What other substance could be in the water besides rust?

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

How is the shape of the poem “peer” connected to its meaning?