What are the 4 variables that describe a gas

Which best describes why nh4+ can form an ionic bond with cl-?

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.

I’m an electrically neutral atomic any element, there are equal numbers of