Fe is the element Iron, the 2+ is how many electrons is lost to make the ion, so 2 electrons are lost from the valence shell (to make a full outermost shell)
Hydrogen (H) was first, followed by helium (He).
<span>NH4+ and NO3- because barium phosphate is insoluble </span>
<span> Vertical height of longest escalator in free world = 58.8 sin 32.4 = 31. 5 m
Karen's mass = 54.6 kg
Work done on Karen = mgh = 54.6(9.81)(31.5) = 1.69e4 J = 16.9 KJ ANS </span>
I'm not sure, however if you put sugar in water then the sugar particles speed up due to the fact that they dissolve in the water. Hope this helped! : D