Consider the following activities : 1. Spreading finely ground basalt rock on farmlands extensively 2. Increasing the alkalinity of oceans by adding lime 3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters How many of the above activities are often considered and discussed for carbon capture and sequestration?
- A.Only one
- B.Only two
- C.All three
- D.None
Correct answer
Explanation
The correct answer is C, All three. Each activity is a recognised way of pulling carbon dioxide out of circulation and locking it away.
Spreading crushed basalt on fields is called enhanced rock weathering: rainwater carrying carbon dioxide reacts with the calcium and magnesium in the rock to form stable carbonates and bicarbonates that wash into the sea. Adding lime or other alkaline minerals to seawater, known as ocean alkalinity enhancement, lets the ocean absorb more carbon dioxide from the air without becoming more acidic. Capturing carbon dioxide at factories and power plants, dissolving it in water and injecting it underground into rock formations or old mines is geological sequestration; in basalt the gas turns into solid carbonate within a few years, as the CarbFix project in Iceland has shown.
A is wrong because more than one activity qualifies. B is wrong because all three are discussed, not just two. D is wrong because each is a known carbon removal method.
Exam tip: rock weathering, ocean alkalinity and underground injection all lock carbon as carbonates.
Practice Questions
View allWhich of the following is/are renewable source(s) of energy? 1. Fossil fuel 2. Biofuel 3. Uranium 4. Hydropower Select the correct answer using the code given below.
- A.2 only
- B.3 and 4
- C.1 and 3
- D.2 and 4
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Biofuel and hydropower are renewable because nature replaces them within a human lifetime, while fossil fuels and uranium are not.
Read the full explanation →Which one of the following is NOT decomposed by bacterial action ?
- A.Vegetable remains
- B.Plastic materials
- C.Animal carcasses
- D.Wastes of flowers
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Ordinary plastics are non-biodegradable, so bacteria and fungi cannot break them down in any useful length of time. Most plastics, such as polyethylene, polypropylene and PVC, are long synthetic polymers made from petroleum.
Read the full explanation →According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
- A.Locomotives using fossil fuels
- B.Ships using fossil fuels
- C.Extraction of metals from ores
- D.Power plants using fossil fuels
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The EPA names the burning of fossil fuels by power plants and other industrial facilities as the largest source of sulphur dioxide.
Read the full explanation →Free swimming macroscopic animals in an aquatic environment are referred to as
- A.Plankton
- B.Periphyton
- C.Benthos
- D.Nekton
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Nekton are animals large enough to be seen with the naked eye that swim actively and can move against water currents.
Read the full explanation →Artificial way of causing rainfall to reduce air pollution makes use of
- A.silver iodide and potassium iodide
- B.silver nitrate and potassium iodide
- C.silver iodide and potassium nitrate
- D.silver nitrate and potassium chloride
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These salts are the usual seeding agents in cloud seeding, the artificial way to make rain. Cloud seeding sprays tiny particles into clouds that already hold moisture, from aircraft, rockets or ground generators.
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