SNC2D: Acids, Bases, and the pH Scale

Comprehensive vocabulary flashcards covering the definitions, properties, naming rules, examples, indicators, reactions, and pH scale concepts of acids and bases from the SNC2D lecture notes.

Acid

A group of covalent compounds that contain hydrogen atoms and produce $H^+$ ions when dissolved in water.

Properties of Acids

Characteristics of acids, including tasting sour, acting as electrolytes in aqueous solution, neutralizing bases, and turning litmus paper red.

Ionization of Acids

The process where acid molecules collide with water molecules to form ions, allowing the solution to conduct electricity.

Naming Simple (Binary) Acids

A naming rule consisting of two words: the first word combines the prefix "hydro-", the root of the non-metal element, and the suffix "-ic", followed by the second word "acid".

Hydrochloric Acid ($HCl$)

A binary acid produced by cells in the stomach lining that helps digest food, with stomach digestive fluids having a pH of about 1.5.

Hydrosulfuric Acid ($H_2S$)

A simple binary acid composed of hydrogen and sulfur.

Hydrobromic Acid ($HBr$)

A simple binary acid composed of hydrogen and bromine.

Base

A group of ionic compounds that contain hydroxide ions and produce $OH^-$ ions when dissolved in water.

Properties of Bases

Characteristics of bases, including tasting bitter, feeling slippery, acting as electrolytes in aqueous solution, neutralizing acids, and turning litmus paper blue.

Ammonia ($NH_3$)

A weak base that does not contain hydroxide ions ($OH^-$) in its formula, but acts as a base by accepting $H^+$ ions.

Naming Strong Bases

A rule stating that the name of a base is always the cation name (a metal or polyatomic ion) followed by the word "hydroxide".

Sodium Hydroxide ($NaOH$)

A strong base chemical compound used for making paper and plastic wrap.

Magnesium Hydroxide ($Mg(OH)_2$)

A basic compound commonly used in antacids as heartburn medication.

Calcium Hydroxide ($Ca(OH)_2$)

A base commonly used for controlling soil and water pH.

Ammonium Hydroxide ($NH_4OH$)

A base compound commonly found in window cleaners such as Windex.

pH Scale

A numerical measure ranging from 0 to 14 that determines how acidic or basic (alkaline) a solution is.

pH

An expression standing for "Potential Hydrogen" that measures the concentration of hydrogen ions ($H^+$) in a solution.

Neutral Solution

A solution that has a pH of exactly 7, exemplified by pure water.

Acidic Solution (pH Scale)

A solution with a pH lower than 7, where a lower pH indicates a higher concentration of hydrogen ions ($H^+$) and a stronger acid.

Basic Solution (pH Scale)

A solution with a pH higher than 7, where a higher pH indicates a lower concentration of $H^+$ ions, a higher concentration of $OH^-$ ions, and a stronger base.

Indicator

A substance that changes colour depending on the pH of the solution it is placed in.

Litmus Paper

A pH indicator that displays a red colour in acidic solutions and a blue colour in basic solutions.

Phenolphthalein

A pH indicator that remains colourless in acidic solutions and turns pink in basic solutions.

Bromothymol Blue

A pH indicator that turns yellow in an acid and blue in a base.

Methyl Orange

A pH indicator that appears red in an acid and yellow in a base.

Phenol Red

A pH indicator that turns yellow in an acid and pink in a base.

Neutralization Reaction

A special type of double displacement reaction where an acid and a base react to produce water ($H_2O$) and a salt (ionic compound), bringing the resulting pH closer to 7.

Heartburn (Gastroesophageal Reflux)

A condition caused by overeating or spicy foods where stomach acid leaks upward out of the stomach and into the esophagus.

Antacid

A basic medication, such as $Al(OH)_3$ or $Mg(OH)_2$, used as a short-term fix to neutralize excess stomach acid.

Hydroxide Ion ($OH^-$)

The polyatomic ion that most commonly appears in the chemical formulas of bases.

Baking Soda

A common household basic substance frequently used in baking.

Bleach

A common household cleaning substance that serves as an example of a strong base.

Vinegar

A common household acidic substance found in salad dressings.