How much energy is needed to change 25 grams of ice at -7ºC to water at 45ºC ?

Compare and contrast physical changes with chemical changes.

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 ?

All forces cause motion? true or false