5A1 Types of Solutions Flashcards
Define and classify solutions into categories such as dilute, concentrated, saturated, or supersaturated.
What is a solution?
A homogeneous mixture of two or more substances (solutes) dissolved in another (solvent).
Examples: Salt in water or carbon in steel.
Solutions can be unsaturated, saturated, or supersaturated.
What are the two components of a solution?
- Solute
- Solvent
The solute is what is dissolved within the solvent.
True or False:
A solution can only be a liquid.
False
Solutions can exist in gas, liquid, or solid phases. Examples include air (gas) and steel (solid).
What is an example of a solid dissolved in a solid?
Bronze
Tin dissolved in copper
Alloys like bronze, brass, and stainless steel are examples of solid solutions.
What is the saturation point?
The point of maximum concetration where a solution cannot dissolve any more of a substance.
This point depends on temperature and the nature of the solution components. After the saturation point, any additional subtance will become precipitate since it cannot be dissolved.
Define:
unsaturated solution
A solution where the amount of solute is below the saturation point at a given temperature.
Unsaturated solutions can dissolve more solute until they reach saturation.
Fill in the blank:
A solution is saturated when the solute’s concentration is _______ its solubility.
equal to
Saturation occurs when the solution reaches equilibrium with the dissolved solute.
What is an example of a gaseous unsaturated solution?
Mist
Water in the air
Mist consists of tiny water droplets dispersed in air.
Fill in the blank:
Vinegar is an example of an unsaturated solution composed of _______ _____ as the solute and water as the solvent.
acetic acid
Acetic acid is dissolved in water to make vinegar.
What is a concentrated solution?
A solution where the solute concentration is at or near its maximum solubility.
Solubility defines the maximum solute amount that can dissolve in a solvent under specific conditions.
What happens when a solute is added to a saturated solution?
It does not dissolve, and acts as a precipitate.
A saturated solution has reached its maximum solubility for the solute, meaning that any additional solute cannot be dissolved.
Which gas is the solvent in air?
Nitrogen
Air is a gaseous solution with nitrogen as the solvent and gases like oxygen, argon, and carbon dioxide as solutes.
Define:
dilute solution
A solution with solute concentrations significantly lower than their solubility.
Example: Tea contains low concentrations of organic and inorganic compounds.
How is seawater an example of a concentrated solution?
Seawater has high concentrations of salts like sodium, potassium, and magnesium dissolved in water.
Seawater is saturated with various salts, making it a concentrated solution.
Fill in the blank:
_______ _____ is a concentrated solution of sulfuric acid used in batteries.
Battery acid
Concentrated solutions are used in various industries for specific purposes.
How do concentrated solutions differ from dilute solutions?
Concentrated solutions have solute concentrations near maximum solubility, while dilute solutions do not.
Example: Syrup (concentrated) vs. tea (dilute).
Fill in the blank:
A solution made by dissolving carbon in iron is called _______.
steel
Steel is an example of a solid-phase solution commonly used in construction.
How does a solution become supersaturated?
By exceeding its solubility limit, often through cooling or evaporation, with kinetic barriers preventing crystallization.
Supersaturation can be achieved by heating a solute to dissolve more and then cooling the solution without nucleation occurring.
What is dynamic equilibrium in the context of solutions?
A state where opposing processes, like dissolution and crystallization, occur simultaneously at equal rates.
In saturated solutions, solutes and solvents are in dynamic equilibrium.
True or False:
A supersaturated solution is in dynamic equilibrium.
False
Supersaturated solutions are metastable and not in dynamic equilibrium, unlike saturated solutions.
List three characteristics of supersaturated solutions.
- Solute concentration exceeds solubility.
- The solution is metastable.
- Crystallization or condensation is kinetically inhibited.
These features distinguish supersaturated solutions from saturated ones.
Fill in the blank:
_______ barriers prevent nucleation in supersaturation.
Kinetic
Kinetic barriers require specific conditions, like seed crystals, to be overcome.
What is nucleation?
The initial process where solute comes out of a solution to form crystals or droplets.
It often requires energy and is a limiting step in crystallization.
Why do sugar crystals form in supersaturated solutions?
Seed crystals provide nucleation sites, allowing sugar to crystallize and reestablish equilibrium.
The process can be demonstrated by cooling a sugar solution with a string or stick placed inside.
What happens during evaporation of a saturated salt solution?
Solvent is removed, increasing solute concentration, eventually leading to supersaturation.
Salt fields use this process to harvest salt by allowing seawater to evaporate.
True or False:
Supersaturated solutions are used in drug delivery systems.
True
Supersaturation enhances drug bioavailability by maintaining higher concentrations than solubility permits.
How do sodium acetate hand warmers work?
A supersaturated sodium acetate solution crystallizes upon activation, releasing heat in an exothermic reaction.
The activation is usually triggered by introducing a seed, like a metal disc.
What role does temperature play in supersaturation?
Higher temperatures increase solubility, allowing more solute to dissolve before cooling to achieve supersaturation.
Example: Dissolving sugar in water at high temperatures and cooling without crystallization.
Which gas is supersaturated in carbonated beverages?
Carbon dioxide
(CO₂)
High pressure dissolves more CO₂, which is released as bubbles when the bottle is opened.
What phase change occurs when raindrops form from supersaturated air masses?
Gas (vapor) to liquid
Supersaturation in cooler regions leads to condensation and raindrop formation.
Define:
dilution
The process of decreasing the concentration of a solute by increasing the amount of solvent.
Dilution is used in chemical reactions, manufacturing, and biomedical research.
Which formula is used for dilution calculations?
M₁V₁ = M₂V₂
This formula relates the concentrations and volumes of the initial and final solutions.
Calculate the volume of stock solution needed to prepare 1 L of 2 M solution from a 4M solution.
0.5 L
Use M₁V₁ = M₂V₂ to find V₁.
M₁ = 4M, M₂ = 2M, and V₂ = 1L.
Define:
serial dilution
A series of stepwise dilutions of a concentrated solution to create progressively more dilute solutions.
Commonly used in laboratories, especially in microbiology.
List the steps for diluting a solution.
- Add partial solvent.
- Add stock solution.
- Add remaining solvent to desired volume.
Safety measures like PPE and correct flask use are essential.
True or False:
Adding water to acid is the correct method for dilution.
False
Acid must be added to water due to the exothermic reaction.
What equipment is essential for diluting a solution?
- Volumetric flask
- Funnel
- PPE
- Calculator
Ensures accuracy and safety during the dilution process.
How do you calculate the dilution factor?
Dilution Factor = V₂/V₁ = M₁/M₂
This relates the volumes or molarities of initial and final solutions.
Dilution factor helps determine how much a solution is diluted.
What is the dilution factor if 10 mL of a solution is diluted to 100 mL?
10
Dilution Factor= V₂/V₁ = 100/10=10.
How is a solution concentrated?
- By adding more solute.
- By removing solvent.
Example: Evaporating water increases solute concentration.
True or False:
Dilution decreases the amount of solute in the solution.
False
Dilution only decreases the concentration, not the total amount of solute.
What precautions are needed for diluting volatile chemicals?
- Use a ventilated hood.
- Wear PPE.
- Follow MSDS guidelines.
Ensures safety when working with toxic or reactive substances.
How much solvent is needed to dilute 62.5 mL of 10% KCl to 125 mL of 5%?
62.5 mL
Solvent = Final volume - Volume of stock solution.
What is molarity (M)?
It is the moles of solute per liter of solution.
Molarity formula: M=moles of solute/liters of solution.
What is molality (m)?
It is the moles of solute per kilogram of solvent.
Molality formula: m=moles of solute/kilograms of solvent.
Fill in the blank:
The units of molarity are _____.
mol/L
Molarity uses the units moles of solute per liter of solution.
Fill in the blank:
The units of molality are _____.
mol/kg
Molality uses the units moles of solute per kilogram of solvent.
What is the effect of temperature on molarity and molality?
Temperature affects molarity but not molality.
Molarity depends on volume, which can expand or contract with temperature.
Molality depends on the mass of the solvent, which does not change with temperature.
How do you convert milliliters (mL) to liters (L)?
Divide the volume in mL by 1000.
Example: 175 mL/1000=0.175 L.
How do you convert grams (g) to kilograms (kg)?
Divide the mass in grams by 1000.
Example: 375 g/1000=0.375 kg.
