Question
Solid carbon dioxide is commonly known as dry ice. Carbon dioxide freezes at a temperature of -78.5°C, which makes dry ice very good at keeping things cold. Liquid carbon dioxide does not exist at atmospheric pressure. Because of this, dry ice immediately changes to a gaseous state when it is warmed. This can be seen as a benefit of using dry ice, since no liquid is left in the container that is being used to keep things cold. A shipping company wants to determine how effectively dry ice can keep food frozen in a cooler system over time. A scientist at the company places a block of dry ice in a cooler and closes the lid. The picture shows the dry ice being put into the cooler.
The scientist uses an infrared thermometer to measure the temperature of the air inside the cooler over a period of 48 hours. The data collected is shown in the graph.
The graph shows 'Temperature in degrees Celsius' along the vertical axis in increments of 20 degrees, from minus 100 to 20 degrees. Along the horizontal axis is 'Time in hours,' in increments of 6 hours, from 0 to 48 hours. A line indicating 'temperature inside the cooler' starts at 20 degrees and drops rapidly to a point between minus 60 degrees and minus 80 degrees, before 6 hours. The line then drops slowly to nearly minus 80 degrees by 12 hours. After that, the line shows a slow and steady increase in temperature— it crosses minus 60 degrees by 36 hours and reaches a point between minus 20 and minus 40 degrees, by 48 hours.
Multiple Select Question
Which statements correctly describe how the energy of the carbon dioxide molecules in the dry ice changes during the first 12 hours of the experiment? Choose the two correct answers.
A.
As the average number of molecules in the cooler decreased, the thermal energy also decreased.
B.
The average kinetic energy of the carbon dioxide molecules increases as it becomes a gas.
C.
The average thermal energy of the air in the cooler increases throughout the experiment.
D.
The average thermal energy of carbon dioxide decreases throughout the experiment.
E.
As dry ice changes from a solid to a gas, it absorbs thermal energy from the surrounding air.
Answers
GPT-4o mini
The correct statements that describe how the energy of the carbon dioxide molecules in the dry ice changes during the first 12 hours of the experiment are:
**B.** The average kinetic energy of the carbon dioxide molecules increases as it becomes a gas.
**D.** The average thermal energy of carbon dioxide decreases throughout the experiment.
**Explanation:**
- **B** is correct because, as dry ice (solid carbon dioxide) sublimates to gas, the kinetic energy of the molecules increases, since gaseous molecules move more freely and have higher energy compared to solid molecules.
- **D** is correct because throughout the first 12 hours, the temperature inside the cooler drops significantly, indicating that the average thermal energy of the carbon dioxide decreases as it changes from solid to gas and absorbs heat from the surrounding air.
**A** is not correct because the problem does not mention a decrease in the number of molecules; dry ice sublimates to add gas molecules to the air inside the cooler.
**C** is incorrect because the thermal energy of the air in the cooler does not increase; rather, it decreases as the dry ice cools the air.
**E** is not correct as it suggests that dry ice absorbs thermal energy from the surroundings while sublimating; instead, it loses thermal energy to the surrounding air as it changes phase.
**B.** The average kinetic energy of the carbon dioxide molecules increases as it becomes a gas.
**D.** The average thermal energy of carbon dioxide decreases throughout the experiment.
**Explanation:**
- **B** is correct because, as dry ice (solid carbon dioxide) sublimates to gas, the kinetic energy of the molecules increases, since gaseous molecules move more freely and have higher energy compared to solid molecules.
- **D** is correct because throughout the first 12 hours, the temperature inside the cooler drops significantly, indicating that the average thermal energy of the carbon dioxide decreases as it changes from solid to gas and absorbs heat from the surrounding air.
**A** is not correct because the problem does not mention a decrease in the number of molecules; dry ice sublimates to add gas molecules to the air inside the cooler.
**C** is incorrect because the thermal energy of the air in the cooler does not increase; rather, it decreases as the dry ice cools the air.
**E** is not correct as it suggests that dry ice absorbs thermal energy from the surroundings while sublimating; instead, it loses thermal energy to the surrounding air as it changes phase.