In 1908, a huge explosion known as the Tunguska Event flattened trees for miles across a remote area of Russia. Scientists now think an asteroid or a comet entered Earth's atmosphere, causing the explosion. Ice core samples from an ice sheet in Greenland reveal signs of this enormous explosion: deposits of ammonia equal to 5 micrograms per square meter. But how exactly did these telltale molecules form?
• Hypothesis 1: The Tunguska explosion started forest fires, known to produce ammonia. Data indicates that such fires would have deposited an amount of ammonia over the Northern Hemisphere equaling 0.1 micrograms per square meter.
• Hypothesis 2: Up to 1% of the object's mass might have been ammonia, and this ammonia might have spread over the Northern Hemisphere. Approximately 0.00005 micrograms of ammonia per square meter are predicted by this hypothesis.
• Hypothesis 3: Since many compounds form in the presence of high heat, the ammonia could
have been produced as the falling object heated the atmosphere. However, heat alone is not
sufficient to cause the formation of ammonia.
• Hypothesis 4: As it passed through the atmosphere, the object pushed air in front of it at high pressure. Nitrogen and hydrogen combine to form ammonia under similar pressure. Considering the amount of hydrogen expected in a comet and the available nitrogen in Earth's atmosphere, approximately 5 micrograms of ammonia per square meter would have been deposited under this hypothesis.
best explains the ammonia deposits found in ice core samples from the time of the Tunguska Event. The evidence that best supports the validity of this hypothesis is the-
- A. Hypothesis 2
- B. heat produced by fast-moving objects in the atmosphere
- C. Hypothesis 1
- D. match between measured and predicted amounts of ammonia
Correct Answer & Rationale
Correct Answer: A,D
The ammonia deposits found in ice core samples from the time of the Tunguska Event suggest a significant environmental impact. Hypothesis 2 (Option A) likely proposes a link between the event and the ammonia presence, making it relevant for explaining the deposits. Option B, which discusses heat from fast-moving objects, does not directly address ammonia production or accumulation. Hypothesis 1 (Option C) may not provide sufficient evidence or detail to support the ammonia findings. Option D highlights the alignment between measured and predicted ammonia levels, reinforcing the validity of Hypothesis 2 as it connects empirical data with theoretical expectations.
The ammonia deposits found in ice core samples from the time of the Tunguska Event suggest a significant environmental impact. Hypothesis 2 (Option A) likely proposes a link between the event and the ammonia presence, making it relevant for explaining the deposits. Option B, which discusses heat from fast-moving objects, does not directly address ammonia production or accumulation. Hypothesis 1 (Option C) may not provide sufficient evidence or detail to support the ammonia findings. Option D highlights the alignment between measured and predicted ammonia levels, reinforcing the validity of Hypothesis 2 as it connects empirical data with theoretical expectations.
Other Related Questions
Which statement describes the motion of the object for the first 10 seconds?
- A. The object is moving at a constant speed.
- B. The object is doubling its speed every two seconds.
- C. The object is increasing its height.
- D. The object is accelerating.
Correct Answer & Rationale
Correct Answer: D
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
Placing solid ammonium nitrate, NH4NO3, in a container of water causes an endothermic reaction. The result is ammonium hydroxide, NH4OH, and nitric acid, HNO3. Which diagram shows the correct equation for the reaction?
- A. NH4OH + HNO3 → NH4NO3 + H2O + energy
- B. NH4NO3 + H2O + energy → NH4OH + HNO3
- C. NH4NO3 + H2O → NH4OH + HNO3 + energy
- D. NH4OH + HNO3 + energy → NH4NO3 + H2O
Correct Answer & Rationale
Correct Answer: B
The reaction involving solid ammonium nitrate and water is endothermic, meaning it absorbs energy. Option B accurately reflects this by showing ammonium nitrate and water reacting to form ammonium hydroxide and nitric acid while requiring energy input, consistent with the endothermic nature of the process. Option A incorrectly suggests that energy is released, which contradicts the reaction's endothermic characteristic. Option C also misrepresents the energy aspect, implying that energy is produced, which is not the case. Option D similarly indicates that energy is released, misaligning with the reaction's true nature.
The reaction involving solid ammonium nitrate and water is endothermic, meaning it absorbs energy. Option B accurately reflects this by showing ammonium nitrate and water reacting to form ammonium hydroxide and nitric acid while requiring energy input, consistent with the endothermic nature of the process. Option A incorrectly suggests that energy is released, which contradicts the reaction's endothermic characteristic. Option C also misrepresents the energy aspect, implying that energy is produced, which is not the case. Option D similarly indicates that energy is released, misaligning with the reaction's true nature.
The chemical composition and energy density of four fuels are shown in the table. Ethane, which has a chemical composition of C2H6, is also a fuel. What is the predicted energy density of ethane?
- A. 45 MJ/kg
- B. 42 MJ/kg
- C. 52 MJ/kg
- D. 48 MJ/kg
Correct Answer & Rationale
Correct Answer: C
To determine the predicted energy density of ethane (C2H6), one can analyze its molecular structure and compare it to the energy densities of similar hydrocarbons listed in the table. Ethane, being an alkane, typically has a higher energy density due to its saturated carbon-hydrogen bonds. Option A (45 MJ/kg) is lower than expected for alkanes of similar size. Option B (42 MJ/kg) underestimates the energy density, as it does not align with the general trend for hydrocarbons. Option D (48 MJ/kg) is closer but still below the typical range for ethane. Thus, option C (52 MJ/kg) aligns with the expected energy density for ethane, reflecting its molecular composition and energy potential.
To determine the predicted energy density of ethane (C2H6), one can analyze its molecular structure and compare it to the energy densities of similar hydrocarbons listed in the table. Ethane, being an alkane, typically has a higher energy density due to its saturated carbon-hydrogen bonds. Option A (45 MJ/kg) is lower than expected for alkanes of similar size. Option B (42 MJ/kg) underestimates the energy density, as it does not align with the general trend for hydrocarbons. Option D (48 MJ/kg) is closer but still below the typical range for ethane. Thus, option C (52 MJ/kg) aligns with the expected energy density for ethane, reflecting its molecular composition and energy potential.
Based on these results and assuming that whenever two materials are present their remaining energy is averaged, what would the scientist best conclude to be the composition of Saturn's rings?
- A. equal amounts of loose rocks and loose snow
- B. equal amounts of ice and bedrock
- C. a small amount of bedrock and a large amount of carbon rock
- D. large amounts of ice and smaller amounts of carbon rock
Correct Answer & Rationale
Correct Answer: D
The conclusion about Saturn's rings is supported by the composition of ice and carbon rock. Large amounts of ice are consistent with observations of Saturn’s rings, which are primarily composed of water ice particles. Smaller amounts of carbon rock align with the presence of darker materials found in the rings. Options A and B suggest equal amounts of materials that do not reflect the observed predominance of ice. Option C overestimates the presence of bedrock, which is not supported by scientific data. Thus, option D accurately captures the dominant composition of Saturn's rings.
The conclusion about Saturn's rings is supported by the composition of ice and carbon rock. Large amounts of ice are consistent with observations of Saturn’s rings, which are primarily composed of water ice particles. Smaller amounts of carbon rock align with the presence of darker materials found in the rings. Options A and B suggest equal amounts of materials that do not reflect the observed predominance of ice. Option C overestimates the presence of bedrock, which is not supported by scientific data. Thus, option D accurately captures the dominant composition of Saturn's rings.