The energy density of a fuel is the amount of useful energy stored in a specific amount of that fuel. The energy density, measured in megajoules per kilogram (MJ/kg), is related to the chemical composition of the fuel.
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.
Other Related Questions
Which statement describes one feature of the Rutherford-Bohr atom model that the Thomson model does not share?
- A. The Rutherford-Bohr model identifies different elements by the numbers of particles present.
- B. The Rutherford-Bohr model maintains the observed neutral charge of atoms.
- C. The Rutherford-Bohr model correctly describes the types of particles in the atom.
- D. The Rutherford-Bohr model restricts the positive charge of the atom to the nucleus.
Correct Answer & Rationale
Correct Answer: D
The Rutherford-Bohr model uniquely restricts the atom's positive charge to the nucleus, a significant advancement over the Thomson model, which depicts a diffuse positive charge throughout the atom. Option A is incorrect as both models can identify elements based on particle numbers, but the Rutherford-Bohr model adds more detail about electron arrangements. Option B is misleading; both models account for atomic neutrality, but the Rutherford-Bohr model provides a clearer structure. Option C is also inaccurate; while the Rutherford-Bohr model describes particles more accurately, it does not fundamentally change the types of particles present compared to Thomson's model.
The Rutherford-Bohr model uniquely restricts the atom's positive charge to the nucleus, a significant advancement over the Thomson model, which depicts a diffuse positive charge throughout the atom. Option A is incorrect as both models can identify elements based on particle numbers, but the Rutherford-Bohr model adds more detail about electron arrangements. Option B is misleading; both models account for atomic neutrality, but the Rutherford-Bohr model provides a clearer structure. Option C is also inaccurate; while the Rutherford-Bohr model describes particles more accurately, it does not fundamentally change the types of particles present compared to Thomson's model.
Scientists are Interested in whether certain greenhouse gases have helped cause I recent temperature increases. The graph presents data on carbon dioxide and methane gas levels in the atmosphere for the past several centuries. Human activities began producing large quantities of both gases in the 1700s. This graph, combined with information from--------------------, supports ----------------------.
- A. The Milankovitch climate change model
- B. paragraph 3
- C. The anthropogenic climate change model
- D. Paragraph 2
Correct Answer & Rationale
Correct Answer: B, C
The graph illustrates the correlation between rising greenhouse gas levels and temperature increases, supporting the anthropogenic climate change model, which attributes climate change to human activities. Options B and C effectively connect the visual data with the broader context of human influence on climate. Option A, referencing the Milankovitch model, is incorrect as this model focuses on natural Earth cycles, not human impact. Option D lacks specificity and does not directly relate to the evidence presented in the graph. Thus, B and C provide the most relevant support for understanding the relationship between greenhouse gas emissions and climate change.
The graph illustrates the correlation between rising greenhouse gas levels and temperature increases, supporting the anthropogenic climate change model, which attributes climate change to human activities. Options B and C effectively connect the visual data with the broader context of human influence on climate. Option A, referencing the Milankovitch model, is incorrect as this model focuses on natural Earth cycles, not human impact. Option D lacks specificity and does not directly relate to the evidence presented in the graph. Thus, B and C provide the most relevant support for understanding the relationship between greenhouse gas emissions and climate change.
Why is the conclusion about gene variation among cheetahs from Sommer's research more valid than the conclusion from O'Brien's research?
- A. Sommer's research was conducted more recently than O'Brien's
- B. Sommer's research used a different population of cheetahs than O'Brien's
- C. Sommer's conclusion is about disease response, while O'Brien's is about skin grafts.
- D. Sommer's conclusion is based on examining the genes, while O'Brien's conclusion is based on acceptance of a skin graft.
Correct Answer & Rationale
Correct Answer: D
Sommer's conclusion is more valid as it directly examines gene variation, providing a clearer understanding of genetic factors influencing traits. This direct analysis allows for more reliable insights into gene functionality. In contrast, O'Brien's research focuses on skin graft acceptance, which, while informative, does not provide the same depth of genetic examination. Option A is incorrect as recency does not inherently validate research findings. Option B is misleading; differing populations may affect findings but do not necessarily validate one conclusion over another. Option C misrepresents the focus of the studies; both are relevant but differ in application rather than validity.
Sommer's conclusion is more valid as it directly examines gene variation, providing a clearer understanding of genetic factors influencing traits. This direct analysis allows for more reliable insights into gene functionality. In contrast, O'Brien's research focuses on skin graft acceptance, which, while informative, does not provide the same depth of genetic examination. Option A is incorrect as recency does not inherently validate research findings. Option B is misleading; differing populations may affect findings but do not necessarily validate one conclusion over another. Option C misrepresents the focus of the studies; both are relevant but differ in application rather than validity.
Based on the table, use the drop-down menus to make the following statement correct. _ experiences the least warming effect from CO2 because it has the _ of CO2 in its atmosphere.
- A. smallest amount
- B. largest amount
- C. Mars
- D. Planet L
Correct Answer & Rationale
Correct Answer: A,C
The statement highlights that Mars experiences the least warming effect from CO2 due to its atmospheric composition. Mars has a small amount of CO2 compared to other planets, which limits its greenhouse effect and consequently its warming. Option B, "largest amount," is incorrect as it contradicts the premise that a larger CO2 presence would lead to more warming. Option D, "Planet L," is not a recognized celestial body in this context and does not provide relevant information regarding CO2 levels. Thus, the combination of Mars with the smallest amount of CO2 accurately reflects the relationship between atmospheric composition and warming effects.
The statement highlights that Mars experiences the least warming effect from CO2 due to its atmospheric composition. Mars has a small amount of CO2 compared to other planets, which limits its greenhouse effect and consequently its warming. Option B, "largest amount," is incorrect as it contradicts the premise that a larger CO2 presence would lead to more warming. Option D, "Planet L," is not a recognized celestial body in this context and does not provide relevant information regarding CO2 levels. Thus, the combination of Mars with the smallest amount of CO2 accurately reflects the relationship between atmospheric composition and warming effects.