Calling all aspiring stylists! Ready to power up your knowledge of cosmetology chemistry and electricity? This free quiz is designed to challenge your understanding of milady ch 12 concepts, from molecular structures to current flow. Dive into a fun cosmetology chemistry test and explore practical questions similar to those in chapter 12 basics of chemistry cosmetology answers and chapter 12 milady workbook answers. Plus, compare your results with peers on cosmetology proprofs. Whether you're prepping for board exams, brushing up on key theory, or exploring a cosmetology electricity quiz for the first time, you'll sharpen your skills and build confidence. Test your expertise now and master the essentials in minutes!
What is the basic unit of matter?
Atom
Molecule
Electron
Compound
An atom is the smallest unit of an element that retains its chemical properties. Atoms are composed of protons, neutrons, and electrons. Molecules and compounds are made when atoms bond together. For more information see Atom - Wikipedia.
What is the range of the pH scale?
0 to 14
1 to 10
0 to 7
7 to 14
The pH scale ranges from 0 (most acidic) to 14 (most alkaline), with 7 being neutral. It measures hydrogen ion concentration in a solution. Salons and cosmetologists use pH to understand product interactions with hair and skin. Learn more at pH - Wikipedia.
Which of the following describes a homogeneous mixture of two or more substances?
Solution
Suspension
Emulsion
Colloid
A solution is a homogeneous mixture where the solute is uniformly distributed in the solvent. In cosmetology, solutions include liquid styling products and hair color developers. Suspensions and colloids differ because their particles do not dissolve completely. See Solution (chemistry) - Wikipedia.
An emulsion is a type of mixture composed of two immiscible liquids stabilized by:
Emulsifier
Acid
Alkali
Buffer
An emulsifier is a surfactant that stabilizes emulsions by reducing surface tension between oil and water phases. Common emulsifiers in cosmetology include lecithin and stearic acid. They help create smooth creams and lotions. For more detail see Emulsifier - Wikipedia.
Which part of an atom has no electrical charge?
Neutron
Proton
Electron
Nucleus
Neutrons carry no electric charge and reside in the atomic nucleus along with protons. Protons are positively charged while electrons are negatively charged. The balance of these charges determines the atom's overall charge. Learn more at Neutron - Wikipedia.
Which substance is a good conductor of electricity?
Copper
Rubber
Glass
Plastic
Copper is a metal known for its high electrical conductivity and is often used in wiring. Insulators like rubber, glass, and plastic resist electrical flow. Conductors allow current to pass through them easily. See Copper - Wikipedia.
How many electrons can the second shell of an atom hold at maximum?
8
2
16
18
The second electron shell (the L shell) can hold up to 8 electrons following the 2n˛ rule. The first shell holds 2 electrons and subsequent shells hold more. Electron configuration determines chemical reactivity. More info at Electron shell - Wikipedia.
What type of reaction occurs when natural hair pigment is lightened during bleaching?
Oxidation
Reduction
Neutralization
Hydrolysis
Bleaching hair involves oxidation, where hydrogen peroxide reacts with melanin and removes pigment. The process breaks down melanin molecules by adding oxygen. Reduction is the gain of electrons, which is not the primary mechanism in bleaching. For more details see Hair bleaching - Wikipedia.
An ion with a positive electrical charge is called a:
Cation
Anion
Radical
Isotope
A cation is an ion that has lost one or more electrons, resulting in a net positive charge. Anions carry a negative charge, having gained electrons. Cations and anions are both essential in chemical reactions and electrotherapy. See Ion - Wikipedia.
Which substance speeds up a chemical reaction without being consumed?
Catalyst
Solvent
Solute
Emulsifier
Catalysts lower the activation energy required for reactions, increasing the reaction rate without undergoing permanent change. Enzymes are biological catalysts. In cosmetology, catalysts can be found in some color developer formulas. Learn more at Catalysis - Wikipedia.
What is the pH of pure water at room temperature?
7
0
14
3
Pure water has a neutral pH of 7, indicating equal concentrations of hydrogen and hydroxide ions. Temperature can slightly affect pH, but it remains close to 7 at 25°C. Cosmetologists use this knowledge when formulating gentle products. More at Water - Wikipedia.
The mass number of an element equals the sum of:
Protons and neutrons
Protons and electrons
Neutrons and electrons
All three subatomic particles
Mass number is the total count of protons and neutrons in an atom's nucleus. Electrons have negligible mass and are not included. This concept helps distinguish isotopes. See Isotope - Wikipedia.
Which unit measures electric current?
Ampere
Volt
Ohm
Watt
The ampere (A) is the SI unit of electric current. Volts measure potential difference, ohms measure resistance, and watts measure power. Understanding these units is fundamental for safely using electrical devices. More at Ampere - Wikipedia.
What is the primary role of an emulsifier in a cosmetic emulsion?
Stabilize the oil-water mixture
Adjust pH
Provide color
Increase viscosity
Emulsifiers use their hydrophilic and lipophilic ends to bind water and oil phases, preventing separation. They create stable creams and lotions. Without emulsifiers, most cosmetic formulations would separate. See Emulsion - Wikipedia.
Which of the following is considered an acidic solution?
Lemon juice
Baking soda solution
Ammonia solution
Bleach
Lemon juice has a low pH (around 2), making it acidic. Baking soda and ammonia solutions are alkaline, and bleach is strongly alkaline. Cosmetologists must know pH to prevent skin and hair damage. Learn more at Acid - Wikipedia.
Which type of mixture separates upon standing and requires shaking before use?
Suspension
Solution
Emulsion
Colloid
A suspension contains larger particles that will settle out over time unless agitated. Cosmetics like certain pigments or toners can be suspensions. Solutions and colloids remain uniformly mixed without shaking. For more details see Suspension (chemistry) - Wikipedia.
Which instrument is commonly used to measure pH in salon solutions?
pH meter
Refractometer
Titrator
Spectrophotometer
A pH meter uses a glass electrode to measure hydrogen ion concentration in solutions. It provides a digital pH readout. Refractometers measure refractive index rather than acidity. Learn more at pH meter - Wikipedia.
What is the function of a buffer solution?
Resist changes in pH
Catalyze reactions
Increase solubility
Sterilize products
Buffer solutions contain a weak acid and its conjugate base to minimize pH fluctuations when acids or bases are added. They are important in stabilizing cosmetic formulations. They do not catalyze or sterilize. More at Buffer solution - Wikipedia.
Why is distilled water a poor conductor of electricity?
Lacks ions
High pH
Contains impurities
High temperature
Distilled water has had minerals and ions removed, which are required to carry electrical current. Pure water has extremely low conductivity. Adding salts or electrolytes increases conductivity. See Distilled water - Wikipedia.
Which type of electrical current changes direction periodically?
Alternating current
Direct current
Static current
Galvanic current
Alternating current (AC) periodically reverses direction and is commonly used in high-frequency devices like Tesla. Direct current (DC) flows in one direction only. Static current is built-up charge that does not flow continuously. For more see Alternating current - Wikipedia.
Which current is primarily used for ionic penetration (iontophoresis) in cosmetology?
Galvanic current
Tesla current
Alternating current
Static current
Galvanic current is a direct current used to drive water-soluble products into the skin. It can be positive (desincrustation) or negative (iontophoresis). Tesla current is alternating and not used for penetration. See Iontophoresis - Wikipedia.
What is the SI unit of electrical resistance?
Ohm
Volt
Ampere
Watt
The ohm (?) is the SI unit of electrical resistance, representing the resistance between two points where one volt applied produces one ampere of current. Volts, amperes, and watts measure other electrical properties. Learn more at Ohm - Wikipedia.
What happens to current if voltage increases while resistance remains constant?
Current increases
Current decreases
No change
Resistance increases
According to Ohm’s law (V = IR), if resistance (R) is constant, an increase in voltage (V) results in a proportional increase in current (I). This principle is used in electrical device design. See Ohm's law - Wikipedia.
A mole in chemistry is a unit measuring:
Amount of substance
Mass
Volume
Energy
A mole is the SI unit for the amount of substance, defined as exactly 6.022×10^23 elementary entities (Avogadro’s number). It allows chemists to relate macroscopic quantities to number of molecules or atoms. More at Mole (unit) - Wikipedia.
Avogadro’s number describes the number of particles in one mole. What is its approximate value?
6.02×10^23
3.00×10^8
1.60×10^-19
9.81
Avogadro’s number (approximately 6.022×10^23) is the number of atoms or molecules in one mole of substance. It bridges micro-scale particles to macroscopic mass. The other values correspond to speed of light, electron charge, and gravitational acceleration. See Avogadro constant - Wikipedia.
Surfactants in shampoos primarily function to:
Lower surface tension
Adjust pH
Prevent oxidation
Increase viscosity
Surfactants reduce surface tension between water and oil, allowing dirt and oil to be emulsified and washed away. They are key cleansing agents in shampoos and soaps. They do not typically adjust pH or prevent oxidation. More info at Surfactant - Wikipedia.
Which of these solutions has the same solute concentration as a cell, causing no net movement of water?
Isotonic
Hypotonic
Hypertonic
Buffered
Isotonic solutions have equal solute concentration to that of cells, leading to equilibrium in water movement. Hypotonic solutions cause cells to swell, while hypertonic cause them to shrink. Buffered relates to pH stability. See Tonicity - Wikipedia.
Which element is most abundant in the keratin of human hair?
Sulfur
Oxygen
Hydrogen
Nitrogen
Keratin is rich in cysteine amino acids, which contain sulfur. Sulfur-sulfur (disulfide) bonds contribute to hair strength and structure. Other elements are present but not as abundant in structural bonding. Learn more at Keratin - Wikipedia.
Activation energy in a chemical reaction refers to:
Minimum energy needed to start the reaction
Energy released by the reaction
Total energy change
Energy stored in bonds
Activation energy is the threshold energy required for reactants to form the transition state and proceed to products. Catalysts work by lowering activation energy. Energy released is termed exothermic output. See Activation energy - Wikipedia.
Which dispersion has particle sizes between those of true solutions and suspensions and does not settle out?
Colloid
Solution
Suspension
Emulsion
Colloids have particle sizes from 1 to 1000 nanometers that remain dispersed and do not settle. Emulsions are a type of colloid of two immiscible liquids. Suspensions have larger particles that eventually settle. More at Colloid - Wikipedia.
What does zeta potential measure in colloidal systems?
Surface charge of particles
Particle size
Viscosity
pH level
Zeta potential quantifies the electric potential at the slipping plane around colloidal particles, indicating stability. Higher absolute zeta potential values mean particles repel each other more, preventing aggregation. This is important for stable emulsions in cosmetics. See Zeta potential - Wikipedia.
At approximately what pH is the isoelectric point of human hair protein?
3.67
7.00
5.50
9.50
The isoelectric point is where the protein net charge is zero. For keratin in hair, this occurs around pH 3.67. At this pH, hair is most prone to damage due to reduced charge repulsion. Learn more at Protein Isoelectric Point - NCBI.
Which type of chemical bond in hair protein provides most of its strength?
Disulfide bonds
Hydrogen bonds
Peptide bonds
Ionic bonds
Disulfide bonds form between cysteine residues in keratin and confer rigidity and strength. Hydrogen bonds are weaker and can break with water. Peptide bonds link amino acids in the backbone. For more see Disulfide bond - Wikipedia.
Faraday’s first law of electrolysis states that the mass of a substance deposited is directly proportional to:
Quantity of electric charge passed
Voltage applied
Time of electrolysis
Resistance of solution
Faraday’s first law indicates mass deposited (or liberated) at an electrode is proportional to the total charge passed. It does not directly depend on voltage, time, or resistance, though these affect charge. See Faraday's laws of electrolysis - Wikipedia.
How many coulombs are equivalent to one ampere-second?
1
0.5
2
10
One coulomb is defined as the amount of charge transferred by a constant current of one ampere in one second (1 A·s = 1 C). This relationship is fundamental in electrical calculations. For more see Coulomb - Wikipedia.
Which law defines the relationship V=IR?
Ohm’s law
Faraday’s law
Kirchhoff’s law
Coulomb’s law
Ohm’s law states that voltage (V) across a conductor is directly proportional to current (I) times resistance (R). It is a foundational principle in electricity. Other laws describe different electrical relationships. See Ohm's law - Wikipedia.
How is electrical power calculated in a circuit?
P=V×I
P=I^2×R
P=V/R
P=V+I
Electrical power (P) in watts is calculated by multiplying voltage (V) by current (I). The formula P=I˛R also works but is derived by substituting Ohm’s law. P=V+I is incorrect since power is a product, not a sum. More at Electrical power - Wikipedia.
What does the Nernst equation relate in electrochemistry?
Electrode potential and ion concentration
Current and voltage
Resistance and temperature
pH and pKa
The Nernst equation calculates the electrode potential under non-standard conditions based on ion concentrations. It is key in understanding redox reactions and electrolysis. It does not directly relate current or pH parameters. See Nernst equation - Wikipedia.
Which device is used to step up or step down voltage in electrical circuits?
Transformer
Rectifier
Capacitor
Inductor
A transformer transfers electrical energy between circuits through electromagnetic induction, changing voltage levels. Rectifiers convert AC to DC. Capacitors and inductors store energy rather than changing voltage. More at Transformer - Wikipedia.
What safety device interrupts excess current to prevent circuit damage?
Fuse
Resistor
Switch
Capacitor
A fuse melts when current exceeds a safe limit, breaking the circuit and preventing overheating. Resistors limit current but do not interrupt flow. Switches manually open or close circuits. See Fuse - Wikipedia.
Why does distilled water have minimal electrical conductivity?
Absence of ions
High purity
Neutral pH
Low temperature
Distilled water lacks dissolved salts and minerals, which are sources of ions that carry electrical current. Neutral pH is unrelated to conductivity. Purity describes absence of contaminants. More at Distilled water - Wikipedia.
Which bond type in hair is disrupted by heat or moisture and reforms when conditions normalize?
Hydrogen bonds
Disulfide bonds
Peptide bonds
Ionic bonds
Hydrogen bonds in hair are weak and break under heat or moisture, allowing hair to be reshaped. They reform when the hair cools or dries. Disulfide bonds require chemical processes to break. See Hair - Wikipedia.
According to the Nernst equation, electrode potential depends on:
Ion concentration and temperature
Current and resistance
pH and molarity
Voltage and capacitance
The Nernst equation E = E° - (RT/nF) lnQ shows that electrode potential depends on temperature, ion concentration, and reaction quotient. It does not directly involve resistance or capacitance. This is critical in advanced electrochemistry. See Nernst equation - Wikipedia.
High-frequency (Tesla) current used in cosmetology typically operates in which frequency range?
100 kHz to 250 kHz
50 Hz to 60 Hz
1 kHz to 5 kHz
1 MHz to 5 MHz
Tesla high-frequency devices operate at radio frequencies around 100 to 250 kHz to produce safe thermal effects. Lower frequencies are used in household AC. Higher MHz ranges are beyond typical cosmetic applications. Learn more at High frequency - Wikipedia.
In iontophoresis, enhancing skin permeability often involves which mechanism?
Electrorepulsion of like-charged molecules
Thermal heating
Ultraviolet radiation
Ultrasonic cavitation
Iontophoresis uses electrorepulsion to drive like-charged drug or cosmetic molecules into the skin. It does not rely on heat, UV, or ultrasound. This improves penetration of active ingredients. See Iontophoresis - Wikipedia.
What is the maximum safe galvanic current typically used for facial treatments?
3 to 4 mA
10 to 12 mA
0.1 to 0.5 mA
20 to 30 mA
In cosmetology, galvanic facial treatments use currents generally between 3 and 4 milliamperes for safety and efficacy. Higher currents risk skin irritation or burns. Currents below 1 mA are often too weak for penetration. See Galvanic skin treatments - NCBI.
At what pH does the hair cuticle begin to lift, facilitating color or chemical treatments?
Above 7.0
Below 4.5
Exactly 7.0
Above 10.0
Hair cuticles lift in alkaline conditions (above pH 7), allowing color or chemical agents to penetrate. Acids below pH 4.5 cause cuticles to contract. A neutral pH (7) maintains cuticle flatness. More at Hair damage - Wikipedia.
Total dissolved solids (TDS) in water most directly affect which property relevant to electrotherapy?
Conductivity
pH
Viscosity
Temperature
TDS measures the concentration of ions in water, which directly increases its electrical conductivity. Higher TDS yields better current flow in electrotherapy. pH, viscosity, and temperature are separate properties. Learn more at Total dissolved solids - Wikipedia.
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Study Outcomes
Understand core cosmetology chemistry concepts -
Gain a solid grasp of basic chemistry principles, including atom structure, pH balance, and chemical reactions used in salon services.
Identify components of emulsions -
Recognize and differentiate the roles of oil-in-water and water-in-oil emulsions for effective product formulation and stability.
Apply electrical principles safely -
Learn to operate electrical salon equipment correctly by understanding current, voltage, and safety protocols in cosmetology.
Recall Milady Ch 12 and workbook answers -
Review key terms and solutions from Milady chapter 12 and chapter 12 milady workbook answers to reinforce your theoretical knowledge.
Analyze quiz scenarios on cosmetology ProProfs -
Use real-world examples and scored feedback to sharpen your test-taking strategies for cosmetology proprofs quizzes.
Evaluate knowledge gaps -
Compare your results against chapter 12 basics of chemistry cosmetology answers to pinpoint strengths and areas for further review.
Cheat Sheet
pH Scale Fundamentals -
Understanding pH is crucial for cosmetology chemistry; it's a logarithmic scale defined by pH = - log[H+], so each unit change reflects a tenfold shift in hydrogen ion concentration (American Chemical Society). For example, a shampoo with pH 5.5 is slightly acidic, matching skin's natural pH to seal cuticles and prevent dryness. Mnemonic tip: "Low pH, More H" helps you remember that lower values mean higher acidity.
Emulsion Types -
Emulsions are mixtures of two immiscible liquids: oil-in-water (O/W) or water-in-oil (W/O), often stabilized by emulsifying agents like cetyl alcohol (Milady, Chapter 12). Oil-in-water emulsions feel lighter and are used in lotions, whereas water-in-oil are richer, found in cold creams. Think "O/W = Ordinary Water" to recall oil droplets dispersed in water for everyday lotions.
Surfactants and Cleansing Action -
Surfactants have hydrophilic heads and lipophilic tails that reduce surface tension, enabling oil and dirt to wash away (Journal of Cosmetic Science). Common examples include sodium lauryl sulfate and cocamidopropyl betaine in cleansers. A quick trick: "Water hates oil, so grab a surfactant coil!" reminds you surfactants bridge the two.
Oxidation - Reduction in Hair Coloring -
Oxidation - reduction (redox) reactions alter hair pigment by adding or removing electrons; hydrogen peroxide oxidizes natural melanin before dye molecules penetrate (NIOSH). For instance, permanent color uses an alkaline agent to swell the cuticle and allow oxidizers to lighten and then deposit new color. Remember "OIL RIG": Oxidation Is Loss, Reduction Is Gain (of electrons).
Electrical Concepts in Salon Tools -
Salon devices use either direct current (DC) or alternating current (AC), and knowing conductors (metals) versus insulators (rubber) ensures safe handling (OSHA). Galvanic current, a form of DC, drives solutions into the skin during facials, while Faradic current (pulsed AC) tones muscles. A simple phrase, "Conductors carry current, insulators isolate it," helps keep safety top of mind.
