White powder, when heated, produces a colourless gas and a black solid. is the white powder and element?

(apex) when a cup of water is dropped, as the cup falls, the water in the cup falls out true or false?

Agas diffuses 1/7 times faster than hydrogen gas (h2). what is the molar mass of the gas? 100.10 g/mol 98.78 g/mol 86.68 g/mol 79.98 g/mol

What was bohr’s contribution to the planetary model