1. For which properties can a student design an investigation of the electrostatic forces between molecules in a substance? (1 point)
A. boiling point, but not melting point, surface tension, or vapor pressure
B. melting point, boiling point, surface tension, and vapor pressure ***
C. melting point and boiling point, but not surface tension and vapor pressure
D. surface tension and vapor pressure, but not melting point and boiling point
2. A student decides to conduct an investigation to determine the boiling points of water and ethanol. The student will heat samples of water and ethanol, and measure the temperature at which the samples boil. The student will conduct the investigation three times. Which aspect is missing from the experimental design? (1 point)
A. determining what data to collect
B. deciding on the number of trials to perform
C. determining the procedure
D. deciding on the appropriate equipment ***
3. To determine the melting point of ice, which procedure would best help measure the melting point temperature? (1 point)
A. Mix ice with water until equilibrium is reached but some ice remains that is still melting. ***
B. Mix ice with water until equilibrium is reached but some ice remains that is no longer melting.
C. Mix ice with water until just before equilibrium is reached but some ice remains that is still melting.
D. Mix ice with water until just before equilibrium is reached but some ice remains that is no longer melting.
4. Why is it important to conduct multiple trials of an investigation to determine the melting point of ice? (1 point)
A. It helps decrease human error.
B. It ensures that results are accurate. ***
C. It reduces the materials needed for the investigation.
D. It lets scientists manipulate data to meet their needs.
5. A student performs four trials of an investigation to determine the boiling point of water. How should the student handle the results? (1 point)
A. The student should take the average of the results from all four trials. ***
B. The student should take the average of the minimum and maximum value of the results.
C. The student should use the maximum value of the results.
D. The student should use the value that is closest to 100ºC.
I'd really appreciate some conformation on my answers. Thank you in advance!
1. B. melting point, boiling point, surface tension, and vapor pressure
2. D. deciding on the appropriate equipment
3. A. Mix ice with water until equilibrium is reached but some ice remains that is still melting.
4. B. It ensures that results are accurate.
5. A. The student should take the average of the results from all four trials.
These answers are correct. Congratulations! Keep up the good work!
1. Correct answer: B. melting point, boiling point, surface tension, and vapor pressure.
To determine the properties for which a student can design an investigation of the electrostatic forces between molecules in a substance, you can analyze each option.
- Option A states that you can only design an investigation for the boiling point, but not for melting point, surface tension, or vapor pressure. This is incorrect because the topic is about investigating electrostatic forces between molecules, not just boiling point.
- Option B correctly states that a student can design an investigation for the melting point, boiling point, surface tension, and vapor pressure. These properties are all related to the intermolecular forces in a substance.
- Option C states that you can only design an investigation for the melting point and boiling point, but not for surface tension and vapor pressure. This is incorrect because surface tension and vapor pressure are also related to the intermolecular forces.
- Option D states that you can design an investigation for surface tension and vapor pressure, but not for melting point and boiling point. This is incorrect because these properties are also related to the intermolecular forces.
Therefore, the correct answer is B. melting point, boiling point, surface tension, and vapor pressure.
2. Correct answer: D. deciding on the appropriate equipment.
To identify the missing aspect from the experimental design of determining the boiling points of water and ethanol, analyze each option:
- Option A states "determining what data to collect." This is not missing because the temperature at which the samples boil is already specified.
- Option B states "deciding on the number of trials to perform." This is not missing either because the student is conducting the investigation three times, as mentioned in the question.
- Option C states "determining the procedure." This is not missing because the procedure is clearly stated as heating the samples and measuring the temperature at which they boil.
- Option D states "deciding on the appropriate equipment." This is the missing aspect. The question does not mention what equipment the student will use to heat the samples and measure the boiling temperatures. Therefore, the correct answer is D. deciding on the appropriate equipment.
3. Correct answer: A. Mix ice with water until equilibrium is reached but some ice remains that is still melting.
To determine the melting point of ice, analyzing each option:
- Option A states that you should mix ice with water until equilibrium is reached, but some ice remains that is still melting. This is the best procedure because when the ice is still melting, it means it has not reached its melting point yet. By keeping some ice in the mixture, you ensure that the temperature is still at the melting point.
- Option B states that you should mix ice with water until equilibrium is reached, but some ice remains that is no longer melting. This procedure is incorrect because if the ice is no longer melting, it means the temperature has already risen above its melting point.
- Option C states that you should mix ice with water until just before equilibrium is reached, but some ice remains that is still melting. This is incorrect because if the ice is still melting, it means the temperature is still at the melting point.
- Option D states that you should mix ice with water until just before equilibrium is reached, but some ice remains that is no longer melting. This procedure is incorrect because if the ice is no longer melting, it means the temperature has already risen above its melting point.
Therefore, the correct answer is A. Mix ice with water until equilibrium is reached, but some ice remains that is still melting.
4. Correct answer: B. It ensures that results are accurate.
To determine why it is important to conduct multiple trials of an investigation to determine the melting point of ice, analyze each option:
- Option A states that conducting multiple trials helps decrease human error. While multiple trials can help identify and reduce systematic errors, they do not directly decrease human error. This is incorrect.
- Option B states that conducting multiple trials ensures that the results are accurate. This is the correct answer because multiple trials can help identify outliers, inconsistencies, or errors that can affect the accuracy of the results. By averaging multiple trials, you can obtain a more reliable and representative value for the melting point of ice.
- Option C states that conducting multiple trials reduces the materials needed for the investigation. While this may be true, it is not the main reason for conducting multiple trials. This is incorrect.
- Option D states that conducting multiple trials lets scientists manipulate data to meet their needs. This is incorrect because conducting multiple trials is not about manipulating data but obtaining accurate and reliable results.
Therefore, the correct answer is B. It ensures that results are accurate.
5. Correct answer: A. The student should take the average of the results from all four trials.
To determine how the student should handle the results of four trials to determine the boiling point of water, analyze each option:
- Option A states that the student should take the average of the results from all four trials. This is the correct answer because by taking the average, you can reduce the impact of any outliers or random variations in the results and obtain a more representative value for the boiling point of water.
- Option B states that the student should take the average of the minimum and maximum value of the results. This approach may not accurately represent the boiling point because outliers at either extreme end might disproportionately influence the average. This is incorrect.
- Option C states that the student should use the maximum value of the results. This approach may give a higher value but does not consider other data points. This is incorrect.
- Option D states that the student should use the value that is closest to 100ºC. While the boiling point of water is around 100ºC, not all trials may result in exactly 100ºC. This approach does not consider variations in experimental results and is not statistically representative. This is incorrect.
Therefore, the correct answer is A. The student should take the average of the results from all four trials.
1. B. melting point, boiling point, surface tension, and vapor pressure
2. D. deciding on the appropriate equipment
3. A. Mix ice with water until equilibrium is reached but some ice remains that is still melting.
4. B. It ensures that results are accurate.
5. A. The student should take the average of the results from all four trials.
Your answers are correct! Well done!