Science 30 - Unit B: Chemistry and the Environment (Chapter 1: Acid Deposition)

Vocabulary practice flashcards covering atmospheric emissions, acid-base chemistry, titrations, soil leaching, biomagnification, and acid deposition from Science 30 Unit B: Chemistry and the Environment.

Claus Process

A two-step industrial process used to remove hydrogen sulfide ($H_2S(g)$) from sour natural gas to recover elemental sulfur.

Thermal Step of the Claus Process

The initial step of the Claus process that takes place in a furnace at high temperatures, where hydrogen sulfide reacts with oxygen to form sulfur and sulfur dioxide ($SO_2(g)$).

Catalytic Step of the Claus Process

The second step of the Claus process where hydrogen sulfide reacts with sulfur dioxide to yield solid sulfur and water vapor according to $H_2S(g) + SO_2(g) \rightarrow S(s) + H_2O(g)$.

Sour Gas

Natural gas that contains hydrogen sulfide ($H_2S(g)$), requiring sulfur-reduction technologies before use.

$SO_2$ Emissions in Canada (2000)

Total sulfur dioxide emissions estimated at $2.4 \times 10^6\,\text{t}$ (tonnes) in Canada in the year 2000, originating primarily from industrial sources (68%) and electric utilities (27%).

SMOG FREE Program

A voluntary vehicle emissions-testing program operating in Calgary from March to May 1993, standing for 'Save Money On Gas From Reduced Exhaust Emissions,' which offered free vehicle inspections and discount coupons.

Wet Deposition

A form of acid deposition in which acidic substances and airborne emissions return to Earth's surface incorporated into precipitation such as rain, snow, or fog.

Dry Deposition

A form of acid deposition in which airborne acidic particles and gases settle directly onto surfaces without precipitation.

Hydronium Ion ($H_3O^+$)

The positively charged ion produced when acids react with water, whose concentration directly determines the pH of an aqueous solution.

pH Scale

A scale that relates quantitatively to the concentration of hydronium ions ($H_3O^+$) within an aqueous solution to measure its acidity or basicity.

Antacid

A basic compound, such as calcium carbonate ($CaCO_3(s)$) or aluminium hydroxide ($Al(OH)_3(s)$), taken to relieve heartburn by neutralizing excess aqueous hydronium ions in stomach acid.

Buffering Capacity

The capability of soil, water, or bedrock containing specific mineral compounds (such as carbonates) to resist changes in pH when exposed to acid deposition.

Leaching

The environmental process in which hydronium ions in acidic deposition react with soil minerals (such as $Al(OH)_3(s)$), dissolving and mobilizing metal ions into groundwater, streams, and lakes.

Biomagnification

The progressive increase in the concentration of a persistent substance (such as mercury) in the tissues of organisms across successive trophic levels of a food chain.

Titration

A laboratory analytical technique where a measured volume of a standard solution is dispensed from a burette to react completely with a specific volume of an unknown solution in an Erlenmeyer flask.

Standard Solution

A solution of precisely known concentration used in titration experiments to neutralize and determine the concentration of an unknown solution.

Burette

A calibrated piece of laboratory glassware equipped with a stopcock, used in titrations to dispense accurately measured volumes of a standard solution.

Erlenmeyer Flask

A conical laboratory container with a flat base and narrow neck used to hold and swirl the sample solution during a titration.

Endpoint

The observable point in a titration where an indicator undergoes a permanent colour change (such as turning light pink with phenolphthalein), signaling that the reaction is complete.

Indicator

A chemical substance that changes colour over a characteristic pH range (such as phenolphthalein, thymol blue, or bromocresol green) to signal the endpoint of a titration or estimate solution pH.

Photochemical Smog

A hazardous type of air pollution formed when airborne pollutants like nitrogen oxides ($NO_x$) and volatile substances react in the atmosphere under specific sunlight and weather conditions.

$$NO_x$$

A collective formula representing oxides of nitrogen produced during high-temperature combustion processes (such as in automobile engines) that contribute significantly to wet and dry acid deposition.

Soil Acidification Ratios ($[Ca^{2+}]:[Al^{3+}]$)

The concentration ratio of calcium ions to aluminium ions measured in soil under acid rain exposure, progressing from $1:1$ prior to acidification, to $2:1$ during early stress, and down to $0.2:1$ under severe acidification.

Relative Solubility of Combustion Oxides

The chemical property whereby carbon dioxide is only slightly soluble in water, limiting its contribution to acid deposition, while oxides of sulfur and nitrogen are considerably more soluble in water and drive the acidification of precipitation.