Correlate the biggest jump in ionization energy to the number of valence electrons in each atom

Molten iron fills a mould, which has a volume of 200 cm cubed. calculate the volume when the iron cools and solidifies.

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?

The vapour pressure of benzene is 53.3 kpa at 60.6 °c, but it fell to 51.5 kpa when 19.0 g of a non-volatile organic compound was dissolved in 500 g of benzene. calculate the molar mass of the compound.