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 between solid ammonium nitrate and water is endothermic, meaning it absorbs energy. Thus, the equation must reflect the consumption of energy during the process. Option B correctly shows that ammonium nitrate (NH4NO3) and water react to form ammonium hydroxide (NH4OH) and nitric acid (HNO3), while requiring energy input. Option A incorrectly suggests energy is released, which contradicts the endothermic nature of the reaction. Option C implies that energy is produced, which is also incorrect. Option D similarly misrepresents the reaction by suggesting energy is released, aligning with an exothermic process rather than the observed endothermic reaction.
The reaction between solid ammonium nitrate and water is endothermic, meaning it absorbs energy. Thus, the equation must reflect the consumption of energy during the process. Option B correctly shows that ammonium nitrate (NH4NO3) and water react to form ammonium hydroxide (NH4OH) and nitric acid (HNO3), while requiring energy input. Option A incorrectly suggests energy is released, which contradicts the endothermic nature of the reaction. Option C implies that energy is produced, which is also incorrect. Option D similarly misrepresents the reaction by suggesting energy is released, aligning with an exothermic process rather than the observed endothermic reaction.
Other Related Questions
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.
Which statement from the passage refutes Lavoisier's idea that heat is a fluid that leaves a hot substance and travels to a colder substance?
- A. He also found the brass filings produced from the drilling process contained enough heat to boil water while retaining their weight.
- B. James Joule discovered that heat could be produced by moving a wire through a magnetic field.
- C. Lavoisier demonstrated that oxygen was required for combustion.
- D. Count Rumford observed that the process of boring out cannons from brass cylinders continuously produced heat.
Correct Answer & Rationale
Correct Answer: A
Option A effectively refutes Lavoisier's notion of heat as a fluid by demonstrating that heat can be generated without the transfer of a fluid. The brass filings, despite retaining their weight, produced sufficient heat to boil water, indicating that heat can arise from mechanical processes rather than fluid movement. Option B, while highlighting Joule's discovery of heat production through motion, does not directly address Lavoisier's fluid concept. Option C focuses on combustion and oxygen's role, which is unrelated to the nature of heat itself. Option D describes an observation of heat generation during a mechanical process but does not emphasize the implications for Lavoisier's fluid theory as clearly as A does.
Option A effectively refutes Lavoisier's notion of heat as a fluid by demonstrating that heat can be generated without the transfer of a fluid. The brass filings, despite retaining their weight, produced sufficient heat to boil water, indicating that heat can arise from mechanical processes rather than fluid movement. Option B, while highlighting Joule's discovery of heat production through motion, does not directly address Lavoisier's fluid concept. Option C focuses on combustion and oxygen's role, which is unrelated to the nature of heat itself. Option D describes an observation of heat generation during a mechanical process but does not emphasize the implications for Lavoisier's fluid theory as clearly as A does.
If these results correctly predict the performance of this kneepad design, what is the probability that one of the kneepads will require a force of 145 N or greater to cause failure?
- A. 53%
- B. 22%
- C. 75%
- D. 25%
Correct Answer & Rationale
Correct Answer: D
To determine the probability of a kneepad requiring a force of 145 N or greater to cause failure, we analyze the data provided. The correct option, 25%, indicates that one-fourth of the kneepads are expected to fail under this force, aligning with statistical predictions for this design. Option A (53%) overestimates the likelihood, suggesting more than half will fail, which is not supported by the data. Option B (22%) underestimates the probability, indicating fewer kneepads will fail than expected. Option C (75%) is excessively high, implying a significant majority would fail, which contradicts the predicted performance. Thus, 25% accurately reflects the failure rate at this force threshold.
To determine the probability of a kneepad requiring a force of 145 N or greater to cause failure, we analyze the data provided. The correct option, 25%, indicates that one-fourth of the kneepads are expected to fail under this force, aligning with statistical predictions for this design. Option A (53%) overestimates the likelihood, suggesting more than half will fail, which is not supported by the data. Option B (22%) underestimates the probability, indicating fewer kneepads will fail than expected. Option C (75%) is excessively high, implying a significant majority would fail, which contradicts the predicted performance. Thus, 25% accurately reflects the failure rate at this force threshold.
A scientist studying solubility increased the temperature of a constant volume of water and measured the amount of sugar that dissolved into solution... Which of the following describes the relationship between the independent and dependent variables?
- A. As the amount of dissolved sugar increased, the temperature of the water decreased.
- B. As the water temperature increased, the amount of dissolved sugar increased.
- C. As the amount of dissolved sugar increased, the amount of water remained constant.
- D. As the water temperature increased, the amount of water decreased.
Correct Answer & Rationale
Correct Answer: B
Option B accurately describes the relationship between the independent variable (temperature of the water) and the dependent variable (amount of dissolved sugar). As temperature rises, solubility typically increases, allowing more sugar to dissolve. Option A incorrectly suggests an inverse relationship; higher temperatures do not cause the amount of dissolved sugar to decrease. Option C, while true, does not address the relationship between the two variables in question. Option D incorrectly implies that increasing temperature leads to a decrease in water volume, which is not relevant in this context.
Option B accurately describes the relationship between the independent variable (temperature of the water) and the dependent variable (amount of dissolved sugar). As temperature rises, solubility typically increases, allowing more sugar to dissolve. Option A incorrectly suggests an inverse relationship; higher temperatures do not cause the amount of dissolved sugar to decrease. Option C, while true, does not address the relationship between the two variables in question. Option D incorrectly implies that increasing temperature leads to a decrease in water volume, which is not relevant in this context.