Amir took his little sister Erika downtown to buy her a helium balloon for her birthday. As they walked back home in the snow, the balloon shrank. Erika was disappointed. But Amir had just learned about the ideal gas law in chemistry class, and he told Erika that the balloon would be fine. Sure enough, by the time Amir and Erika got home and were taking off their coats, the balloon looked fuller.
Over the next few days, the balloon began to get smaller and smaller. Amir told Erika that if she brought the balloon on an airplane ride, it would actually get larger again.
Use this story to answer the following questions.
a. What are two major assumptions about an ideal gas?
b. Use the ideal gas law to explain the changes that the balloon underwent.
c. Fill in the table to identify the variable that was changed and the primary effect it had. Indicate if each change showed was related to an increase or a decrease.
d. The temperature inside the store was 25°C, and the balloon contained 14 L of helium. If the balloon shrank to a volume of 13 L when taken outside, what was the outdoor temperature (in Celsius)? Use Charles's law. Show your work. (2 points)
