QoW 2

Atmospheric CO2 dissolves in water to form carbonic acid, partially dissociating into bicarbonate and hydrogen ions. What is the pH of rainwater in equilibrium with 425 ppm CO2 in the atmosphere?

CO2 + H2O <-> H2CO3 <-> HCO3- + H+

Assume Keq=10^-6.35

Henry’s Constant for CO2 = 3.4 x 10^-2 M/atm

  1. 5.2

  2. 5.6

  3. 7.2

  4. 6.3

How is Bowen’s Reaction Series important in understanding New Hampshire’s bedrock?

  1. It illustrates the sequence of mineral crystallization from a magma as it cools, with Magnesium and Iron rich minerals forming first, which explains the composition of New Hampshire’s granite.

  2. It demonstrates the process of sedimentary rock formation through compaction of several sediments, and New Hampshire’s bedrock is largely sedimentary.

  3. It details the metamorphic transformations of rocks under high pressure and temperature conditions, and New Hampshire’s bedrock is largely metamorphic

  4. It is the main geologic process through which New Hampshire bedrock was formed.

Which of the following best explains why rain is naturally acidic (pH ~5.6)?

  1. Sulfur dioxide and nitrogen oxide from coal plants in the midwest mixed into the rain making it acidic.

  2. Carbon dioxide in the atmosphere dissolves into the water to form carbonic acid, lowering the pH.

  3. Rain absorbs salt from the ocean that lowers its pH when it falls.

  4. When oxygen in the atmosphere dissolves in water, it lowers the pH (which is why when taking water samples, we had to avoid any air bubbles).

Bill Gates has seen the error of his machine-oriented ways, and has decided to invest in a natural carbon capture project that spans many acid-polluted rivers in the US. Four companies have approached him with plans on how to implement this project, but only one has both a geologically correct solution and justification. As Gates’ geological consultant, which plan would you choose?

  1. Placing limestone blocks in rivers, as during the weathering process, carbonate rocks remove double the amount of carbon dioxide from the atmosphere that marine organisms will later release in the oceans, resulting in a net reduction of atmospheric CO2.

  2. Placing granite blocks in rivers, as silicate igneous rocks will weather far more quickly than carbonate rocks, thereby removing the same quantity of CO2 from the atmosphere in a shorter time frame.

  3. Placing limestone blocks in rivers, as through the weathering process, they will also help neutralize the acidity of the river through the release of alkaline ions, decreasing the river’s pH levels.

  4. Placing granite blocks in rivers, as during the weathering process, silicate rocks remove double the amount of carbon dioxide from the atmosphere that marine organisms will later release in the oceans, resulting in a net reduction of atmospheric CO2.

New Hampshire was formed from Gander, a volcanic island. As a result of Gander’s volcanic origin, NH’s bedrock was created from magma that rose to the surface and cooled gradually. Granite, an igneous rock, is one example of this type of bedrock. Which of the following statements is TRUE regarding the formation of Vermont and its bedrock?

  1. Vermont’s bedrock is primarily igneous, formed by magma rising to the surface and quickly cooling down, similar to New Hampshire.

  2. Vermont’s bedrock is largely composed of sedimentary rocks, which were formed by the intense heat and pressure from the volcanic island, Iapetus.

  3. Vermont’s bedrock is primarily granite formed by the layering of volcanic ash over millions of years.

  4. Vermont’s bedrock is largely composed of metamorphic rocks, which were formed by intense heat and pressure from existing sediments.

Would it be a more effective long-term ecocentric carbon sequestration strategy to add crushed limestone or crushed granite to waterways? Why?

  1. Limestone would be the more effective material in the long-term for carbon sequestration because it is a carbonate rock, through which the process of weathering will result in a net loss of CO2

  2. Granite would be the more effective material in the long-term for carbon sequestration because it is a carbonate rock, through which the process of weathering will result in a net loss of CO2

  3. Limestone would be the more effective material in the long-term for carbon sequestration because it is a silicate rock, through which the process of weathering will result in a net loss of CO2.

  4. Granite would be the more effective material in the long-term for carbon sequestration because it is a silicate rock, through which the process of weathering will result in a net loss of CO2

Given that the atmospheric CO2 in the mid-Oligocene period was about 680 ppm, which of the following conclusions can’t be drawn?

  1. During this period, the concentration of the atmospheric CO2 divided by the concentration of the aqueous CO2 is about 29.41 at m/M.

  2. The approximate pH of the rain in the Oligocene period is about 5.5.

  3. The Oligocene period had more atmospheric CO2 than present day.

  4. Present-day Earth atmosphere is warmer than it was during the mid-Oligocene.

What were the geologic processes that allowed the rocks in Vermont to be more susceptible to weathering than in New Hampshire?

  1. The rocks in Vermont were formed from volcanic activity, resulting in igneous rock types that were eroded by glaciers, making them more susceptible to weathering than the harder rocks in New Hampshire.

  2. Weathering and erosion from the Adirondack mountains and subsequent deposition in the Iapetus Ocean created sedimentary rocks that were metamorphosed and lifted after the land masses of Gander and Avalonia collided with the North American continent.

  3. Vermont’s rocks were created through continuous sediment deposition in freshwater lakes, which formed porous limestone beds that were easily weathered, unlike the solid granite found in New Hampshire.

  4. During the Paleozoic era, tectonic forces compressed Vermont’s rocks, turning them into soft, brittle shale, while New Hampshire’s rocks remained hard due to a lack of significant tectonic activity.

Which of the following scenarios is an example of Henry's Law in action?

  1. A bottle of carbonated soda fizzes when opened because the pressure of carbon dioxide above the drink decreases dramatically, and some of the dissolved CO2 leaves the liquid.

  2. Heating water increases the solubility of gas in water, causing it to produces bubbles as it boils/increases temperature. 

  3. As a diver descends deeper and deeper underwater, the amount of nitrogen dissolved in their bloodstream decreases because of the increased pressure.

  4. Breathing increases the partial pressure of oxygen in the lungs and results in less oxygen dissolving into the bloodstream.

  5. People named Henry choosing not to drink soda because they're allergic to carbonation.

What is the similarity between the creation of the Himalayas and the Appalachian mountains?

  1. Both were formed around the same time, approximately 50 million years ago. 

  2. Both the Himalayas and the Appalachian mountains are formed by subduction zones.

  3. The collisions that caused the Himalayas and the Appalachian Mountains are both formed by converging continental plates.

  4. The Himalayas and the Appalachian Mountains are still facing active and violent tectonic plate movement.

What is the reason(s) that makes granite rock so resistant to weathering? 

  1. Due to the low temperature that the minerals form at in a magma chamber, the minerals become tightly interlocked with one another. 

  2. Due to the mafic silicate minerals that precipitate out of a magma chamber to form granite—olivine and pyroxene. These specific types of minerals are the most resistant to weathering.

  3. Due to the presence of quartz. It is cemented by calcium carbonate in granite which helps make the rock resistant to weathering. 

  4. Due to the high temperature that the minerals form at in a magma chamber, the minerals are able to tightly interlock with one another. 

  5. both A and C 

  6. all options/reasons

Based on your knowledge of rock formation and plate tectonics, which of the following situations would most likely create a mountain range of igneous rock?

  1. A high pressure collision that traps sediments, such as the one between Gander Island and North America to form Vermont, would pressurize these sediments and cause them to meld together into igneous rock. 

  2. The rifting between two plates would cause magma to rise up from beneath the Earth’s surface and bulge, creating a mountain range of granite as the magma slowly cooled and large crystals formed.

  3. A high energy continental collision would generate enough pressure to force one plate beneath another while friction melted the top of the plunging continent. A mountain range would form as the plates scrape against each other, and the melted rock is forced upwards, then cooling slowly and creating interlocking minerals and an igneous mountain range.

  4. A high energy continental collision would cause the rocks to melt as the same light felsic rock composition of each continent causes the continents to resist plunging beneath each other. A mountain range forms as the high energy collision creates heat and pressure that melts the rock and forces it upwards.

Which of the following statements about subduction and the partial melting of basalt is incorrect?

  1. The felsic minerals are the first to melt into magma during subduction

  2. The mafic minerals melt into magma at very high temperatures

  3. The felsic minerals accumulate at the crust

  4. The mafic minerals form a continental craton

Which of the following is correct?

  1. Quartz hydrolysis results in calcium, potassium, and sodium ions as well as clays

  2. Olivine and Pyroxene are the hardest to weather because they were formed at such a high extreme temperature, so the rock is very resistant to any sort of weathering

  3. Granite is often found in mountain ranges because when two continental plates collide, the collision of the rock creates a similar environment to a magma chamber which then forms granite

  4. Carbonate weathering businesses have been getting a lot of attention because the entire process of carbonate weathering takes in 2 CO2 for every CO it gives back out (effectively sucking CO2 out of the air)

In the context of the rock cycle, how do tectonic forces contribute to the transformation of sedimentary rocks into metamorphic rocks?

  1. By facilitating the erosion and transportation of sediments

  2. By subjecting the rocks to intense heat and pressure 

  3. By causing rapid cooling and crystallization of molten rock

  4. By exposing the rocks to prolonged contact with water, leading to dissolution 

Based on what we learned in class, which of the following carbon capture strategies would be the most effective at sequestering CO2 from the atmosphere and not releasing it back up? 

  1. Putting lots of limestone in rivers so that CO2 can be sequestered through a chemical reaction and turned into bicarbonate and calcium. This bicarbonate and calcium would then flow into the oceans and be used to form shells. 

  2. Starting a hypothetical program that removes limestone from all riverbeds so that the chemical reaction between CO2 and calcium carbonate cannot occur in riverbeds. 

  3. Spreading fine rock particles that are high in silica around farms and other fields to react with acidic rainwater and sequester carbon. 

  4. Releasing silica rich rock underwater in rivers to have it mix with the river water and perform silicate weathering to sequester carbon.

Which of the following is TRUE regarding the minerals in Bowen’s reaction series?

  1. More mafic minerals like olivine and pyroxene solidify at lower temperatures, are lighter, and therefore rise to the top of magma chambers.

  2. The felsic mineral quartz is one of the weakest, most easily weathered minerals.

  3. More felsic minerals like quartz and muscovite solidify at higher temperatures, are denser, and therefore sink to the bottom of magma chambers.

  4. Bowen’s reaction series is inversely related to Goldrich’s weathering series because minerals like olivine are less thermodynamically stable and Earth's surface temperatures.

What piece of information does NOT support an argument against investing in carbon sequestration machines?

  1. Carbon sequestration machines are expensive, usually hundreds of millions of dollars.

  2. A company that takes 350 tons of of carbon out of the atmosphere may only be accounting for a very small fraction of a percent of the carbon we emit annually

  3. The weathering of volcanic/igneous rock in rivers captures carbon from the atmosphere naturally.

  4. The weathering of silicates like limestone in rivers captures carbon from the atmosphere naturally.