Write the numbers in scientific notation

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

Which substance has non polar covalent bonds

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?