Answer:
If anything but H2O were found, it would be evidence of a chemical change. Therefore, 4 is the only viable evidence that it was a physical change of H2O liquid to H2O gas.
The answer is lower. when there’s a lower temperature the molecules will be moving at a lower speed. a lower speed means less thermal energy.
Answer:
Mechanical energy
Explanation:
because the heat energy turn into a mechanical energy that spins the engine
Answer: A) True
Explanation: The difference in energy levels in an atom is responsible for the emission of photons. Emitted photons have different energies because energy levels are discrete. The energy of a photon gives information about its frequency and subsequently, its colour.
As the two gases (Hydrogen & Helium) are distinctively different gases with different discrete energy levels in their atoms, it is logical that the frequency and colour of the emitted photons from their respective atoms would be different.
