What are 6 uses of filtration?

Which of the following nuclei would be the least stable a 2 protons, 2 neutrons b 1 proton 1 neutron c 1 proton 3 neutrons d 1 proton 2 neutrons

The size (radius) of an oxygen molecule is about 2.0 ×10−10m. make a rough estimate of the pressure at which the finite volume of the molecules should cause noticeable deviations from ideal-gas behavior at ordinary temperatures (t= 300k ). assume that deviatons would be noticeable when volume of the gas per molecule equals the volume of the molecule itself.

In the diagram here that represents the reaction, which reactant, a or b, is the limiting reagent?