Acids and Chemical Reactions Review

Comprehensive vocabulary flashcards covering acid-base definitions, properties, reaction types, indicators, energy changes, and equation balancing.

Acid (Arrhenius definition)

A substance that releases hydrogen ions ($H^+$) when dissolved in water, where more $H^+$ produces a lower pH and a stronger effect.

SPECS

A memory acronym for acid properties: Sour taste (e.g., lemon, vinegar), PH below $7$ (each step down is ten times more acidic), Electricity (conducts because ions move), Corrosive (eats metals, stone, and skin), and Seeing red (turns blue litmus paper red).

pH Scale

A scale spanning from $0$ (acid) to $14$ (base) with $7$ being neutral, including stomach acid ($\text{pH } 1.5\text{ to }3.5$), lemon juice ($\text{pH } 2$), vinegar and soda ($\text{pH } 3$), pure water ($\text{pH } 7$), baking soda ($\text{pH } 9$), and bleach ($\text{pH } 13$).

Strong Acid

An acid that splits completely into ions ($95\text{-}100\%$ dissociation) in water; the three primary examples to know are hydrochloric acid ($HCl$), sulfuric acid ($H_2SO_4$), and nitric acid ($HNO_3$).

Weak Acid

An acid that splits only partly into ions ($<5\%$ dissociation), such as the acids in vinegar, citrus, and soda, where the reaction runs both ways.

Acid Strength vs. Concentration

The distinction that 'strong' and 'weak' describe how much an acid ionizes (degree of dissociation), not how concentrated it is.

Acid Dilution Safety Rule

A safety protocol stating to add acid to water, never water to acid, and wear goggles, because strong acids burn on contact.

Litmus Paper Test

An indicator test where blue litmus paper turns red in an acid and stays blue in neutral or base, while red litmus paper stays red in acid or neutral and turns blue in a base.

Base (Arrhenius definition)

A substance that produces hydroxide ions ($OH^-$) when dissolved in water.

Properties of Bases

General characteristics including a bitter taste, a slippery feel like soap, and the ability to be caustic and burn skin.

Degree of Dissociation

The extent to which an electrolyte ionizes in water, categorized as strong electrolytes ($95\text{-}100\%$ dissociation) or weak electrolytes ($<5\%$ dissociation).

Acid + Metal Reaction

A reaction producing a salt and hydrogen gas ($H_2$), verified by bubbles and a lit splint giving a squeaky pop (e.g., $Zn + 2HCl \rightarrow ZnCl_2 + H_2$).

Acid + Carbonate Reaction

A reaction producing a salt, water, and carbon dioxide ($CO_2$), verified by fizzing that turns limewater cloudy (e.g., $CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2$).

Neutralization Reaction

An acid + base reaction producing a salt and water, verified by the flask warming and pH moving toward $7$ (e.g., $HCl + NaOH \rightarrow NaCl + H_2O$).

Salt Naming Convention

The system of naming a salt by taking the metal's name and appending the acid's ending: $HCl$ gives a chloride, $H_2SO_4$ gives a sulfate, and $HNO_3$ gives a nitrate (e.g., magnesium + sulfuric acid yields magnesium sulfate).

Synthesis Reaction

A reaction cued by 'Join' where many reactants combine to form one product following the pattern $A + B \rightarrow AB$ (e.g., $2H_2 + O_2 \rightarrow 2H_2O$; real-world example: rusting).

Decomposition Reaction

A reaction cued by 'Split' where one reactant breaks down into multiple products following the pattern $AB \rightarrow A + B$ (e.g., $2H_2O_2 \rightarrow 2H_2O + O_2$; real-world example: peroxide fizzing on a cut).

Single Replacement Reaction

A reaction cued by 'Kick-out' where a lone element swaps into a compound following the pattern $A + BC \rightarrow AC + B$ (e.g., $Zn + 2HCl \rightarrow ZnCl_2 + H_2$; real-world example: metal dissolving in acid).

Double Replacement Reaction

A reaction cued by 'Partner swap' where two compounds trade partners following the pattern $AB + CD \rightarrow AD + CB$ (e.g., $HCl + NaOH \rightarrow NaCl + H_2O$; real-world example: antacids).

Combustion Reaction

A reaction cued by 'Burn' where a fuel reacts with oxygen to produce carbon dioxide and water following the pattern $\text{Fuel} + O_2 \rightarrow CO_2 + H_2O$ (e.g., $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$; real-world example: gas stoves, engines).

Synthesis vs. Combustion Distinction ($2Mg + O_2 \rightarrow 2MgO$)

The reaction $2Mg + O_2 \rightarrow 2MgO$ is synthesis rather than combustion because no $CO_2 + H_2O$ is produced, even though many textbooks refer to it as burning.

Exothermic Reaction

A reaction where heat exits to the surroundings (e.g., combustion, hand warmers).

Endothermic Reaction

A reaction where heat enters from the surroundings (e.g., cold packs, photosynthesis).

Signs of a Chemical Reaction

Observable evidence of a reaction: gas bubbles, a color change, a solid forming (a precipitate), a temperature change, light, or odor.

Balancing Order of Priority

The rule for ensuring equal numbers of each atom on both sides: balance metals first, then other elements, leaving $H$ and $O$ for last.