Describe a physical change in which a substance appears to change chemically

Which object forms when a supergiant runs out of fuel? a red giant a black hole a white dwarf a neutron star

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

If i initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 k, and then i raise the pressure to 14 atm and increase the temperature to 300 k, what is the new volume of the gas?