Environmental and Atmospheric Chemistry — Free IB MYP4 Chemistry Questions

1QuestionLayers of the atmosphere (troposphere, stratosphere, etc.)Concept Practice

2 marks~3 minCriterion A

The diagram below shows a vertical cross-section of Earth's atmosphere.

Troposphere: 0–12 km
?: 12–50 km
Mesosphere: 50–85 km
Thermosphere: 85–600 km

a

Identify the atmospheric layer indicated by the question mark. [1]

b

The layer you identified in (a) shows an unusual temperature profile compared with the troposphere. Explain why temperature increases with altitude in this layer. [1]

Solutions

2QuestionComplete vs incomplete combustionConcept Practice

2 marks~3 minCriterion B

Four trials of burning methane (

\text{CH}_4

) are conducted, each using 5.0 g of fuel. The oxygen-to-fuel ratio is varied across trials.

Trial	1	2	3	4
Oxygen-to-fuel ratio	1.5:1	2.0:1	2.5:1	3.0:1
Flame colour	yellow	orange-yellow	blue-yellow	blue
Soot produced	heavy	moderate	slight	none

a

Deduce the relationship between oxygen-to-fuel ratio and soot production shown by these results. [1]

b

Identify the controlled variable and the manipulated variable in this experiment. [1]

Solutions

3QuestionComplete vs incomplete combustionConcept Practice

3 marks~5 minCriterion A

A Bunsen burner produces two distinct flames depending on the position of the air hole: Flame A (air hole open, blue flame) and Flame B (air hole closed, yellow flame). The fuel burned is methane (

CH_4

).

a

Identify which flame represents complete combustion. [1]

b

Explain why Flame A and Flame B produce different combustion products, referring to oxygen availability and the specific products formed in each case. [2]

Solutions

4QuestionSources of greenhouse gas emissionsConcept Practice

2 marks~3 minCriterion A

The diagram shows a molecule with a central carbon atom bonded to four hydrogen atoms in a tetrahedral arrangement.

a

Identify the molecule shown, giving its chemical formula. [1]

b

State one human-related activity that releases this molecule into the atmosphere. [1]

Solutions

5QuestionEffects on soil, water bodies, and buildingsConcept Practice

2 marks~3 minCriterion A

The photograph shows a limestone statue damaged by acid rain. The statue's surface is pitted and fine carved details have been lost.

Acid rain forms when sulfur dioxide and nitrogen oxides dissolve in atmospheric water.

a

Identify one acidic substance present in acid rain that reacts with calcium carbonate (

CaCO_3

) in limestone. [1]

b

The reaction between the acid and limestone produces a salt, water, and carbon dioxide gas. Deduce the type of chemical reaction occurring, and explain how the production of

CO_2

gas contributes to the physical erosion of the statue's surface. [1]

Solutions

6QuestionUV radiation and its harmful effectsConcept Practice

2 marks~3 minCriterion A

The diagram below shows the ozone layer absorbing incoming ultraviolet (UV) radiation from the Sun. A magnified circle highlights a single molecule of ozone.

a

Identify the molecule shown in the magnified circle, giving its chemical formula. [1]

b

Explain one harmful effect of UV radiation on human health. [1]

Solutions

7QuestionLife cycle of materials (production → use → disposal)Concept Practice

2 marks~3 minCriterion A

The diagram below shows the life cycle of a plastic bottle, with stages labelled A to F.

Stage A: Extraction of crude oil
Stage B: Refining of crude oil into naphtha
Stage C: Polymerisation of monomers into polymer pellets
Stage D: Moulding of pellets into bottles
Stage E: Use of the bottle
Stage F: Disposal in landfill or recycling

a

Identify the stage at which the material is first produced as a polymer. [1]

b

Explain why the material at Stage B cannot be classified as a polymer. [1]

Solutions

8QuestionStages of water treatment (filtration, sedimentation, chlorination)Concept Practice

2 marks~3 minCriterion A

A water treatment plant receives river water containing suspended soil particles, algae, and fine sediment. The water first enters a large open tank, labelled X, where it is left undisturbed for several hours. Heavier particles gradually collect at the bottom, and clearer water is drawn off near the surface.

a

Identify tank X. [1]

b

Explain why leaving water undisturbed in tank X is more effective at removing particles when the particles are larger and denser. [1]

Solutions

9QuestionVariable components (water vapor, pollutants)Assessment Practice

2 marks~3 minCriterion B

A student uses silica gel to absorb water vapour from sealed containers at five different humidity levels. The results are recorded below.

Humidity (\%)	30	40	50	60	70
Mass of water absorbed (g)	1.2	1.6	2.0	2.4	2.8

a

Deduce the relationship between humidity and the mass of water absorbed by the silica gel. [1]

b

A weather station reports that high indoor humidity accelerates corrosion of metal equipment. Using the pattern in the data, predict the mass of water absorbed at 80\% humidity, and explain whether silica gel would be an effective control measure in this context. [1]

Solutions

10QuestionRole of oxygen in respiration and combustionAssessment Practice

2 marks~3 minCriterion D

Wastewater treatment plants use aeration systems to supply oxygen to aerobic bacteria, which decompose organic pollutants through cellular respiration. Monitoring dissolved oxygen (DO) levels is critical to maintaining this process.

a

Outline one real-world application of oxygen's role in aerobic respiration in wastewater treatment. [1]

b

Discuss one environmental impact that could result if dissolved oxygen levels in the treatment system fall below the threshold required for aerobic respiration. [1]

Solutions

11QuestionRole of oxygen in respiration and combustionAssessment Practice

5 marks~8 minCriterion C

A student investigates the hypothesis: Oxygen is required for combustion. Three experiments each use a 0.50 g strip of magnesium ribbon burned in different atmospheres; the mass of solid product is recorded after burning.

Experiment 1 (normal air)	initial mass = 0.50 g	final mass = 0.83 g
Experiment 2 (pure oxygen)	initial mass = 0.50 g	final mass = 0.83 g
Experiment 3 (pure nitrogen)	initial mass = 0.50 g	final mass = 0.50 g

a

Calculate the mass gain in Experiment 1 and write the balanced equation for the reaction that produced this gain. [2]

b

Explain why Experiments 1 and 2 produce identical final masses, yet Experiment 3 shows no mass change. [2]

c

Evaluate whether the three experiments together support or refute the hypothesis, identifying the specific role of oxygen in the combustion of magnesium. [1]

Solutions

12QuestionFormation of carbon monoxide and sootAssessment Practice

5 marks~8 minCriterion C

A student burns methane (

CH_4

) in a sealed chamber at three oxygen concentrations. The measured yields of carbon monoxide (

CO

) and soot are recorded below.

Oxygen concentration (percent)	10	15	21
$CO$ yield (g)	8.0	4.5	1.0
Soot yield (g)	3.5	1.8	0.2

a

Describe the trend shown in the data for both

CO

and soot yields as oxygen concentration increases from 10 percent to 21 percent. [1]

b

Write a balanced chemical equation for the complete combustion of methane, then write one equation showing an incomplete combustion pathway that produces

CO

only. Use these equations to explain why lower oxygen concentration favours

CO

and soot formation. [2]

c

Evaluate whether the data support the hypothesis that insufficient oxygen increases

CO

and soot formation. In your answer, identify one specific limitation of this experiment and justify how it affects confidence in the conclusion. [2]

Solutions

13QuestionHydrocarbon fuels (fossil fuels vs biofuels)Assessment Practice

6 marks~9 minCriterion D

A student compares corn-based ethanol (biofuel) and gasoline (fossil fuel) as transport fuels.

Data per litre of fuel:

CO

_2

released on combustion — ethanol: 1.52 kg; gasoline: 2.31 kg

CO

_2

absorbed during production — ethanol (corn growth): 1.52 kg; gasoline: 0 kg

a

Calculate the net CO

_2

contribution (CO

_2

released − CO

_2

absorbed) per litre for each fuel. Show your working. [2]

b

Deduce which fuel has the smaller net impact on atmospheric CO

_2

levels. Use your calculated values to support your reasoning. [2]

c

Analyse one limitation of using only combustion CO

_2

data to compare the overall environmental impact of these two fuels. [2]

Solutions

14QuestionSources of greenhouse gas emissionsAssessment Practice

6 marks~9 minCriterion B

The table below shows total annual greenhouse gas emissions (million tonnes of

\text{CO}_2

-equivalent) for four countries in 2000 and 2020.

Country A — 2000: $\text{CO}_2$ 450, $\text{CH}_4$ 120, $\text{N}_2\text{O}$ 40	2020: $\text{CO}_2$ 380, $\text{CH}_4$ 110, $\text{N}_2\text{O}$ 50
Country B — 2000: $\text{CO}_2$ 600, $\text{CH}_4$ 200, $\text{N}_2\text{O}$ 60	2020: $\text{CO}_2$ 550, $\text{CH}_4$ 180, $\text{N}_2\text{O}$ 65
Country C — 2000: $\text{CO}_2$ 300, $\text{CH}_4$ 80, $\text{N}_2\text{O}$ 30	2020: $\text{CO}_2$ 280, $\text{CH}_4$ 75, $\text{N}_2\text{O}$ 35
Country D — 2000: $\text{CO}_2$ 520, $\text{CH}_4$ 150, $\text{N}_2\text{O}$ 50	2020: $\text{CO}_2$ 490, $\text{CH}_4$ 250, $\text{N}_2\text{O}$ 55

a

Describe the overall trend in

\text{CO}_2

emissions across all four countries from 2000 to 2020. [1]

b

Deduce which country shows an anomalous change in

\text{CH}_4

emissions. Support your answer with a calculated percentage change and a comparison with the other three countries. [3]

c

Analyse how an error in applying global warming potential (GWP) conversion factors could produce the anomaly identified in (b), and explain what effect correcting this error would have on the reported total emissions for that country. [2]

Solutions

15QuestionSources of greenhouse gas emissionsAssessment Practice

5 marks~8 minCriterion D

A student investigates the hypothesis: "Methane (CH

_4

) is a more potent greenhouse gas per molecule than carbon dioxide (CO

_2

)." Infrared (IR) absorbance is measured for each pure gas at six concentrations using a fixed path length of 10 cm. CH

_4

is tested at 7.7 μm; CO

_2

at 15 μm.

Concentration (

\times 10^{18}

molecules/cm

^3

): 0.5, 1.0, 2.0, 3.0, 4.0, 5.0

Absorbance for CH

_4

(arbitrary units): 0.10, 0.20, 0.40, 0.60, 0.80, 1.00

Absorbance for CO

_2

(arbitrary units): 0.02, 0.04, 0.08, 0.12, 0.16, 0.20

a

Calculate the absorbance per molecule for CH

_4

and for CO

_2

, using the data at

1.0 \times 10^{18}

molecules/cm

^3

. [2]

b

Using your results from (a), deduce the ratio of IR absorbance per molecule for CH

_4

relative to CO

_2

, and state whether the data supports the hypothesis. [1]

c

Evaluate the reliability of this experiment as evidence for the real-world greenhouse potency of CH

_4

compared with CO

_2

. Identify two limitations and suggest one improvement. [2]

Solutions

16QuestionGreenhouse effect mechanismAssessment Practice

6 marks~9 minCriterion C

Analyze the following data that presents the infrared (IR) absorption strength and atmospheric concentration of four greenhouse gases.

Gas: CO2, CH4, H2O, N2O

Concentration (ppm): 415, 1.9, 4000 (variable), 0.33

IR absorption at 10 μm (relative units): 0.8, 0.5, 1.0, 0.2

a

Identify the anomaly in the relationship between atmospheric concentration and IR absorption strength based on the data provided. [2]

b

Explain why methane (CH4) absorbs IR radiation more efficiently per molecule than carbon dioxide (CO2), despite its lower concentration. In your response, refer to the molecular structure and vibrational modes of both gases. [3]

c

State one implication of this anomaly for the global warming potential (GWP) of methane compared to carbon dioxide. [1]

Solutions

17QuestionFormation of acid rain (SO₂ and NOx reactions)Assessment Practice

3 marks~5 minCriterion B

The table below shows annual

NO_2

emissions and average rainwater pH for a city over five years.

Year	2018	2019	2020	2021	2022
$NO_2$ emissions (tonnes)	1200	1150	1080	950	870
Average rainwater pH	5.2	5.3	5.5	5.7	5.9

a

Identify the relationship between

NO_2

emissions and rainwater pH over the five-year period. [1]

b

State the balanced chemical equation for the reaction of

NO_2

with water and oxygen to form nitric acid. [1]

c

Analyse how the change in

NO_2

emissions accounts for the observed trend in rainwater pH, using your equation from (b) in your reasoning. [1]

Solutions

18QuestionEffects on soil, water bodies, and buildingsAssessment Practice

5 marks~8 minCriterion D

A farmer in a region affected by acid rain observes declining crop yields. Soil tests reveal elevated aluminium ion (

Al^{3+}

) concentrations. Acid rain (pH ≈ 4.5) reacts with aluminium silicate minerals in the soil:

Al_2Si_2O_5(OH)_4(s) + 6H^+(aq) \rightarrow 2Al^{3+}(aq) + 2SiO_2(s) + 5H_2O(l)

The farmer considers applying lime (

CaCO_3

) to neutralise soil acidity:

CaCO_3(s) + 2H^+(aq) \rightarrow Ca^{2+}(aq) + H_2O(l) + CO_2(g)

a

Explain how acid rain causes aluminium ions to leach into the soil solution. In your answer, refer to the role of

H^+

ions and the equation above. [2]

b

Discuss TWO limitations of applying lime across a large agricultural area to reduce aluminium leaching. [3]

Solutions

19QuestionFormation of acid rain (SO₂ and NOx reactions)Assessment Practice

6 marks~9 minCriterion C

A sealed chamber containing air, water vapour, and UV light was injected with

SO_2

and

NO_2

. Concentrations were measured over 60 minutes.

Time (min)	0	10	20	30	40	50	60
$SO_2$ (ppm)	100	85	72	60	50	42	35
$NO_2$ (ppm)	80	65	52	40	30	22	15
$H_2SO_4$ (ppm)	0	15	28	40	50	58	65

The proposed reaction pathway is:

SO_2 + NO_2 \rightarrow SO_3 + NO

SO_3 + H_2O \rightarrow H_2SO_4

a

Describe the trends in the concentrations of

SO_2

,

NO_2

, and

H_2SO_4

over the 60-minute period. [2]

b

Explain how the 1:1 decrease in

SO_2

and

NO_2

concentrations, and the corresponding increase in

H_2SO_4

, are consistent with the proposed reaction pathway. [2]

c

Evaluate whether the data provides sufficient evidence to conclude that

NO_2

is the oxidising agent for

SO_2

in this system. Suggest one additional measurement that would strengthen this conclusion. [2]

Solutions

20QuestionUV radiation and its harmful effectsAssessment Practice

6 marks~9 minCriterion B

Ground-level UV-B intensity was measured at five sites with different ozone column thicknesses on the same day under clear-sky conditions.

Ozone thickness (DU)	200	250	300	350	400
UV-B intensity (W m $^{-2}$ )	2.5	1.9	2.1	1.1	0.7

a

Describe the general trend between ozone column thickness and UV-B intensity shown in the data. [2]

b

Identify the data point that does not fit the general trend and deduce what UV-B intensity value would be expected at that ozone thickness. [2]

c

Explain why the anomalous data point is physically impossible, with reference to how ozone absorbs UV-B radiation. [2]

Solutions

21QuestionInternational agreements (e.g., Montreal Protocol)Assessment Practice

2 marks~3 minCriterion D

The Montreal Protocol (1987) is an international agreement that phased out the production and use of chlorofluorocarbons (CFCs).

a

Explain how banning CFCs under the Montreal Protocol reduces ozone depletion in the stratosphere. [1]

b

Identify one limitation that reduces the effectiveness of the Montreal Protocol in protecting the ozone layer. [1]

Solutions

22QuestionOzone hole formation (especially over Antarctica)Assessment Practice

5 marks~8 minCriterion C

The table below shows the average October ozone column thickness (in Dobson Units, DU) over Halley Bay, Antarctica, and the global average atmospheric concentration of CFC-11 (in parts per trillion by volume, pptv) for selected years.

Year	1975	1978	1980	1982	1984	1985
Ozone column (DU)	290	270	250	220	200	180
CFC-11 (pptv)	120	140	160	185	210	225

a

Describe the trend in each dataset between 1975 and 1985. [1]

b

Identify the correlation between ozone column thickness and CFC-11 concentration, and explain how this relationship is consistent with the catalytic destruction of ozone by chlorine radicals. [2]

c

Evaluate the strength of this dataset as evidence for the hypothesis that CFCs cause ozone depletion. [2]

Solutions

23QuestionTypes of recyclable materials (plastics, metals, glass)Assessment Practice

6 marks~9 minCriterion A

The diagram below shows the repeating units of two polymers used in plastic bottles.

PET (polyethylene terephthalate):

-\mathrm{O}-\mathrm{CH_2}-\mathrm{CH_2}-\mathrm{O}-\mathrm{C}(=\mathrm{O})-\mathrm{C_6H_4}-\mathrm{C}(=\mathrm{O})-

linked by ester bonds

(-\mathrm{C}(=\mathrm{O})-\mathrm{O}-)

.

HDPE (high-density polyethylene):

-\mathrm{CH_2}-\mathrm{CH_2}-

linked by carbon–carbon single bonds.

a

Identify the type of bond that links monomers in each polymer. [2]

b

Explain why PET, but not HDPE, can be depolymerized by hydrolysis to recover its original monomers. [2]

c

Evaluate which polymer is more suitable for chemical recycling, referring to the products obtained and the conditions required for each breakdown process. [2]

Solutions

24QuestionLife cycle of materials (production → use → disposal)Assessment Practice

3 marks~5 minCriterion D

The diagram below shows the life cycle of a polyethene bottle: ethene monomers are polymerised, the bottle is used for packaging, and then disposed of in a landfill site.

a

Identify the type of bonding present in polyethene. [1]

b

Apply your knowledge of bonding to explain why polyethene is resistant to decomposition in the landfill. Refer to the bonds present in the polymer chain. [1]

c

Evaluate whether disposing of polyethene in a landfill is a sustainable end-of-life option. Use evidence from the life cycle shown in the diagram. [1]

Solutions

25QuestionLife cycle of materials (production → use → disposal)Assessment Practice

6 marks~9 minCriterion C

A hypothesis states: 'All bioplastics fully decompose within 90 days under industrial composting conditions.'

To test this, the mass loss of polylactic acid (PLA) and polyethylene terephthalate (PET) was measured over 60 days at 58 °C and 60% humidity.

Day	15	30	45	60
PLA mass loss (%)	12	25	40	55
PET mass loss (%)	1	2	3	4

a

Calculate the average rate of mass loss for PLA over the 60-day period. Give your answer in % per day. [2]

b

Using your answer to (a) and specific data from the table, explain why the data does not fully support the hypothesis. [2]

c

Evaluate whether this experiment is sufficient to conclude that the hypothesis is false for all bioplastics. Justify your answer using evidence from the data and the experimental design. [2]

Solutions

26QuestionRole of chlorine and disinfection methodsAssessment Practice

2 marks~3 minCriterion B

A water treatment plant disinfects drinking water by adding chlorine to eliminate E. coli. The data below show the contact time required to kill 99.9% of E. coli at 20°C.

Chlorine dose (mg/L)	0.5	1.0	1.5	2.0
Contact time (min)	12	6	4	3

a

Deduce the mathematical relationship between chlorine dose and contact time, showing clearly how the data support your answer. [1]

b

A treatment plant operates at a chlorine dose of 2.5 mg/L but must achieve 99.9% kill of E. coli within 2 minutes. Evaluate whether this dose is sufficient, using your relationship from (a). [1]

Solutions

27QuestionRemoval of suspended vs dissolved impuritiesAssessment Practice

7 marks~11 minCriterion D

A student hypothesises that aluminium sulfate (alum) is more effective than ferric chloride at removing suspended clay particles from river water. Three 300 mL portions of river water (initial turbidity 100 NTU each) are treated: 0.5 g alum, 0.5 g ferric chloride, and no coagulant (control). Each portion is stirred for 2 minutes, then turbidity is recorded every 5 minutes for 30 minutes.

Turbidity readings (NTU):

Time (min)	0	5	10	15	20	25	30
Control	100	95	95	95	95	95	95
Alum	100	30	20	20	20	20	20
Ferric chloride	100	50	35	35	35	35	35

a

Calculate the percentage reduction in turbidity for alum and for ferric chloride after 30 minutes. [2]

b

Analyse the rate of turbidity reduction for each coagulant between 0 and 10 minutes, using data from the table. [2]

c

Evaluate whether the experimental evidence supports the hypothesis. In your answer, identify one limitation of the experimental design and explain how it affects the validity of the conclusion. [3]

Solutions

28QuestionRole of chlorine and disinfection methodsAssessment Practice

5 marks~8 minCriterion C

Students investigated chlorine disinfection by treating water samples contaminated with Escherichia coli at 10,000 CFU/mL. Each sample received one of four chlorine concentrations (0.1, 0.5, 1.0, or 2.0 mg/L), and bacterial counts were recorded after 5, 15, and 30 minutes. The graph below shows the results.

The hypothesis states: "Chlorine kills bacteria by disrupting cell membranes through oxidation."

a

State two trends shown in the graph relating chlorine concentration or contact time to bacterial survival. [1]

b

Explain how chlorine forms an active disinfectant species in water and why this species is effective at damaging bacterial cells. [2]

c

Evaluate whether the experimental evidence supports the hypothesis. In your answer, refer to what the data can and cannot confirm about the proposed mechanism. [2]

Solutions

Environmental and Atmospheric Chemistry — Free MYP4 Chemistry Practice Questions