D425 Introduction to Chemistry - Set 4 - Part 1

Correct Answer: Oxidation layer formation

Option b is correct because copper oxidation forms stable patina that seals the surface, preventing deeper corrosion from occurring.
Option a is incorrect because patina is an inorganic copper compound layer, not plastic polymer coating on the metal surface.
Option c is incorrect because patina forms at room temperature through slow oxidation, not through any melting process occurring.
Option d is incorrect because patina is a chemical compound layer, not a magnetic coating applied to the bronze surface.

Correct Answer: Dissolved gas content

Option b is correct because trapped bubbles preserve gas composition and pressure information from the magma source region below.
Option a is incorrect because surface temperature is measured directly; trapped gases reveal deep magma conditions, not surface temperatures present.
Option c is incorrect because gas bubbles create porosity affecting hardness but reveal chemical, not mechanical information about origins.
Option d is incorrect because trapped gases preserve ancient eruption conditions, not weather at the time of collection today.

Correct Answer: Ion exchange process

Option b is correct because fluoride replaces hydroxide in tooth mineral, creating fluorapatite that better resists acid attack.
Option a is incorrect because fluoride treatment affects chemical composition for strength, not surface color or appearance of teeth.
Option c is incorrect because fluoride works through chemical substitution at body temperature, not by heating the tooth surface.
Option d is incorrect because the mechanism is chemical ion exchange, not magnetic attraction between fluoride and tooth enamel.

Correct Answer: Iron in hemoglobin

Option b is correct because iron acts as catalyst for luminol oxidation, producing chemiluminescence that reveals blood traces present.
Option a is incorrect because water alone doesn't catalyze luminol; the iron in blood provides the catalytic activity needed.
Option c is incorrect because white cells aren't the catalyst; iron from red blood cell hemoglobin triggers the reaction.
Option d is incorrect because plasma proteins don't catalyze luminol oxidation; iron from hemoglobin is the active catalyst component.

Correct Answer: Martensite formation

Option b is correct because rapid cooling traps carbon in stressed crystal structure called martensite, creating exceptional hardness achieved.
Option a is incorrect because color change is a visible effect; the hardness comes from internal crystal structure transformation occurring.
Option c is incorrect because quenching prevents oxidation by cooling quickly; rust would actually weaken, not harden the steel.
Option d is incorrect because steel contracts when cooling; hardness comes from crystal structure, not size changes during quenching.

Correct Answer: Antimicrobial action

Option b is correct because sulfur dioxide kills unwanted bacteria and wild yeasts that could spoil wine during storage.
Option a is incorrect because sulfur dioxide can actually bleach color; its role is preservation, not color enhancement in wine.
Option c is incorrect because sulfur dioxide doesn't add sweetness; it's a preservative, not a sugar or sweetening agent.
Option d is incorrect because sulfur dioxide doesn't produce alcohol; it prevents unwanted fermentation by killing microorganisms present naturally.

Correct Answer: Thin film interference

Option b is correct because light waves reflecting from inner and outer surfaces interfere, creating colors dependent on thickness.
Option a is incorrect because colors result from physical light interference, not chemical changes in the soap film itself.
Option c is incorrect because the colors come from visible light interference, not thermal radiation from the bubble film.
Option d is incorrect because soap films aren't magnetic; colors arise from optical interference, not magnetic effects or properties.

Correct Answer: Carbonate scale formation

Option b is correct because lead carbonate scale from hard water creates barrier reducing lead dissolution into drinking water.
Option a is incorrect because lead doesn't form rust like iron; it forms different compounds when reacting with water components.
Option c is incorrect because ancient civilizations didn't gold-plate pipes; natural mineral deposits provided the protective layer formed.
Option d is incorrect because plastics didn't exist in ancient times; mineral scale provided the protective barrier layer naturally.

Correct Answer: Cold light production

Option b is correct because bioluminescence converts chemical energy directly to light without heat waste, achieving near-perfect efficiency levels.
Option a is incorrect because bioluminescence occurs at organism temperature; efficiency comes from avoiding heat production, not increasing temperature.
Option c is incorrect because fireflies use chemical reactions, not electrical current, to produce their characteristic light emission patterns.
Option d is incorrect because bioluminescence involves chemical, not nuclear reactions; it's enzymatic oxidation of luciferin producing light.

Correct Answer: Insufficient decay time

Option b is correct because carbon isotope levels haven't changed measurably in recent centuries, preventing accurate modern dating attempts.
Option a is incorrect because paint thickness doesn't affect carbon dating; the issue is insufficient time for measurable decay.
Option c is incorrect because color is irrelevant to radiocarbon dating; the problem is the short time since painting creation.
Option d is incorrect because frames aren't dated; the issue is that recent organic materials show no measurable isotope changes.

Correct Answer: Carbon dioxide gas

Option b is correct because carbonate reacts with acid producing carbon dioxide, water, and salt, causing gas release experienced.
Option a is incorrect because oxygen isn't produced in acid-carbonate reactions; carbon dioxide is the gas formed during neutralization.
Option c is incorrect because hydrogen gas requires metal-acid reactions; carbonate antacids produce carbon dioxide, not hydrogen gas typically.
Option d is incorrect because nitrogen isn't involved in antacid reactions; carbon dioxide from carbonate decomposition causes the burping.

Correct Answer: Haber-Bosch process

Option b is correct because this process combines nitrogen and hydrogen under pressure with catalysts, producing ammonia industrially scaled.
Option a is incorrect because distillation separates mixtures; it doesn't convert atmospheric nitrogen into useful ammonia compounds for fertilizers.
Option c is incorrect because photosynthesis produces carbohydrates, not ammonia; only certain bacteria naturally fix nitrogen from air.
Option d is incorrect because fermentation produces alcohols and acids, not ammonia from atmospheric nitrogen for fertilizer production purposes.

Correct Answer: Chromium addition

Option b is correct because chromium forms invisible oxide layer that self-heals when damaged, providing continuous corrosion protection throughout.
Option a is incorrect because gold is too expensive for steel production; chromium provides the practical corrosion resistance needed.
Option c is incorrect because carbon is necessary for steel; chromium addition, not carbon removal, provides stainless properties observed.
Option d is incorrect because copper coating would wear off; chromium throughout the alloy provides permanent corrosion resistance achieved.

Correct Answer: Pressure release

Option b is correct because opening reduces pressure, decreasing carbon dioxide solubility and causing rapid gas escape observed immediately.
Option a is incorrect because temperature remains constant when opening; pressure change, not temperature, causes the gas release occurring.
Option c is incorrect because color doesn't affect gas solubility; pressure reduction drives carbon dioxide out of solution rapidly.
Option d is incorrect because sugar doesn't react with carbon dioxide; pressure change causes physical degassing, not chemical reaction.

Correct Answer: Highest reflectivity

Option b is correct because silver reflects more visible light than other metals, creating the brightest mirror surfaces possible.
Option a is incorrect because silver isn't magnetic; its value for mirrors is optical reflectivity, not magnetic properties possessed.
Option c is incorrect because silver is expensive; it's used despite cost because of superior reflective properties, not affordability.
Option d is incorrect because silver is bright metallic, not dark; its high reflectivity makes it ideal for mirrors.

Correct Answer: Magnesium atom

Option b is correct because magnesium in chlorophyll's center allows light absorption and energy transfer for photosynthesis reactions occurring.
Option a is incorrect because iron centers hemoglobin for oxygen transport, not chlorophyll for photosynthesis in plant cells present.
Option c is incorrect because copper appears in some proteins but not chlorophyll; magnesium is the photosynthetic metal center required.
Option d is incorrect because zinc serves other biological functions; magnesium specifically enables chlorophyll's light-harvesting capability in plants.

Correct Answer: Electrolytic reduction

Option b is correct because the Hall-Héroult process uses electricity to extract aluminum from oxide, enabling mass production achieved.
Option a is incorrect because aluminum ore was always available; the challenge was extraction, not mining or finding deposits.
Option c is incorrect because chemical methods couldn't economically reduce aluminum oxide; electrolysis provided the practical solution needed industrially.
Option d is incorrect because aluminum isn't magnetic; the breakthrough was electrolytic reduction, not magnetic separation techniques for processing.

Correct Answer: Lactic acid formation

Option b is correct because bacteria ferment lactose into lactic acid, lowering pH and causing protein coagulation observed visually.
Option a is incorrect because fat oxidation causes rancidity, not the sour taste and curdling from bacterial fermentation primarily occurring.
Option c is incorrect because proteins coagulate due to acid, not destruction; acid formation is the primary spoilage mechanism happening.
Option d is incorrect because water content remains; sourness and thickening result from acid production, not water loss through evaporation.

Correct Answer: Acetyl group transfer

Option b is correct because aspirin transfers its acetyl group to the enzyme, creating permanent modification until replacement occurs.
Option a is incorrect because aspirin is white, not blue; its effectiveness comes from chemical reactivity, not color properties.
Option c is incorrect because aspirin is purely organic without metals; its action involves covalent modification, not metal interactions present.
Option d is incorrect because dissolved aspirin loses crystal structure; the acetyl transfer mechanism, not shape, provides unique action.

Correct Answer: Reversible receptor activation

Option b is correct because tear gas molecules temporarily activate pain receptors but wash away without permanent tissue binding.
Option a is incorrect because permanent bonding would cause lasting damage; tear gas effects are designed to be temporary and reversible.
Option c is incorrect because tear gas compounds are organic without toxic metals; they work through receptor activation, not poisoning.
Option d is incorrect because tear gas isn't radioactive; it works through chemical irritation, not radiation damage to tissues.