Answer:20
Explanation: i konw this stuff
All electromagnetic waves travel at the same speed in a vacuum: 3.0 x 10^5 (300,000) kilometres per second. some electromagnetic waves are part of the visible light spectrum and some do emit harmful radiation, but certainly not all. they travel fine on earth without the vacuum of space too.
1.) the objects have the same temperature
this is the answer because thermal equilibrium is when two substances touch and the temperature becomes the same.
Lithium metals reacts slowly with water to form a colourless solution of lithiums hydroxide (LiOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic, but the reaction is slower than that of sodium (immediately below lithium in the periodic table)
