How can concentration of water in a solution be decreased

Chemistry Solutions Percent Concentration. Alex D. Mar 16, The concentration can be decreased by 2 ways, by increasing the solute, or decreasing the water. You can use a process called dialysis to decrease the water in a solution. Place your solution in a dialysis bag. This bag should be made up of semipermeable substance.

If your tea was too bitter, you could add more sugar to increase the sweetness. Changing the amounts of solute and solvent directly effect the concentration of the solution. Related questions How can the concentration of water in solution be decreased? How do you find the concentration of a solution in ppm?

How do you make a 10 percent solution? How do you make a 2 percent solution? A serial dilution is a series of stepwise dilutions, where the dilution factor is held constant at each step. Key Terms dilution : a solution that has had additional solvent, such as water, added to make it less concentrated serial dilution : stepwise dilution of a substance in solution. Example mL of a 1. What is the final concentration of the diluted solution? Using Molarity in Calculations of Solutions Molarity is a unit of concentration; it is equal to moles of solute divided by the total volume of the solution in liters.

Learning Objectives Translate between molarity, grams of solute in solution, and volume of solution. Key Takeaways Key Points Molar concentration, also called molarity, is the number of moles of solute per liter of solution.

Molarity is the most common measurement of solution concentration. Do not confuse moles with molarity: molarity is a measure of concentration, while moles are a measure of the amount of substance. Key Terms molarity : The concentration of a substance in solution, expressed as the number moles of solute per liter of solution. Example 1 A student pipettes a mL sample of a 1. Example 2 What is the molarity of a solution containing 0.

Solution Stoichiometry Stoichiometry can be used to calculate the quantitative relationships between species in aqueous solution. Learning Objectives Calculate concentrations of solutions in molarity, molality, mole fraction and percent by mass and volume. Key Takeaways Key Points Stoichiometry deals with the relative quantities of reactants and products in chemical reactions. To calculate the quantity of a product, calculate the number of moles for each reactant. Moles of a product are equal to the moles of a limiting reactant in one-to-one reaction stoichiometry.

Key Terms stoichiometry : the study and calculation of quantitative measurable relationships of the reactants and products in chemical reactions chemical equations molarity : the concentration of a substance in solution, expressed as the number moles of solute per liter of solution molality : the concentration of a substance in solution, expressed as the number of moles of solute per kilogram of solvent.

What is the mass of AgCl s formed in the precipitation reaction? In general polar solvents dissolve polar solutes whereas nonpolar solvents will dissolve nonpolar solutes. Overall, the solution process depends on the strength of the attraction between the solute particles and the solvent particles. For example, water is a highly polar solvent that is capable of dissolving many ionic salts.

Note that when ionic compounds dissolve in a solvent they break apart into free floating ions in solution. This enables the compound to interact with the solvent. In the case of water dissolving sodium chloride, the sodium ion is attracted to the partial negative charge of the oxygen atom in the water molecule, whereas the chloride ion is attracted to the partial positive hydrogen atoms. When an ionic salt, such as sodium chloride, shown in A , comes into contact with water, the water molecules dissociate the ion molecules of the sodium chloride into their ionic state, shown as a molecular model in B the solid crystalline lattice of sodium chloride, and C the sodium chloride dissolved in the water solvent.

Photo of sodium chloride provided by Chris Many ionic compounds are soluble in water, however, not all ionic compounds are soluble. Ionic compounds that are soluble in water exist in their ionic state within the solution. You will notice in Figure 7. For ionic compounds that are not soluble in water, the ions are so strongly attracted to one another that they cannot be broken apart by the partial charges of the water molecules.

The following table can be used to help you predict which ionic compounds will be soluble in water. The dissociation of soluble ionic compounds gives solutions of these compounds an interesting property: they conduct electricity. Because of this property, soluble ionic compounds are referred to as electrolytes.

Many ionic compounds dissociate completely and are therefore called strong electrolytes. Sodium chloride is an example of a strong electrolyte. Some compounds dissolve but dissociate only partially, and solutions of such solutes may conduct electricity only weakly.

These solutes are called weak electrolytes. Solutes that dissolve into individual neutral molecules without dissociation do not impart additional electrical conductivity to their solutions and are called nonelectrolytes. Polar covalent compounds, such as table sugar C 12 H 22 O 11 , are good examples of nonelectrolytes. The term electrolyte is used in medicine to mean any of the important ions that are dissolved in aqueous solution in the body.

Sports drinks such as Gatoraid have combinations of these key electrolytes, to help replenish electrolyte loss following a hard workout. Similarly, solutions can also be made by mixing two compatible liquids together. The liquid in the lower concentration is termed the solute, and the one in higher concentration the solvent. When two similar solutions are placed together and are able to mix into a solution, they are said to be miscible.

Liquids that do not share similar characteristics and cannot mix together, on the other hand, are termed immiscible. For example, the oils found in olive oil, such as oleic acid C 18 H 34 O 2 have mainly nonpolar covalent bonds which do not have intermolecular forces that are strong enough to break the hydrogen bonding between the water molecules. Thus, water and oil do not mix and are said to be immiscible.

Other factor such as temperature and pressure also affects the solubility of a solvent. Thus, in specifying solubility, one should also be aware of these other factors. When considering the solubility solids, the relationship of temperature and solubility is not simple or predictable. Although the solubility of a solid generally increases with increasing temperature, there is no simple relationship between the structure of a substance and the temperature dependence of its solubility.

Many compounds such as glucose and CH 3 CO 2 Na exhibit a dramatic increase in solubility with increasing temperature. Solubility may increase or decrease with temperature; the magnitude of this temperature dependence varies widely among compounds. The variation of solubility with temperature has been measured for a wide range of compounds, and the results are published in many standard reference books.

Chemists are often able to use this information to separate the components of a mixture by fractional crystallization , the separation of compounds on the basis of their solubilities in a given solvent. According to the temperature curves in Figure 7. The crystals can then be separated by filtration. Fractional crystallization is a common technique for purifying compounds as diverse as those shown in Figure 7.

For the technique to work properly, the compound of interest must be more soluble at high temperature than at low temperature, so that lowering the temperature causes it to crystallize out of solution. In addition, the impurities must be more soluble than the compound of interest as was KBr in this example and preferably present in relatively small amounts.

The solubility of gases in liquids is much more predictable. The solubility of gases in liquids decreases with increasing temperature, as shown in Figure 7. Attractive intermolecular interactions in the gas phase are essentially zero for most substances, because the molecules are so far apart when in the gaseous form.

When a gas dissolves, it does so because its molecules interact with solvent molecules. Heat is released when these new attractive forces form. Thus, if external heat is added to the system, it overcomes the attractive forces between the gas and the solvent molecules and decreases the solubility of the gas. The solubilities of gases decrease with increasing temperature. The decrease in the solubilities of gases at higher temperatures has both practical and environmental implications. Anyone who routinely boils water in a teapot or electric kettle knows that a white or gray deposit builds up on the inside and must eventually be removed.

The problem is not a uniquely modern one: aqueducts that were built by the Romans years ago to carry cold water from alpine regions to warmer, drier regions in southern France were clogged by similar deposits. The chemistry behind the formation of these deposits is moderately complex, but the driving force is the loss of dissolved carbon dioxide CO 2 from solution. A solution of bicarbonate ions can react to form carbon dioxide, carbonate ion, and water:. Heating the solution decreases the solubility of CO 2 , which escapes into the gas phase above the solution.

In the presence of calcium ions, the carbonate ions precipitate as insoluble calcium carbonate, the major component of boiler scale. Calcium carbonate CaCO 3 deposits in hot water pipes can significantly reduce pipe capacity. These deposits, called boiler scale, form when dissolved CO 2 is driven into the gas phase at high temperatures.

In thermal pollution , lake or river water that is used to cool an industrial reactor or a power plant is returned to the environment at a higher temperature than normal. Because of the reduced solubility of O 2 at higher temperatures Figure 7.

Fish and other aquatic organisms that need dissolved oxygen to live can literally suffocate if the oxygen concentration of their habitat is too low. Because the warm, oxygen-depleted water is less dense, it tends to float on top of the cooler, denser, more oxygen-rich water in the lake or river, forming a barrier that prevents atmospheric oxygen from dissolving.

Eventually even deep lakes can be suffocated if the problem is not corrected. Additionally, most fish and other nonmammalian aquatic organisms are cold-blooded, which means that their body temperature is the same as the temperature of their environment. Temperatures substantially greater than the normal range can lead to severe stress or even death. Cooling systems for power plants and other facilities must be designed to minimize any adverse effects on the temperatures of surrounding bodies of water.

In the Pacific Northwest, salmonid populations are extremely susceptible to changes in water temperature. Within these population, optimal water temperatures are between In addition to reduced oxygen levels, salmon populations are much more susceptible to disease, predation, and parasite infections at higher water temperatures. Thus, thermal pollution and global climate change are creating real challenges to the survival and maintenance of these species.

A similar effect is seen in the rising temperatures of bodies of water such as the Chesapeake Bay, the largest estuary in North America, where global warming has been implicated as the cause. For each 1. Many marine species that are at the southern limit of their distributions have shifted their populations farther north.

In , the eelgrass, which forms an important nursery habitat for fish and shellfish, disappeared from much of the bay following record high water temperatures. Presumably, decreased oxygen levels decreased populations of clams and other filter feeders, which then decreased light transmission to allow the eelsgrass to grow.

The complex relationships in ecosystems such as the Chesapeake Bay are especially sensitive to temperature fluctuations that cause a deterioration of habitat quality. External pressure has very little effect on the solubility of liquids and solids. In contrast, the solubility of gases increases as the partial pressure of the gas above a solution increases. This point is illustrated in Figure 7. Because the concentration of molecules in the gas phase increases with increasing pressure, the concentration of dissolved gas molecules in the solution at equilibrium is also higher at higher pressures.

When the concentration of dissolved gas molecules has increased so that the rate at which gas molecules escape into the gas phase is the same as the rate at which they dissolve, a dynamic equilibrium has been established, as depicted here. Although the gas concentration may be expressed in any convenient units, we will use molarity exclusively. All Khan Academy content is available for free at www. As the data in Table 7. For a series of related substances, London dispersion forces increase as molecular mass increases.

The table also shows that O 2 is almost twice as soluble as N 2. Although London dispersion forces are too weak to explain such a large difference, O 2 is paramagnetic and hence more polarizable than N 2 , which explains its high solubility. Note: When a substance is paramagnetic it is very weakly attracted by the poles of a magnet, but does not retain any permanent magnetism.

This is important in many aspects of life including medicine where blood gases, like oxygen and carbon dioxide are commonly measured. Since partial pressure and concentration are directly proportional, if the partial pressure of a gas changes while the temperature remains constant, the new concentration of the gas within the liquid can be easily calculated using the following equation:. Where C 1 and P 1 are the concentration and partial pressure, respectively, of the gas at the initial condition, and C 2 and P 2 are the concentration and partial pressure, respectively, of the gas at the final condition.

For example, bubbles of CO 2 form as soon as a carbonated beverage is opened because the drink was bottled under CO 2 at a pressure greater than 1 atm. When the bottle is opened, the pressure of CO 2 above the solution drops rapidly, and some of the dissolved gas escapes from the solution as bubbles.

To increase the O 2 concentration in internal fluids, organisms synthesize highly soluble carrier molecules that bind O 2 reversibly. For example, human red blood cells contain a protein called hemoglobin that specifically binds O 2 and facilitates its transport from the lungs to the tissues, where it is used to oxidize food molecules to provide energy.

The concentration of hemoglobin in normal blood is about 2. Synthetic oxygen carriers based on fluorinated alkanes have been developed for use as an emergency replacement for whole blood.

Some ionic solids will accept a small number of water molecules into their crystal lattice structure and remain in a solid state. These solids are called solid hydrates. Solid hydrates contain water molecules combined in a definite ratio as an integral part of the crystal that are either bound to a metal center or that have crystallized with the metal complex. Such hydrates are also said to contain water of crystallization or water of hydration. A colorful example is cobalt II chloride, which turns from blue to red upon hydration, and can therefore be used as a water indicator.

Notice that the water molecules shown in red oxygen and white hydrogen are integrated into the crystal lattice of the cobalt II chloride, shown in blue cobalt and green chloride , based on polarity. The partially negative oxygen atoms are attracted to the positively charged cobalt while the partially positive hydrogen atoms are attracted to the negatively charged chloride ions.

Images provided by Wikipedia Commons upper left and lower left , Benjah-bmm27 upper right , and Smokefoot lower right. The n is usually a low integer, though it is possible for fractional values to occur. For example, in a monohydrate n is one, and in a hexahydrate n is 6.

For the example in Figure 7. Numerical prefixes of Greek origin that are used to designate solid hydrates are:. A hydrate which has lost water is referred to as an anhydride ; the remaining water, if any exists, can only be removed with very strong heating. A substance that does not contain any water is referred to as anhydrous. Some anhydrous compounds are hydrated so easily that they will pull water out of the atmosphere and become hydrated. These substances are said to be hygroscopic and can be used as drying agents or desiccants.

In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. All of us have a qualitative idea of what is meant by concentration. Anyone who has made instant coffee or lemonade knows that too much powder gives a strongly flavored, highly concentrated drink, whereas too little results in a dilute solution that may be hard to distinguish from water.

Quantitatively, the concentration of a solution describes the quantity of a solute that is contained in a particular quantity of that solution.