5A2 Solubility and Dissolving Factors Flashcards
Explain factors affecting solubility and rate of dissolving, such as temperature, pressure, and particle size.
Define:
dissolution
It is the process where a solute dissolves in a solvent to form a homogeneous mixture (solution).
Dissolution involves the breakdown of solute particles into ions or molecules, evenly distributed in solvent.
List two examples of covalent compounds dissolving in water.
- Ammonia
- Chlorine gas
Covalent compounds disintegrate into their components when added to water.
What is an example of an ionic compound dissolving in water?
Sodium chloride
(salt)
Ionic compounds break down into negative and positive ions in water.
Which solute dissolves in water without breaking covalent bonds?
Table sugar
(C₁₂H₂₂O₁₁)
Water interrupts intermolecular forces but not the covalent bonds in sugar.
Define:
rate of solution
It is the speed at which a solute dissolves in a solvent.
Factors like temperature, agitation, and solute particle size influence the rate of solution.
What factors affect the rate of dissolution?
- Polarity
- Surface area
- Temperature
- Pressure
These factors influence how quickly a solute dissolves in a solvent.
What is the effect of polarity on dissolution?
Polar solvents dissolve polar solutes, and non-polar solvents dissolve non-polar solutes
Like dissolves like.
Define:
miscible liquids
Liquids that dissolve completely in each other to form a homogeneous mixture.
Example: Ethanol and water.
True or False:
Oil and water are miscible.
False
Oil and water are immiscible because they have different polarities. Hence the saying, “oil and water don’t mix”!
How does temperature affect the rate of dissolution?
Higher temperature increases kinetic energy, leading to more frequent and stronger collisions with solute molecules.
Sugar dissolves more quickly in hot tea than in cold tea.
Fill in the blank:
Granulated sugar dissolves faster than a sugar cube due to its larger _______ _____.
surface area
Larger surface area increases the frequency of collisions with solvent molecules.
Define:
solubility
The maximum amount of solute that can dissolve in a solvent at a specific temperature to form a saturated solution.
It determines how much solute a solvent can hold before saturation occurs.
Define:
solubility limit
It is the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature.
Any additional solute will not dissolve beyond this limit.
Which factors can affect solubility?
- Temperature
- Pressure
- pH
- Stirring/agitation
- Particle size
These factors influence how easily a solute dissolves in a solvent.
Fill in the blank:
The solubility of a substance is expressed in _______ per 100 grams of solvent.
grams of solute
What is the solubility of NaCl as temperature increases?
It remains fairly constant as temperature increases.
Unlike many other solutes, the solubility of NaCl does not significantly change with temperature.
True or False:
Gases dissolve better in liquids at higher temperatures.
False
For gases, solubility decreases with an increase in temperature due to higher kinetic energy causing gas molecules to escape.
What happens to a saturated solution if its temperature increases?
It becomes unsaturated.
Increasing the temperature increases the solubility of most solutes, allowing more solute to dissolve.
True or False:
Solubility of liquids increases with temperature.
True
Heating increases molecular motion, enabling solutes to dissolve more readily in liquid solvents.
Higher temperatures also weaken intermolecular forces in the solute.
How does solute particle size affect solubility?
Smaller particles dissolve faster due to their larger surface area in contact with the solvent.
Larger surface areas provide more opportunity for solvent interactions.
How does stirring/agitation affect solubility?
It increases the rate of solubility by bringing more solute particles into contact with the solvent.
It does not change the solubility limit but speeds up the dissolving process.
What is a key factor affecting the solubility of gases in solutions?
Pressure
Increasing pressure can increase the solubility of gases in solvents.
Example: Carbon dioxide in carbonated beverages under pressure.
Which law relates pressure to solubility of gases?
Henry’s Law
It dictates that the solubility of a gas is directly proportional to its partial pressure.
Why does nitrogen dissolve in a scuba diver’s blood?
High pressure under water increases nitrogen solubility in the bloodstream.
Sudden pressure changes can cause nitrogen to diffuse rapidly, leading to decompression sickness.
How does the polarity of water contribute to salt dissolution?
Water’s polar molecules attract the positive and negative ions in salt, separating them.
The oxygen in water aligns with Na⁺, while hydrogen aligns with Cl⁻.
What happens to carbon dioxide in an open carbonated beverage?
It escapes as pressure decreases, forming bubbles and making the drink go flat.
Pressure maintains CO₂ solubility; reduced pressure leads to gas release.
True or False:
The solubility limit can be changed by increasing the solvent volume.
False
The solubility limit at a given temperature is fixed for each solute-solvent combination.
What is a solubility curve?
A graph showing the relationship between solute and solvent at different temperatures.
It indicates the maximum solubility limit for each temperature.
What does a downward sloping solubility curve indicate?
That solubility decreases as temperature increases.
This is an exception, as most solubility curves slope upward.
What is the customary unit for temperature on a solubility curve?
Degrees Celsius
(°C)
Temperature is always measured in Celsius on a solubility curve.
How can you read a solubility curve?
- Find the temperature on the X-axis.
- Follow it up to the curve to determine the solubility.
Alternatively, you can find the solute amount on the Y-axis and determine the corresponding temperature.
What is one industrial application of solubility curves?
Creating accurate metal alloys by determining the solubility of metals at specific temperatures.
Solubility graphs help predict the behavior of solutes in various solvents.
True or False:
Solubility curves can help determine which solute will crystallize first.
True
By comparing solubility at different temperatures, you can predict which solute will crystallize first.
