G3 Science (Chemistry) Maintaining Air Quality · question set

Try K326/K328 environmental exam-style questions. Covers clean-air composition, prescribed pollutant sources and effects, acid rain, the carbon cycle, carbon dioxide and methane, infrared heat trapping and global-warming effects. Emission controls and ozone depletion are excluded.

SEC G3 Combined Science Chemistry component 2027

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A second instrument measures the same location without drying the air and includes 2.0% water vapour. Why can its nitrogen percentage be lower?

Measured composition of dried air sample A
Gas	Percentage by volume (%)
Nitrogen	78.0
Oxygen	20.9
Argon	0.9
Carbon dioxide	0.04

Water vapour changes the stated total, so nitrogen can be a smaller percentage without being removed
Nitrogen reacts completely with water vapour
Dry air contains exactly 2.0% water vapour
Oxygen replaces nitrogen whenever humidity rises

Unburned hydrocarbon vapour is measured beside a damaged fuel-storage valve. Which proposed action targets the measured release?

Isolate the system safely and repair or replace the leaking valve
Open the valve wider so the vapour disperses faster
Capture methane at an unrelated landfill
Increase the oxygen percentage inside the storage tank

Plant cuttings decompose in compost. Which transfer returns some of their carbon to the atmosphere?

Dead organic material → decomposition and decomposer respiration → atmospheric carbon dioxide
Atmospheric carbon dioxide → combustion → dead organic material
Dead organic material → carbon atoms disappear → no destination store
Oxygen → photosynthesis → geological fuel

Which causal chain can connect the concentration change to enhanced greenhouse warming?

Atmospheric carbon dioxide at Mauna Loa

More greenhouse-gas molecules → more outgoing infrared absorbed and re-emitted → less energy escapes to space → average temperature can rise
More carbon dioxide → energy is created from nothing → every place has identical weather
More carbon dioxide → all incoming sunlight is permanently blocked → the natural effect ends
Higher concentration → carbon monoxide immediately reduces blood oxygen in every observer

A diagram shows atmospheric carbon dioxide → plant material, but a learner proposes repairing a fuel leak to label the missing arrow. Which response is correct?

Use photosynthesis for the arrow; repairing a leak is a control action, not a carbon-transfer label
Use respiration because every arrow into plants releases carbon dioxide
Use nitrogen because it is the largest gas in dry air
Use infrared absorption because every environmental arrow is a climate mechanism

G3 Science (Chemistry) Maintaining Air Quality · question set

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