foundations chapter 6 chemistry and chemical safety

Chemistry

the science that deals with the composition, structures, and properties of matter and how matter changes under different conditions

Matter

any substance that occupies space and has mass (weight)

Element

simplest form of chemical matter and contains only one type of atom

Atoms

the basic unit of matter, weigh a nucleus at the center surrounded by negatively charged electrons that move around the nucleus in orbits

Molecule

a chemical combination of two or more atoms in definite (fixed) proportions

Elemental Molecule

a molecule containing two or more atoms of the same element in definite (fixed) proportions

Compound Molecule

chemical combinations of two or more atoms of different elements in definite (fixed) proportions; also known as compounds

Physical Change

a change in the form of physical properties of a substance, without a chemical reaction or the creation of a new substance; ex. boiling point, color, density, hardness, ice melting, odor, solubility, temporary hair color, weight

Chemical Change

a change in the chemical composition or makeup of a substance; ex. burning wood, hair lightening, permanent hair color, rusting iron

Physical Properties

characteristics that can be determined without a chemical reaction and do not involve a chemical change in the substance

Chemical Properties

characteristics that can be determined only by a chemical reaction and involve a chemical change in the substance

Pure Substance

a chemical combination of matter in definite (fixed) proportions

Physical Mixture

a physical combination of matter in any proportion

Solution

a stable, uniform mixture of two or more substances; where one substance completely dissolves into another; ex. coffee & sugar → sugar completely dissolves into the coffee

Solute

substance that is dissolved in a solution

Solvent

substance that dissolves the solute and makes the solution

Miscible

liquids are mutually soluble, meaning that they can be mixed together to form solutions; ex. water and alcohol → when they are mixed together, they stay mixed

Immiscible

liquids are not capable of being mixed together to form stable solutions; water and oil → they can be mixed together but will separate when they are left sitting still

Suspensions

unstable physical mixtures of undissolved particles in a liquid; a mixture where particles spread throughout a liquid but dont dissolve; ex. orange juice with pulp → pieces of pulp are suspended in the juice and settle

Emulsion

an unstable physical mixture of two or more immiscible substances plus a special ingredient called an emulsifier; mixture of two liquids that normally dont mix together; ex. mayo → oil and water based ingredients are combined and held together by emulsifiers

Emulsifier

an ingredient that brings two normally incompatible materials together and binds them into a uniform and fairly stable mixture

Surfactants

substances that allow oil and water to mix, or emulsify

Oil-in-Water (O/W) Emulsion

oil droplets are emulsified in water; ex. milk, facial cleanser

Water-in-Oil (W/O) Emulsion

water droplets are emulsified in oil; ex. styling creams, cold creams, suntan lotions, and foot balms

Overexposure

refers to how prolonged, repeated, or long-term exposure to certain product ingredients can cause sensitivity in some people

pH (Potential Hydrogen)

the term represents the quantity of hydrogen ions; p represents quantity; h represents the hydrogen ions

Ion

an atom or molecule that carries an electrical charge

Ionization

the separation of an atom or molecule into positive and negative ions

Anion

an ion with a negative electrical charge; aNIon → negative

Cation

an ion with a positive electrical charge; caTion → positive

pH Scale

used to measure the acidity and alkalinity of substances; range 0-14; below 7 = acidic, 7 = neutral, above 7 = alkaline (base)

Alpha Hydroxy Acids (AHAs)

derived mostly from milk or fruit sugars, are examples of acids often used to exfoliate the skin and to help adjust the pH of a lotion, conditioner, or cream;

Glycolic Acid

an alpha hydroxy acid used in exfoliation and to lower pH of products

Alkalis

owe their chemical reactivity to the hydroxide ion; also known as bases

Sodium Hydroxide

a very strong alkali used in chemical hair relaxers, callous softeners, and drain cleaners; commonly known as lye

Acid-Alkali Neutralization Reactions

occur when an acid is mixed with an alkali in equal proportions, balancing the total pH and forming water and a salt; restores the natural pH

Oxidation-Reduction (Redox)

a chemical reaction in which oxidation and reduction take place at the same time; oxidation loses hydrogen, reduction gains hydrogen

Exothermic Reaction

when certain chemical reactions release energy in the form of heat

Combustion

the rapid oxidation of a substance accompanied by the production of heat and light

Endothermic Reaction

a chemical reaction that requires the absorption of energy or heat from an external source for the reaction to actually occur

Acidic Solution

a pH below 7

Alkaline Solution

a pH above 7

Oxidizing Agent

a substance that releases oxygen

Reducing Agent

a substance that add hydrogen to a chemical compound or subtracts oxygen from the compound

Incompatible

substances that should not be mixed or even stored near each other

Safety Data Sheet (SDS)

include safety information about products compiled by the manufacturer; required by OSHA

Carcinogen

a substance that causes or is believed to cause cancer

Mutagen

a substance that may cause cancer but not always

Combustible

material capable of igniting and burning

Flammable

material that is easier to ingite