Mixtures in Commercial Products (2.4) – Detailed Study Notes

Introduction

• Mixtures are encountered in everyday life and in commercial products; they are combinations of two or more pure substances where each substance retains its own properties.
• Mixtures can be classified by how uniformly the components are distributed and how many phases are present:
  • Homogeneous mixtures (solutions): single phase; uniform composition; components indistinguishable by eye.
  • Heterogeneous mixtures: more than one phase; composition and appearance vary throughout.
• In commercial contexts, mixtures are used and separated based on differences in physical and chemical properties of the constituents.
• This unit contrasts homogeneous vs heterogeneous mixtures, and discusses use, safety, quality, and cost implications for consumer products and industrial processes.

Learning Objectives

• Recognize the common homogeneous and heterogeneous mixtures found in commercial products.
• Compare these mixtures on the basis of use, safety, quality, and cost.
• DepEd Competencies:
  • Recognize the formulas of common chemical substances (STEM_GC11MP-Ia-b-9).
  • Compare consumer products on the basis of their components for use, safety, quality, and cost (STEM_GC11MP-Ia-b-11).

Warm Up

• Activity: Mixtures Found At Home! (5 minutes)
  • Bring any commercial product at home that is a mixture.
  • Read its label; identify main components.
  • Determine whether it is a homogeneous or heterogeneous mixture based on its appearance and component distribution.
  • If label does not reveal components, conduct prior research.
  • Answer the guide questions:
    1) Main components of your selected mixture?
    2) Is it homogeneous or heterogeneous? Basis for classification?
    3) Discuss the use of your chosen product.

Learn about It!: Mixtures for Commercial Use

• Mixtures are two or more pure substances physically combined; each substance retains its own properties and composition.
• Two broad classes:
  • Homogeneous mixtures (solutions): uniform composition; only one phase; components are well distributed and not observable by naked eye.
  • Heterogeneous mixtures: non-uniform composition; two or more phases; components can be visually distinguished.
• In homogeneous mixtures, a solution consists of two components: the solvent and the solute.
  • Solvent: the component in greater amount; dissolving medium.
  • Solute: the component present in lesser amount; substance being dissolved.
  • When a solute dissolves, it breaks into very small pieces and distributes evenly in the solvent, resulting in a consistent appearance throughout.
  • Particles of a solution are too small to be seen; they are indistinguishable from each other.
• In heterogeneous mixtures, components remain distinct and can be separated by physical methods.
• Compounds vs Mixtures:
  • Compounds: pure substances formed by chemical bonds; fixed ratios of elements; can be separated into simpler substances only by chemical methods.
  • Mixtures: physical combinations of substances; components retain their own chemical identities; separation is possible by physical methods.
• Summary relationships:
  • Mixtures have variable mass ratios; compounds have fixed ratios.
  • Mixtures can be separated into simpler substances by physical methods; compounds require chemical methods (reactions) to yield simpler substances.
• Visual takeaway: mixtures are everywhere in daily life; many commercial products are mixtures, and separation techniques exploit differences in properties of the constituents.

Common Homogeneous Mixtures in Commercial Products

• Homogeneous mixtures (solutions) include:
  • Vinegar: a liquid solution of acetic acid in water; about $4\%$ acetic acid by standard market formulations; law requires at least $4\%\,\text{acetic acid}$ in 100 mL of water.
  • Fish sauce (patis): a liquid salt solution; contains dissolved salts in water with fermentation products; US Department of Agriculture data notes about $7.851\text{ g}$ of sodium per some serving/amount (sodium content data point cited in this material).
  • Soft drinks, fruit juices: sugars dissolved in water; flavorings and colorings added; CO₂ forms gas bubbles; when poured, gas may separate visually, indicating heterogeneous portions (gas remnants).
  • Alcoholic beverages: ethanol in water; alcohol content varies by category:
  • Beer: $4.5\%$ ethanol (approx. $4.5\text{ mL} \text{ ethanol} ext{ per } 100\text{ mL}$)
  • Wine: $11.6\%$ ethanol
  • Liquor: $37\%$ ethanol
  • Medicines:
  • Liquid medicines (e.g., cough syrup): solutions; sometimes diluted with water as directed.
  • Tablets (e.g., paracetamol): solid solutions; tablet is a homogeneous mixture of the active ingredient and fillers; may weigh slightly more than the labeled amount due to fillers.
  • FDA regulation: medicines must be FDA-approved to ensure quality and safety.
  • Rubbing alcohol: typically a $70\%$ solution of either ethyl alcohol (ethanol) or isopropyl alcohol; rest is water; highly flammable.
  • Intravenous (IV) solutions: commonly include:
  • Dextrose (glucose) solutions: usually $5\%$ to $10\%$ dextrose in water.
  • Other IV fluids: saline (NaCl), insulin solutions, potassium chloride, etc. All are solutions.
• Important reminders:
  • Homogeneous mixtures have a single phase and are often called solutions.
  • The solvent is the component in greater amount; the solute is the component in lesser amount.
  • In solutions, particles are too small to observe and do not settle out.

Common Heterogeneous Mixtures in Commercial Products

• Heterogeneous mixtures have visible composition differences and can have two or more phases; examples include suspensions and colloids.
• Suspensions:
  • Ice in iced tea: ice does not dissolve and remains as a separate phase; upon settling, layers may form.
• Colloids (also called emulsions in some contexts):
  • Milk: colloid; fat droplets dispersed in water.
  • Beverages with added milk or egg-based emulsions may form colloidal mixtures.
  • Latte: milk is a colloid; when added to coffee, the overall mixture can be considered a colloidal mixture depending on composition.
• Condiments (often suspensions):
  • Ketchup, mustard: suspensions of solid particles (vegetables, seeds) dispersed in an aqueous phase; over time, liquid phase may separate, indicating a suspension.
• Emulsions (a type of colloid):
  • Mayonnaise: an emulsion (colloid) of vegetable oil droplets dispersed in an aqueous vinegar phase, stabilized by emulsifying agents (e.g., egg yolk).
  • Emulsifying agents (e.g., lecithin in egg yolk) help distribute oil droplets evenly in the aqueous phase.
• Other colloids and their general classifications by dispersing medium:
  • Colloids can be classified based on the phase of the dispersing medium:
  • Gaseous dispersing medium: solid aerosols (e.g., cigarette smoke);
  • Liquid dispersing medium: liquids forming emulsions, sols, foams (e.g., milk emulsion, shaving foam);
  • Solid dispersing medium: gels, solid sols (e.g., colored glass).
  • Tyndall effect: colloidal particles scatter light, making a beam of light visible as it passes through the mixture; Brownian motion is the random movement of colloidal particles keeping them suspended.
• Practical examples and applications:
  • Visually distinct mixtures like iced tea with ice (suspension) vs. coffee with milk (colloid).
  • Mayonnaise as a classic emulsion (oil droplets in water with emulsifiers).
  • Condiments as suspensions; emulsions in some sauces.
• Quick reference concept: colloids lie between solutions (uniform, single phase) and suspensions (visible separation); they exhibit unique optical and kinetic properties (Tyndall effect, Brownian motion).

Applications of Separation Methods in Commercial Products

• Separation techniques exploit differences in properties to separate components of mixtures in industry and consumer products.
• In chemical and pharmaceutical industries:
  • Purification of chemicals to acceptable standards; purification of medicines to remove toxic impurities.
  • Paracetamol, aspirin, and other tablets are recrystallized from solution to reach purity; the pure component is then blended with fillers to produce tablets.
• In the petroleum industry:
  • Distillation separates crude oil into fractions (gasoline, kerosene, etc.) based on different boiling points; crude oil is a solution-like mixture of many hydrocarbons.
• Water treatment and purification:
  • Industrial and municipal water often contain particulates; separation methods such as sedimentation, centrifugation, microfiltration, distillation, and activated carbon filtration are used to remove contaminants.
  • Tap water becomes suitable for drinking after removal of particulates, odors, colors, and some bacteria.
• Medical and clinical uses:
  • Centrifugation isolates blood components (plasma, red blood cells, white blood cells) from whole blood; blood is a colloid.
• General takeaway:
  • Separation techniques are essential for product quality, safety, and process efficiency across food, health, cosmetic, petroleum, and other industries.

Key Points

• Homogeneous mixtures (solutions) are mixtures with two or more substances in a uniform, single phase; components are indistinguishable by eye.
• Heterogeneous mixtures have non-uniform composition and can have two or more phases; components are visually distinct and may settle (suspensions) or remain dispersed (colloids).
• Separation techniques exploit differences in properties to separate components in both homogeneous and heterogeneous mixtures.

Check Your Understanding

A. Identify the terms described in each item:

1. It is the mixture that has a constant appearance all throughout. → Homogeneous mixture (solution)
2. It is the mixture whose solute-like particles are dispersed in a medium. → Colloid (dispersed phase in dispersing medium) or more generally a colloidal system.
3. It is the mixture whose solutes are insoluble in the medium, forming layers or clumps that settle when left undisturbed. → Suspension
4. It is a mixture made up of two components: the solute and the solvent. → Solution
5. It is the mixture with components with the largest particle size. → Suspension (largest particles among common mixture types)

B. Classify the given commercial product as a homogeneous mixture or a heterogeneous mixture.

1. iced latte → Heterogeneous
2. milk → Heterogeneous (milk is a colloid, but answer may depend on context; here treated as colloid within heterogeneous classification at the product-level)
3. vodka → Homogeneous (solution of ethanol in water)
4. perfume → Homogeneous (solution of aromatic compounds in a solvent)
5. bronze → Homogeneous (alloy; solid solution)
6. beef noodle soup → Heterogeneous
7. gasoline → Homogeneous (solution of hydrocarbons)
8. steel → Homogeneous (alloy; solid solution)
9. mouthwash → Homogeneous (solution)
10. shampoo → Heterogeneous or Colloid depending on formulation (many shampoos are emulsions/colloids)

C. Complete the table by classifying the given commercial products as solution, suspension, or colloid. Identify the phases.
Mixture Classification Phase Solute (Dispersed Phase) Solvent (Dispersing Medium)

1. mouthwash → Solution Phase: dissolved substances (flavor, antiseptic) Solvent: water
2. shaving foam → Colloid Phase (Dispersed): gas Dispersing Medium: liquid (foam is gas dispersed in liquid/air-laden liquid)
3. brass → Solid solution Phase: Solute (Zn) Solvent: Cu
4. vinegar → Solution Phase: Solute (acetic acid) Solvent: water
5. an unopened bottle of carbonated water → Solution Phase: Solute (CO₂) Solvent: water

D. Challenge Yourself

1. Differentiate black coffee, latte, and iced latte in terms of mixture classification. → Black coffee: solution (coffee solutes dissolved in water); Latte: colloidal suspension (milk droplets dispersed in coffee; can be colloidal depending on conditions); Iced latte: suspension (ice not dissolved, distinct phase) and/or colloid depending on the distribution of milk in the liquid.
2. Differentiate an unopened bottle of soda and an opened bottle of soda in terms of mixture classifications. → Unopened soda: solution with dissolved CO₂ under pressure; opened soda: CO₂ may escape, forming a gas-liquid mixture; as bubbles form, the mixture becomes heterogeneous (gas bubbles present).
3. Why are liquors and wines more expensive compared to beer? → Higher ethanol content and production costs; distillation concentrates ethanol; aging, flavor complexity, and raw materials contribute to price; higher alcohol content generally implies more processing and quality controls.
4. An oil refinery separates the components of crude fossil fuel. How does a refinery help various industries that are dependent on fossil fuel? → Distillation and separation yield specialized fractions (gasoline, kerosene, diesel, etc.) each tailored for specific engines and industrial uses; enables supply of fuels and petrochemical feedstocks across transport, manufacturing, and energy sectors.
5. Explain why purer components present in mixtures entail a greater cost. → Purification processes (distillation, recrystallization, chromatography, etc.) require energy, time, and specialized equipment; achieving higher purity reduces impurities that affect safety and performance, driving up cost but improving product quality and regulatory compliance.

Photo Credits

• Rubbing alcohol bottle image: licensed under Creative Commons Attribution 2.5 Generic.
• IV pole with fluid bags image: licensed under Creative Commons Attribution-Share Alike 3.0 Unported.
• Milli-Q water filtration station image: licensed under CC BY-SA 3.0.

Bibliography

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• Petrucci, Ralph H. General Chemistry: Principles and Modern Applications. Toronto, Ont.: Pearson Canada, 2011.
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