1 – Correct
A substance can lose heat energy without its temperature decreasing by changing state.
2 – Correct
Heat energy from the sun reaches Earth via vacuum.
3 – Correct
Intermolecular bonds between molecules of water are still unbroken at 100ºC whilst they are broken in steam at the same temperature. This causes steam to have more heat energy than water at 100ºC.
4 – Correct
Cooling or heating of water will always setup a convection current.
Hence, all statements are correct.