When potassium is added to water the metal melts and floats. It moves around very quickly in the surface of the water.
1 mole H2O ---------------------- 6.02x10²³ molecules
4 moles H2O--------------------- y molecules
y = 4 * 6.02x10²³
y = 2.4x10^24 molecules
answer b
hope this helps!.
