSSIBLE TO NUDGE EARTH INTO DIFFERENT ORBIT! ...
• Concentration Camp Locations 10 February 2010 13:40 UTC www.greatdreams.com [Source type: FILTERED WITH BAYES]

Molar concentration, on the other hand, is the concentration of species in solution.
For example: if one dissolves sodium carbonate (Na2CO3) in a liter of water, the compound dissociates into the Na+ and CO32- ions. Some of the CO32- reacts with the water to form HCO3- and H2CO3. If the pH of the solution is low, there is practically no Na2CO3 left in the solution. So, although we have added 1 mol of Na2CO3 to the solution, it does not contain 1 M of that substance. (Rather, it contains a molarity based on the other constituents of the solution.) However, it was once said that such solutions contain 1 F of Na2CO3.

### "Parts-per" notation

The parts-per notation is used in some areas of science and engineering because it does not require conversion from weights or volumes to more chemically relevant units such as normality or molarity. It describes the amount of one substance in another, and is thus related to the mass fraction. It is the ratio of the amount of the substance of interest to the amount of that substance plus the amount of the substance it is in.
• Parts per hundred (denoted by '%' [the per cent symbol], and very rarely 'pph') - denotes the amount of a given substance in a total amount of 100 regardless of the units of measure as long as they are the same. e.g. 1 gram per 100 gram. 1 part in 102.
• Parts per thousand (denoted by '‰' [the per mille symbol], and occasionally 'ppt', but this usage can be confusing because it more often denotes parts per trillion) denotes the amount of a given substance in a total amount of 1000 regardless of the units of measure as long as they are the same. e.g. 1 milligram per gram, or 1 gram per kilogram. 1 part in 103.
• Parts per million ('ppm') denotes the amount of a given substance in a total amount of 1,000,000 regardless of the units of measure used as long as they are the same. e.g. 1 milligram per kilogram. 1 part in 106.
• Parts per billion ('ppb') denotes the amount of a given substance in a total amount of 1,000,000,000 regardless of the units of measure as long as they are the same. e.g. 1 milligram per tonne. 1 part in 109.
• Parts per trillion ('ppt') denotes the amount of a given substance in a total amount of 1,000,000,000,000 regardless of the units of measure as long as they are the same. e.g. 1 milligram per kilotonne. 1 part in 1012.
• Parts per quadrillion ('ppq') denotes the amount of a given substance in a total amount of 1,000,000,000,000,000 regardless of the units of measure as long as they are the same. e.g. 1 milligram per megatonne. 1 part in 1015.

#### Notes for clarity

The notation is used for convenience and the units of measure must be denoted for clarity though this is frequently not the case even in technical publications.
In atmospheric chemistry and in air pollution regulations, the parts per notation is commonly expressed with a v following, such as ppmv, to indicate parts per million by volume. This works fine for gas concentrations (e.g., ppmv of carbon dioxide in the ambient air) but, for concentrations of non-gaseous substances such as aerosols, cloud droplets, and particulate matter in the ambient air, the concentrations are commonly expressed as μg/m3 or mg/m3 (e.g., μg or mg of particulates per cubic metre of ambient air). This expression eliminates the need to take into account the impact of temperature and pressure on the density and hence weight of the gas.
The usage is generally quite fixed inside most specific branches of science, leading some researchers to believe that their own usage (mass/mass, volume/volume or others) is the only correct one. This, in turn, leads them not to specify their usage in their research, and others may therefore misinterpret their results. For example, electrochemists often use volume/volume, while chemical engineers may use mass/mass as well as volume/volume. Many academic papers of otherwise excellent level fail to specify their usage of the part-per notation. The difference between expressing concentrations as mass/mass or volume/volume is quite significant when dealing with gases and it is very important to specify which is being used. It is quite simple, for example, to distinguish ppm by volume from ppm by mass or weight by using ppmv or ppmw.

## Table of concentration measures

Frequently used standards of concentration
Measurement Notation Generic formula Typical units
atomic percentage (A) at.% $\left ( \frac{\rm number~of~atoms~of~dopant imes 100}{\rm number~of~atoms~of~solution} \right )$ %
atomic percentage (B) at.% $\left ( \frac{\rm number~of~atoms~of~dopant imes 100}{\rm number~of~substitutable~atoms~of~solution} \right )$ %
Mass percentage wt% $\left ( \frac{\mathrm{grams\ solute} imes 100}{\mathrm{grams\ solution}} \right )$ %
Mass-volume percentage - $\left ( \frac{\mathrm{grams\ solute} imes 100}{\mathrm{milliliters\ solution}} \right )$ % though strictly %g/mL
Volume-volume percentage vol% $\left ( \frac{\mathrm{milliliters\ solute} imes 100}{\mathrm{milliliters\ solution}} \right )$ %
Molarity M $\left ( \frac{\mathrm{moles\ solute}}{\mathrm{liters\ solution}} \right )$ mol/L (or M or mol/dm3)
Molinity - $\left ( \frac{\mathrm{moles\ solute}}{\mathrm{kilograms\ solution}} \right )$ mol/kg
Molality m $\left ( \frac{\mathrm{moles\ solute}}{\mathrm{kilograms\ solvent}} \right )$ mol/kg (or m**)
Molar fraction χ (chi) $\left ( \frac{\mathrm{moles\ solute}}{\mathrm{moles\ solution}} \right )$ (decimal)
Formal F $\left ( \frac{\mathrm{moles\ undissolved\ solute}}{\mathrm{liters\ solution}} \right )$ mol/L (or F)
Normality N $\left ( \frac{\mathrm{gram\ equivalents}}{\mathrm{liters\ solution}} \right )$ N
Parts per hundred % (or pph) $\left ( \frac{\mathrm{dekagrams\ solute}}{\mathrm{kilograms\ solution}} \right )$ dg/kg
Parts per thousand ‰ (or ppt*) $\left ( \frac{\mathrm{grams\ solute}}{\mathrm{kilograms\ solution}} \right )$ g/kg
Parts per million ppm $\left ( \frac{\mathrm{milligrams\ solute}}{\mathrm{kilograms\ solution}} \right )$ mg/kg
Parts per billion ppb $\left ( \frac{\mathrm{micrograms\ solute}}{\mathrm{kilograms\ solution}} \right )$ µg/kg
Parts per trillion ppt* $\left ( \frac{\mathrm{nanograms\ solute}}{\mathrm{kilograms\ solution}} \right )$ ng/kg
Parts per quadrillion ppq $\left ( \frac{\mathrm{picograms\ solute}}{\mathrm{kilograms\ solution}} \right )$ pg/kg
* Although 'ppt' is usually used to denote 'parts per trillion', it is on occasion used for 'parts per thousand'. Sometimes 'ppt' is also used as an abbreviation for precipitate.
** Obsolete unit symbols.

## References

1. ^ "NIST Guide to SI Units". Retrieved 2007-09-03.
2. ^ Myron Kaufman (2002), Principles of thermodynamics, CRC Press, p. 213, ISBN 0-8247-0692-7
3. ^ "NIST Guide to SI Units". Retrieved 2007-12-17.
4. ^ Prof. N. De Leon. [xxx "Concentration: Weight/Weight %"] (HTML). C101 Class Notes. Indiana University Northwest. xxx. Retrieved 2009-11-07.
• Note (1) : The table above is described in terms of solvents and solutes; however the units given often also apply to other types of mixture.
• Note (2) : The use of billion, trillion, and quadrillion above follows the short scale usage of these words.

# Source material

Up to date as of January 22, 2010

### From Wikisource

 Hermione and Her Little Group of Serious Thinkers by Don Marquis Concentration
[]
CONCENTRATION
.
ISN'T it just simply terrible the way the Balkans are bombarding Venice… all those beautiful Doges and things, you know.
^ We all know those people in life who succeed.
• Drive Focus and Concentration Hypnosis MP3 Download 10 February 2010 13:40 UTC www.hypnosisdirect.com [Source type: General]

• How To Improve Your Concentration Skills? | Self Help Zone 10 February 2010 13:40 UTC www.selfhelpzone.com [Source type: General]

^ It can help to set them just before something that you know you will do, to ensure that you stop worrying on time - e.g.
• Cambridge University Counselling Service: Self-help leaflets: Concentration 10 February 2010 13:40 UTC www.counselling.cam.ac.uk [Source type: General]
• Concentration 10 February 2010 13:40 UTC www.ucl.ac.uk [Source type: General]

.I suppose there will be nothing left, just simply nothing, of the city that Byron wrote about in—in—what was it?^ It's shocking how little there is to do with tennis when you're just thinking about nothing except winning every point .
• Concentration at Bridge 10 February 2010 13:40 UTC www.bridgeguys.com [Source type: Original source]

^ If you read the Order, there is nothing at all left to the imagination.
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

^ Many go about looking, searching for something worthwhile, something wonderful, but there is nothing more wonderful than the soul of man.
• VOLUME IV - 26 10 February 2010 13:40 UTC wahiduddin.net [Source type: Original source]

Oh, yes, in "Childe Harold to the Dark Tower Came."
.That's one comforting thing to think of if this country ever gets into war, isn't it?—I mean that we haven't any of those lovely old things that can be bombarded, you know.^ You probably haven't done any of those.
• Improving Your Concentration 10 February 2010 13:40 UTC www.k-state.edu [Source type: General]

^ Short relaxations to help you feel and think clearer and live life more comfortably.
• concentration podcast 10 February 2010 13:40 UTC www.podbean.com [Source type: General]

^ We always love to hear how we’re doing – let us know your thoughts as you keep exploring.
• How can I improve concentration and memory? | SharpBrains 10 February 2010 13:40 UTC www.sharpbrains.com [Source type: General]

.I suppose if we ever did get into war someone like Edison would invent something quick, you know, and it would be all over in a few hours.^ Would you like to comment?
• Concentration. on Flickr - Photo Sharing! 10 February 2010 13:40 UTC www.flickr.com [Source type: FILTERED WITH BAYES]

^ Seeing yourself as you would like to be.

^ Where would you like to go now?
• The effect of concentration on rates of reaction 10 February 2010 13:40 UTC www.chemguide.co.uk [Source type: FILTERED WITH BAYES]

Isn't inventive science wonderful! Just simply wonderful!
.It's so—so—well, so dynamic, if you get what I mean.^ This means how well you are able to filter information and events as they come at you.
• Improve Focus and Concentration How To ConcentrateBetter Exercises 10 February 2010 13:40 UTC www.iqmindbrainlibrary.com [Source type: General]

Isn't it?
.Don't you just dote on dynamic things?^ Don't just say you are going to "study chemistry," set definite plan: "I will read ten pages and answer five questions."
• Utah State University 10 February 2010 13:40 UTC www.usu.edu [Source type: General]

^ If you want to learn or remember something, concentrate on just that one thing.
• How can I improve concentration and memory? | SharpBrains 10 February 2010 13:40 UTC www.sharpbrains.com [Source type: General]

^ Apply The 5 More Rule Instead of just quitting the task all together, you tell yourself to do  only 5 more things before you quit.

Dynamic personalities, especially.
.I've often thought if I had it to do over again I'd go in less for psychics and more for dynamics.^ While a molecule is often thought of as consisting of more than one atom , this is not always true.
• Chemistry & Environmental Dictionary: Molality - MWC (EnvironmentalChemistry.com) 11 September 2009 8:43 UTC environmentalchemistry.com [Source type: FILTERED WITH BAYES]

.[]But then there are so many things that a modern thinker must keep up with, aren't there?^ As you keep on meditating without let-up, things keep growing more refined step by step.

^ Many of the Jews of this photograph will end up there after the quick selection to be killed.
• Auschwitz-Birkenau Concentration Camp Complex --data and summary facts 10 February 2010 13:40 UTC isurvived.org [Source type: FILTERED WITH BAYES]

^ We each have many distractions that keep us from getting things done.
• Concentration - Stepcase Lifehack 10 February 2010 13:40 UTC www.lifehack.org [Source type: General]

.And it's easy enough to concentrate one's mind on one or two things, but I often find it terribly difficult to concentrate on ten or twelve different things all at the same time.^ Concentrate to find them all!
• Concentration Games | Memory Games | Match Games for Kids 10 February 2010 13:40 UTC www.apples4theteacher.com [Source type: General]

^ This is concentration or one-pointedness of mind.

^ One-Pointedness Concentration means that we can focus on one thing, to the exclusion of all else.
• Concentration - Stepcase Lifehack 10 February 2010 13:40 UTC www.lifehack.org [Source type: General]

.And one must if one is to keep up with the very latest in Thought and Life.^ You can break up old thought-habits and build up new ones by sheer force of Will.

^ I'm using the Thought Stopping technique at the inception of any possible illness or adversity and it opens up SUCH SPACE. Thank you very much.

^ You must change your Thought-Habits and shift your plane of consciousness from the lower to the higher life.

Concentration! Concentration! That is the key to it all! .Nearly every night when I am alone with my own Ego I go into the Silences for a little period of Spiritual Self-Examination and I always ask myself: "Have I Concentrated today?^ Asked whether he'd like to work on an acting project with his daughter, he said: "Maybe in the distant future, yes, but I think at she moment she's going to concentrate on school.
• Concentrate | Metro.co.uk 15 September 2009 7:07 UTC search.metro.co.uk [Source type: General]

^ Concentrate at will and examine in depth any given topic, even in extremely distracting situations for extended periods of time and with less effort .

^ But, you'll find that the period of time between your straying thoughts gets a little longer every few days.
• Improving Your Concentration 10 February 2010 13:40 UTC www.k-state.edu [Source type: General]

Really Concentrated? Or have I failed?"
.I call these little times my Psychic Inquisitions.^ I need really good advice on how to improve my memory so i can learn more in little time possible and most importantly improve concentration .
• improve concentration 10 February 2010 13:40 UTC getsynergized.com [Source type: General]

^ In my marriage, I get called out on it all the time .
• Amazing Powers of Concentration 10 February 2010 13:40 UTC www.feld.com [Source type: General]

.In the hurry of this crowded age one must find time to get alone with one's self, must one not?^ Again, with a little mental self-discipline at the beginning of meditation, one finds it increasingly easy to remain without thought.
• The Meditation Doctor: Lack of Concentration- Concentration Is Everything 10 February 2010 13:40 UTC www.meditationdoctor.org [Source type: Original source]
• Concentration is Everything 10 February 2010 13:40 UTC www.ananda.org [Source type: General]

^ A time will come when the mind will stick to one point alone.

Fothy Finch has written a beautiful thing about the hurry of this crowded age which I wish everyone could hang over his desk.
Well, I must be going on now. I have a committee meeting for this afternoon. I can't for the life of me remember whether it's about suffrage—Oh, yes, I marched!—or about some relief fund.

# Gaming

Up to date as of February 01, 2010

### From Wikia Gaming, your source for walkthroughs, games, guides, and more!

 A Game Of Concentration Developer(s) Atari Publisher(s) Atari Release date Genre Edutainment Mode(s) Single player 1-2 players Age rating(s) N/A Atari 2600 Platform(s) Atari 2600 Input Atari 2600 Keyboard Controller Credits | Soundtrack | Codes | Walkthrough
A Game Of Concentration is a game released for the Atari 2600. It is also released as Hunt & Score.

## Gameplay

.It is your standard game of concentration, where you must match up two cards of the same image and have more matches than your opponent.^ Then your son or daughter looks up at you with a quivering voice and asks, "Dad, why are we here?"
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

^ Big Fish Games Forums > All Game Forums > Concentration Try this game Find your game forum .

^ You would just be picked up and taken to the Alaskan-Siberian Asylum incommunicado and the state would also confiscate all of your personal and real property!
• CONCENTRATION CAMP PLANS FOR U.S. CITIZENS 10 February 2010 13:40 UTC www.greatdreams.com [Source type: Original source]

The game screen features either a 4 x 4 grid or a 5 x 6 grid of cards. You use the Keyboard Controller to select which card on the grid you want to flip over for a match.

# Simple English

File:Dilution-concentration simple
These glasses containing red dye show changes in concentration. The solutions on the left are more diluted, and the solutions on the right are more concentrated.

In chemistry, concentration is how much of a substance is mixed with another substance.

Substance that is dissolved (i.e. red dye in the example) is known as solute. Substance, in which solute is dissolved (i.e. water in the example) is known as solvent.

To concentrate a solution, one must add more solute, or reduce the amount of solvent. To dilute a solution, one must add more solvent, or reduce the amount of solute.

Simple English Wiktionary has the word meaning for:

# Citable sentences

Up to date as of December 22, 2010

Here are sentences from other pages on Concentration, which are similar to those in the above article.