Does anyone have the answer key to half life gizmos

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.

How air particles exert a pressure on the inside of the balloon

If 1.8 l of water is added to 2.5l of a 7.0 molarity koh solution, what is the molarity of the new solution