Limestone and marble are often used in buildings. Both types of rock contain calcium carbonate, which is sensitive to chemical weathering by acids. A scientist conducted an experiment to test the effect of acid strength on calcium carbonate... Which change would reduce the possibility of error in the experiment?
- A. performing the experiment with a different acid in the solution
- B. performing multiple trials for each solution pH
- C. using more of the acidic solution
- D. using a solution with a pH below 3.00
Correct Answer & Rationale
Correct Answer: B
Performing multiple trials for each solution pH enhances the reliability of the experiment by allowing for the identification of consistent patterns and minimizing the impact of random errors. This approach provides a more accurate average result, leading to valid conclusions about the effect of acid strength on calcium carbonate. Option A introduces a variable that may not be relevant to the original question, potentially complicating the results. Option C does not address the variability inherent in a single trial, which could skew results. Option D restricts the experiment to a specific range of acidity, limiting the exploration of acid strength effects across a broader spectrum.
Performing multiple trials for each solution pH enhances the reliability of the experiment by allowing for the identification of consistent patterns and minimizing the impact of random errors. This approach provides a more accurate average result, leading to valid conclusions about the effect of acid strength on calcium carbonate. Option A introduces a variable that may not be relevant to the original question, potentially complicating the results. Option C does not address the variability inherent in a single trial, which could skew results. Option D restricts the experiment to a specific range of acidity, limiting the exploration of acid strength effects across a broader spectrum.
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.
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.
Maria places a rock in a graduated cylinder containing some water as a step in calculating the density of the rock, as shown below. What is the combined volume of the water and rock in the graduated cylinder?
- A. 9 mL
- B. 26 mL
- C. 30 mL
- D. 15 mL
Correct Answer & Rationale
Correct Answer: C
To determine the combined volume of the water and rock in the graduated cylinder, we need to consider the displacement method. When Maria adds the rock to the water, the water level rises according to the volume of the rock. If the initial water level was, for example, 20 mL, and the rock displaces an additional 10 mL, the total volume would be 30 mL. Option A (9 mL) is too low, as it does not account for the volume of both the water and the rock. Option B (26 mL) may suggest a smaller rock or lower initial water level, but does not reflect typical measurements. Option D (15 mL) is also too low, failing to include the rock's volume adequately. Thus, 30 mL accurately represents the total volume when both water and rock are combined.
To determine the combined volume of the water and rock in the graduated cylinder, we need to consider the displacement method. When Maria adds the rock to the water, the water level rises according to the volume of the rock. If the initial water level was, for example, 20 mL, and the rock displaces an additional 10 mL, the total volume would be 30 mL. Option A (9 mL) is too low, as it does not account for the volume of both the water and the rock. Option B (26 mL) may suggest a smaller rock or lower initial water level, but does not reflect typical measurements. Option D (15 mL) is also too low, failing to include the rock's volume adequately. Thus, 30 mL accurately represents the total volume when both water and rock are combined.
Which statement is a valid conclusion from the data?
- A. The male athletes used more energy than the female athletes after 30 minutes of exercise.
- B. Strenuous exercise is more difficult for male athletes than female athletes.
- C. The average increase in heart rate was lower for the females than for the males.
- D. All the females had a lower heart rate than the males after 30 minutes of exercise.
Correct Answer & Rationale
Correct Answer: C
Option C accurately reflects the data, indicating a measurable difference in heart rate between male and female athletes after 30 minutes of exercise. This conclusion is supported by the data trends, which typically show a higher average heart rate in males. Option A makes an assumption about energy expenditure without specific data to support it, making it invalid. Option B incorrectly suggests a subjective comparison of difficulty, which cannot be deduced from heart rate data alone. Lastly, Option D overgeneralizes by claiming that all females had lower heart rates than males, which is unlikely and not supported by typical statistical findings, as individual variations exist.
Option C accurately reflects the data, indicating a measurable difference in heart rate between male and female athletes after 30 minutes of exercise. This conclusion is supported by the data trends, which typically show a higher average heart rate in males. Option A makes an assumption about energy expenditure without specific data to support it, making it invalid. Option B incorrectly suggests a subjective comparison of difficulty, which cannot be deduced from heart rate data alone. Lastly, Option D overgeneralizes by claiming that all females had lower heart rates than males, which is unlikely and not supported by typical statistical findings, as individual variations exist.