What molecular compounds have high solubility in water? Which ones have low solubility in water?
Molecular compounds that are polar and have hydrogen bonding tend to have higher solubility in water. Meanwhile, non polar molecular substances tend to habe low solubility in water.
How do you write the chemical formula for a solubility equilibrium established by mixing two solutions, each with a high concentration of respective ions?
How do you write the chemical formula for a solubulity equilibrium established by adding a solute to a solvent?
Wha does the kinetic molecular theory state? How does this apply to saturated solutions?
According to the kinetic molecular theory, particles are always moving and collisions are always occuring even if no changes are observed. A saturated solution is in a state of dynamic equilibrium- dissolving and crystallization are taking place at the same rate; thus, the concentration and the quanitity of solid present do not change. The molecular theory connects to this because it this constant movement and colliding which is causing the dynamic equilibrium seen, where crystallization and dissolution are taking place at the same time.
What do the major entities present when a substance is placed in water depend on?
The solubility of the substance.
When would a non-polr molecular compound have a high solubility?
When it is in a non polar solvent.
Most ionic compounds dissolve in water to some extent. How can you know if an ionic compound is highly solubule in water or if it is not that solubule in water.
Ionic compounds with solubility greater than or equal to 0.1 mol/L are highly soluble in water. Meanwhile, substances with solubility less than 0.1 mol/L are slightly soluble/not very soluble in water
You can find this value by referencing the solubility table in the data booklet.
True or false:
Elements are highly solubule in water
False. Elements generally have low solubility in water.
Describe the best conditions for solubility in water for solids, gases, and liquids.
Solids: tend to have higher solubility in water at higher temperatures
Gases: Tend to have higher solubility in water at low temperatures and high pressure
Liquids: tend to have higher solubility in water at higher temperatures. (However, some liquids, usually are non polar, are immiscible with water- they do not dissolve to an appreciable extent. Meanwhile, some liquids, usually polar liquids and liquids with hydrogen bonding, are miscible with water- they dissolve completely in water regardless of the quantities mixed.)
What is solubility dependent on?
Solubility depends on temperature, pressure, and the chemical properties of the solute and solvent, such as polarity.
Describe saturated, un-saturated, and super saturated solutions:
Saturated: A saturated solution is a solution in which no more solute will dissolve at a specified temperature; the solution is at maximum concentration.
Un-saturated: An unsaturated solution is a solution in which more solute can be dissolved into the solvent at a specific temperature.
Super saturated: A super saturated solution is a solution where more solute has been added at a higher temp and then cooled to allow for more solute than normally at saturation at the cooled temperature.
How do you calculate the total energy change in a dissolution reaction?
When is dissolution endothermic? When is it exothermic?
Dissolution is endothermic if, empirically, energy is absorbed from the surroundings. Theoretically, dissolution is endothermic if more energy is absorbed to break bonds than is released when new bonds form. However, Dissolution is exothermic if empirically, energy is released to the surroundings. Theoretically, less energy is absorbed to break bonds than is released when new bonds form.
Describe the difference between an ionic compound dissolving and a molecular compound dissolving.
With ionic compounds, the actual molecule breaks apart (Ex. NaCl breaks into sodium ions and chlorine ions). Additionally, the solute and solvent are attracted due to opposite charges. Meanwhile, with molecular compounds, the actual molecule does not break apart, it jsut breaks into smaller chunks (Ex. big chunk of sucrose break into tinier chunks of sucrose). Additionally, the bonds between the solute and solvent are made up of intermolecular forces such as the london dispersion force, the hydrogen bonds, and dipole dipole attractions.
Describe the process of dissolving:
1. the bonds between the particles in the solute break- this process is always endothermic (more energy put in to break bonds then is released when bonds actually break)
2. Some of the intermolecular forces between the particles in the solvent also break- this process is always endothermic
3. the attraction between the particles of the solute and the particles of the solvent result in the formation of new chemical bonds- this process is always exothermic (more energy released when bonds form than put in to actually form the bonds)
Describe if each type of compound form electrolytic solutions or not.
Molecular compounds: Form nonelectrolytic solutions (except acids) because the entities disperse as neutral molecules.
Ionic compounds: Form electrolytic solutions because the dissociate inot individual anions and cations.
Acids: Form electrolytic solutions because they ionize to form anions and hydrogen ions
Bases: Form electrolytic solutions because the dissociate into cations and hydroxide ions or they react with water to produce hydroxide ions.
When is a compound an electrolyte? when is it a nonelectrolyte?
Compounds are electrolytes if their aqueous solutions conduct electricity. They are nonelectrolytes if their aqueous solutions do not conduct electricity.
Define dissolution, dissociation, and ionization.
dissolution: is the process in which individual entities of a solute disperse througout a solvent.
dissociation: is the seperation of an ionic compound into ions
ionization:is the process by which an electrically neutral atom or molecule is converted to an ion/ions; acids ionize in water.
What is often a prerequisite for chemical change? why?
Dissolving substances in water is often a prerequsite for chemical change. Some chemicals do not react untill in a solution where there is increased contact between the reacting ntities.
What are solutions composed of? What is a solute? What is a solvent?
Solutions are composed of atleast one solute (can be solid, liquid, or gas) and one solvent (can be solid, liquid, or gas)
solute: the substance that is dissolved
solvent: the medium in which the solute is dissolved
Diffrentiate between dissociation, solvation, and hydration.
dissociation: ionic compound breaks apart and each ion binds to an H20 molecule.
solvation: ion and H20 molecule move together.
hydration: ion is surrounded by multiple H20 molecules.
When all chemicals are different states of matter, what should we do to calculate the molar concentration of ions in solution?
We should convert any values into moles and use the molar ration to find the moles of other substances, from there, we can find theose substance's molar concentrations.
When, all chemicals are aqueous, how can we calculate the molar concentration of ions in a solution?
use the arrow way or use
c required= c given multipled by coefficent of required over coefficent of given
What is the mole ratio of a balanced chemical equation proportional to?
the molar concentration of ions in solution when a high solubility ionic compound dissociates or a strong acid ionizes.
How do you calculate parts per million concentration?
Note: if the units are already 10^6 apart, then you do not need to multiply by 10^6
Define parts per million concentration:
Parts per million concentration is the number of units of mass of mass of solute per million units total of solution. (solute is always mass while solvent can be mass or volume)
How do you calcuate each type of percent concentration?
Define each type of percent concentration:
Percent mass by volume concentration: is the ratio of the mass of solute that is present in a solution, relative to the volume of the solution as a whole.
Percent mass by mass concentration: is the ratio of the mass of solute that is present in solution, relative to the mass of the solution as a whole.
Percent volume by volume concentration: is the ratio of the volume of solute that is present in a solution, relative to the volume of the solution as a whole.
*Note* when calculating percent concentration, the solute and solution units must be equal to one another. (for water, due to it's density properties, 1mL=1g and 1L=1kg)
What is percent concentration?
percent concentration is a measure of the number of units of solute per 100 units of solution.
How much is one M equal to?
1 mol/L
What is a unique way that molar concentration can be indicated?
Molar concentration can be indicated by the use of square brackets.
ex. [NaCl (aq)] means the molar concentration of sodium chloride.
How do you calculate molar concentration?
How do you calculate for concentration?
What is molar concentration/amount concentration? What is the unit for this type of concentration?
Molar concentration, or amount concentration, is the chemical amount of solute dissolved in one litre of solution.
The unit for this type of concetration is the mol/L or the M.
What is concentration (c)?
Concentration (c) is a ratio that compares the quantity of solute to the quantity of solution.
The constant quantity of solute can be expressed in terms of the volume and concentration of solution. How?
Note: any units can be used for concentration and volume, as long as they are consistent
Is concentration inversley proportional or proportionally related to the volume?
inversley proportional
What is the "stock solution"
the solution before dilution.
True or false: the mass and chemical amount of solute is different before and after dilution.
False, the mass and chemical amount of solute is the same before and after dilution.
How do you prepare a standard solution by dilution?
1. Use a volumetric pipette to measure the required volume of stock solution
2. transfer the volume of stock solution into a volumetric flask calibrated to measure the final volume of diluted solution
3. add deionized water to the calibration line, adding dropwise whe the solution is close to the line
4. Invert the flask several times to mix.
What is dilution?
Dilution is the process of adding water to decrease the concentration of a solution.
How do you prepare a standard solution from a solid?
1. Calculate the mass of solid required to make a particular volume of solution of a particular concentration.
2. Measure the required mass of solute using an electronic balance
3. Place the solute in a beaker and dissolve in approximatley half of the final solution volume of deionized water.
4. Use a funnel to transfer the solution to a volumetric flask calibrated to measure the desired volume of solution.
5. Rinse the beaker and stirring rod three times with deionized water and transfer rinse water to the flask to ensure all solute has been transferred. Rinse the funnel.
6. Add deionized water to the calibration line, addiing dropwise when the solution is close to the line
7. invert the flask several times to mix.
What is a standard solution?
A standard solution is a solution of an accuratley known concentration (helps us analyze a substance)
