5A1 Types of Solutions

Question 1

What is a solution?

Answer 1

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.

Question 2

What are the two components of a solution?

Answer 2

1. Solute
2. Solvent

The solute is what is dissolved within the solvent.

Question 3

True or False:

A solution can only be a liquid.

Answer 3

False

Solutions can exist in gas, liquid, or solid phases. Examples include air (gas) and steel (solid).

Question 4

What is an example of a solid dissolved in a solid?

Answer 4

Bronze

Tin dissolved in copper

Alloys like bronze, brass, and stainless steel are examples of solid solutions.

Question 5

What is the saturation point?

Answer 5

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.

Question 6

Define:

unsaturated solution

Answer 6

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.

Question 7

Fill in the blank:

A solution is saturated when the solute’s concentration is _______ its solubility.

Answer 7

equal to

Saturation occurs when the solution reaches equilibrium with the dissolved solute.

Question 8

What is an example of a gaseous unsaturated solution?

Answer 8

Mist

Water in the air

Mist consists of tiny water droplets dispersed in air.

Question 9

Fill in the blank:

Vinegar is an example of an unsaturated solution composed of _______ _____ as the solute and water as the solvent.

Answer 9

acetic acid

Acetic acid is dissolved in water to make vinegar.

Question 10

What is a concentrated solution?

Answer 10

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.

Question 11

What happens when a solute is added to a saturated solution?

Answer 11

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.

Question 12

Which gas is the solvent in air?

Answer 12

Nitrogen

Air is a gaseous solution with nitrogen as the solvent and gases like oxygen, argon, and carbon dioxide as solutes.

Question 13

Define:

dilute solution

Answer 13

A solution with solute concentrations significantly lower than their solubility.

Example: Tea contains low concentrations of organic and inorganic compounds.

Question 14

How is seawater an example of a concentrated solution?

Answer 14

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.

Question 15

Fill in the blank:

_______ _____ is a concentrated solution of sulfuric acid used in batteries.

Answer 15

Battery acid

Concentrated solutions are used in various industries for specific purposes.

Question 16

How do concentrated solutions differ from dilute solutions?

Answer 16

Concentrated solutions have solute concentrations near maximum solubility, while dilute solutions do not.

Example: Syrup (concentrated) vs. tea (dilute).

Question 17

Fill in the blank:

A solution made by dissolving carbon in iron is called _______.

Answer 17

steel

Steel is an example of a solid-phase solution commonly used in construction.

Question 18

How does a solution become supersaturated?

Answer 18

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.

Question 19

What is dynamic equilibrium in the context of solutions?

Answer 19

A state where opposing processes, like dissolution and crystallization, occur simultaneously at equal rates.

In saturated solutions, solutes and solvents are in dynamic equilibrium.

Question 20

True or False:

A supersaturated solution is in dynamic equilibrium.

Answer 20

False

Supersaturated solutions are metastable and not in dynamic equilibrium, unlike saturated solutions.

Question 21

List three characteristics of supersaturated solutions.

Answer 21

1. Solute concentration exceeds solubility.
2. The solution is metastable.
3. Crystallization or condensation is kinetically inhibited.

These features distinguish supersaturated solutions from saturated ones.

Question 22

Fill in the blank:

_______ barriers prevent nucleation in supersaturation.

Answer 22

Kinetic

Kinetic barriers require specific conditions, like seed crystals, to be overcome.

Question 23

What is nucleation?

Answer 23

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.

Question 24

Why do sugar crystals form in supersaturated solutions?

Answer 24

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.

Question 25

What happens **during evaporation** of a saturated salt solution?

Answer 25

Solvent is removed, increasing solute concentration, eventually **leading to supersaturation**. ## Footnote Salt fields use this process to harvest salt by allowing seawater to evaporate.

Question 26

# True or False: Supersaturated solutions are **used in drug delivery** systems.

Answer 26

True ## Footnote Supersaturation enhances drug bioavailability by maintaining higher concentrations than solubility permits.

Question 27

How do sodium acetate **hand warmers** work?

Answer 27

A supersaturated **sodium acetate solution crystallizes** upon activation, **releasing heat** in an exothermic reaction. ## Footnote The activation is usually triggered by introducing a seed, like a metal disc.

Question 28

What role does **temperature** play in supersaturation?

Answer 28

**Higher temperatures increase solubility**, allowing more solute to dissolve before cooling to achieve supersaturation. ## Footnote Example: Dissolving sugar in water at high temperatures and cooling without crystallization.

Question 29

Which gas is supersaturated in **carbonated beverages**?

Answer 29

Carbon dioxide | (CO₂) ## Footnote High pressure dissolves more CO₂, which is released as bubbles when the bottle is opened.

Question 30

What **phase change** occurs when raindrops form from supersaturated air masses?

Answer 30

Gas (vapor) to liquid ## Footnote Supersaturation in cooler regions leads to condensation and raindrop formation.

Question 31

# Define: dilution

Answer 31

The process of **decreasing the concentration of a solute** by increasing the amount of solvent. ## Footnote Dilution is used in chemical reactions, manufacturing, and biomedical research.

Question 32

Which formula is used for **dilution calculations**?

Answer 32

M₁V₁ = M₂V₂ ## Footnote This formula relates the concentrations and volumes of the initial and final solutions.

Question 33

Calculate the volume of **stock solution needed** to prepare 1 L of 2 M solution from a 4M solution.

Answer 33

0.5 L ## Footnote Use M₁V₁ = M₂V₂ to find V₁. M₁ = 4M, M₂ = 2M, and V₂ = 1L.

Question 34

# Define: serial dilution

Answer 34

A series of **stepwise dilutions** of a concentrated solution to create progressively more dilute solutions. ## Footnote Commonly used in laboratories, especially in microbiology.

Question 35

List the **steps for diluting** a solution.

Answer 35

1. Add partial solvent. 1. Add stock solution. 1. Add remaining solvent to desired volume. ## Footnote Safety measures like PPE and correct flask use are essential.

Question 36

# True or False: Adding water to acid is the **correct method** for dilution.

Answer 36

False ## Footnote Acid must be added to water due to the exothermic reaction.

Question 37

What **equipment** is essential **for diluting** a solution?

Answer 37

* Volumetric flask * Funnel * PPE * Calculator ## Footnote Ensures accuracy and safety during the dilution process.

Question 38

How do you calculate the **dilution factor**?

Answer 38

Dilution Factor = V₂/V₁ = M₁/M₂ ## Footnote This relates the volumes or molarities of initial and final solutions. Dilution factor helps determine how much a solution is diluted.

Question 39

What is the dilution factor if 10 mL of a solution is **diluted to 100 mL**?

Answer 39

10 ## Footnote Dilution Factor= V₂/V₁ = 100/10=10.

Question 40

How is a solution **concentrated**?

Answer 40

* By adding more solute. * By removing solvent. ## Footnote Example: Evaporating water increases solute concentration.

Question 41

# True or False: Dilution decreases the **amount of solute** in the solution.

Answer 41

False ## Footnote Dilution only decreases the concentration, not the total amount of solute.

Question 42

What precautions are needed for **diluting volatile chemicals**?

Answer 42

* Use a ventilated hood. * Wear PPE. * Follow MSDS guidelines. ## Footnote Ensures safety when working with toxic or reactive substances.

Question 43

How much **solvent is needed** to dilute 62.5 mL of 10% KCl to 125 mL of 5%?

Answer 43

62.5 mL ## Footnote Solvent = Final volume - Volume of stock solution.

Question 44

What is **molarity** (M)?

Answer 44

It is the moles of **solute per liter** of solution. ## Footnote Molarity formula: M=moles of solute/liters of solution.

Question 45

What is **molality** (m)?

Answer 45

It is the moles of **solute per kilogram** of solvent. ## Footnote Molality formula: m=moles of solute/kilograms of solvent.

Question 46

# Fill in the blank: The **units** of molarity are \_\_\_\_\_.

Answer 46

mol/L ## Footnote Molarity uses the units moles of solute per liter of solution.

Question 47

# Fill in the blank: The **units** of molality are \_\_\_\_\_.

Answer 47

mol/kg ## Footnote Molality uses the units moles of solute per kilogram of solvent.

Question 48

What is the **effect of temperature** on molarity and molality?

Answer 48

Temperature **affects molarity but not molality**. ## Footnote 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.

Question 49

How do you convert **milliliters (mL) to liters (L)**?

Answer 49

**Divide** the volume in mL **by 1000**. ## Footnote Example: 175 mL/1000=0.175 L.

Question 50

How do you convert **grams (g) to kilograms (kg)**?

Answer 50

**Divide** the mass in grams **by 1000**. ## Footnote Example: 375 g/1000=0.375 kg.