A gas is at the standard pressure with a volume a 1.25L. If the volume decreases to 1.00 L what is the new pressure?

Can someone me with questions 15 to 17 plz.

Freezing and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules